Shift+Ctrl+Z now works for redo

Closes #9

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = tab
+indent_size = 8
+charset = utf-8
+
+[*.md]
+indent_style = space
+indent_size = 2

README.md

@@ -2,5 +2,26 @@
 
 [![Go Reference](https://pkg.go.dev/badge/git.tebibyte.media/tomo/objects.svg)](https://pkg.go.dev/git.tebibyte.media/tomo/objects)
 
-Objects contains a standard collection of re-usable objects. All objects in this
-module visually conform to whatever the theme is set to.
+Objects contains a standard collection of re-usable objects. It should be viewed
+also as a reference for how to create custom objects in Tomo.
+
+## Styling
+All objects in this module have roles of the form:
+
+```
+objects.TypeName
+```
+
+Where `TypeName` is the exact Go type name of the object in question. Objects
+may also have different tags to indicate variations, states, etc. If applicable,
+they are listed and described in the doc comment for the object's type. More
+complex objects may have sub-components that are not accessible from the API.
+These are listed alongside the tags.
+
+## Setting Attributes
+It is generally not recommended to set attributes on these objects. However, if
+you must, they can be set by obtaining the object's underlying box through the
+`GetBox` method. Be aware that the exact type of box that is returned here is
+not part of the API, and may change unexpectedly even after v1.0. This caveat
+also applies to boxes/sub-components making up the internal composition of the
+objects.

button.go

@@ -5,13 +5,18 @@ import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/objects/layouts"
 
-var buttonLayout     = layouts.NewGrid([]bool { true        }, []bool { true })
-var iconButtonLayout = layouts.NewGrid([]bool { true        }, []bool { true })
-var bothButtonLayout = layouts.NewGrid([]bool { false, true }, []bool { true })
+var _ tomo.Object = new(Button)
+
+var buttonLayout     = layouts.Row { true        }
+var iconButtonLayout = layouts.Row { true        }
+var bothButtonLayout = layouts.Row { false, true }
 
 // Button is a clickable button.
+//
+// Tags:
+//   - [icon] The button has an icon.
 type Button struct {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 
 	label *Label
 	icon  *Icon
@@ -24,36 +29,45 @@ type Button struct {
 
 // NewButton creates a new button with the specified text.
 func NewButton (text string) *Button {
-	box := &Button {
-		ContainerBox: tomo.NewContainerBox(),
-		label:        NewLabel(text),
+	button := &Button {
+		box:   tomo.NewContainerBox(),
+		label: NewLabel(text),
 	}
-	box.SetRole(tomo.R("objects", "Button", ""))
-	tomo.Apply(box)
-	box.label.SetAlign(tomo.AlignMiddle, tomo.AlignMiddle)
-	box.SetLayout(buttonLayout)
-	box.SetText(text)
+	button.box.SetRole(tomo.R("objects", "Button"))
+	button.label.SetAlign(tomo.AlignMiddle, tomo.AlignMiddle)
+	button.box.SetAttr(tomo.ALayout(buttonLayout))
+	button.SetText(text)
 	
-	box.CaptureDND(true)
-	box.CaptureMouse(true)
-	box.CaptureScroll(true)
-	box.CaptureKeyboard(true)
-	
-	box.OnMouseUp(box.handleMouseUp)
-	box.OnKeyUp(box.handleKeyUp)
-	box.SetFocusable(true)
-	return box
+	button.box.SetInputMask(true)
+	button.box.OnButtonDown(button.handleButtonDown)
+	button.box.OnButtonUp(button.handleButtonUp)
+	button.box.OnKeyDown(button.handleKeyDown)
+	button.box.OnKeyUp(button.handleKeyUp)
+	button.box.SetFocusable(true)
+	return button
+}
+
+// GetBox returns the underlying box.
+func (this *Button) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this button has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *Button) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
 }
 
 // SetText sets the text of the button's label.
 func (this *Button) SetText (text string) {
 	this.label.SetText(text)
 	if this.labelActive && text == "" {
-		this.Remove(this.label)
+		this.box.Remove(this.label)
 		this.labelActive = false
 	}
 	if !this.labelActive && text != "" {
-		this.Add(this.label)
+		this.box.Add(this.label)
 		this.labelActive = true
 	}
 	this.applyLayout()
@@ -62,7 +76,7 @@ func (this *Button) SetText (text string) {
 // SetIcon sets an icon for this button. Setting the icon to IconUnknown will
 // remove it.
 func (this *Button) SetIcon (id tomo.Icon) {
-	if this.icon != nil { this.Remove(this.icon) }
+	if this.icon != nil { this.box.Remove(this.icon) }
 
 	var icon *Icon; if id != tomo.IconUnknown {
 		icon = NewIcon(id, tomo.IconSizeSmall)
@@ -70,8 +84,9 @@ func (this *Button) SetIcon (id tomo.Icon) {
 	this.icon = icon
 
 	if this.icon != nil {
-		this.Insert(this.icon, this.label)
+		this.box.Insert(this.icon, this.label)
 	}
+	this.box.SetTag("icon", this.icon != nil)
 	this.applyLayout()
 }
 
@@ -82,22 +97,34 @@ func (this *Button) OnClick (callback func ()) event.Cookie {
 
 func (this *Button) applyLayout () {
 	if this.labelActive && this.icon == nil {
-		this.SetLayout(buttonLayout)
+		this.box.SetAttr(tomo.ALayout(buttonLayout))
 	} else if !this.labelActive && this.icon != nil {
-		this.SetLayout(iconButtonLayout)
+		this.box.SetAttr(tomo.ALayout(iconButtonLayout))
 	} else {
-		this.SetLayout(bothButtonLayout)
+		this.box.SetAttr(tomo.ALayout(bothButtonLayout))
 	}
 }
 
-func (this *Button) handleKeyUp (key input.Key, numberPad bool) {
-	if key != input.KeyEnter && key != input.Key(' ') { return }
+func (this *Button) handleKeyDown (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
 	this.on.click.Broadcast()
+	return true
 }
 
-func (this *Button) handleMouseUp (button input.Button) {
-	if button != input.ButtonLeft { return }
-	if this.MousePosition().In(this.Bounds()) {
+func (this *Button) handleKeyUp (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
+	return true
+}
+
+func (this *Button) handleButtonDown (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	return true
+}
+
+func (this *Button) handleButtonUp (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.on.click.Broadcast()
 	}
+	return true
 }

calendar.go

@@ -0,0 +1,190 @@
+package objects
+
+import "fmt"
+import "time"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+var _ tomo.Object = new(Calendar)
+
+// Calendar is an object that can display a date and allow the user to change
+// it. It can display one month at a time.
+// 
+// Sub-components:
+//   - CalendarGrid organizes the days into a grid.
+//   - CalendarWeekdayHeader appears at the top of each grid column, and shows
+//     the day of the week that column represents.
+//   - CalendarDay appears within the grid for each day of the current month.
+//
+// CalendarDay tags:
+//   - [weekend] The day is a weekend.
+//   - [weekday] The day is a weekday.
+type Calendar struct {
+	box tomo.ContainerBox
+	
+	grid tomo.ContainerBox
+	time time.Time
+	monthLabel *Label
+	
+	on struct {
+		valueChange event.FuncBroadcaster
+	}
+}
+
+// NewCalendar creates a new calendar with the specified date.
+func NewCalendar (tm time.Time) *Calendar {
+	calendar := &Calendar {
+		box:  tomo.NewContainerBox(),
+		time: tm,
+	}
+	calendar.box.SetRole(tomo.R("objects", "Calendar"))
+	calendar.box.SetAttr(tomo.ALayout(layouts.ContractVertical))
+	
+	prevButton := NewButton("")
+	prevButton.SetIcon(tomo.IconGoPrevious)
+	prevButton.OnClick(func () {
+		calendar.prevMonth()
+		calendar.on.valueChange.Broadcast()
+	})
+	nextButton := NewButton("")
+	nextButton.SetIcon(tomo.IconGoNext)
+	nextButton.OnClick(func () {
+		calendar.nextMonth()
+		calendar.on.valueChange.Broadcast()
+	})
+	calendar.monthLabel = NewLabel("")
+	calendar.monthLabel.SetAlign(tomo.AlignMiddle, tomo.AlignMiddle)
+	
+	calendar.grid = tomo.NewContainerBox()
+	calendar.grid.SetRole(tomo.R("objects", "CalendarGrid"))
+	calendar.grid.SetAttr(tomo.ALayout(layouts.NewGrid (
+		true, true, true, true, true, true, true)()))
+	calendar.box.Add(NewInnerContainer (
+		layouts.Row { false, true, false },
+		prevButton, calendar.monthLabel, nextButton))
+	calendar.box.Add(calendar.grid)
+	
+	calendar.box.OnScroll(calendar.handleScroll)
+	
+	calendar.refresh()
+	return calendar
+}
+
+// GetBox returns the underlying box.
+func (this *Calendar) GetBox () tomo.Box {
+	return this.box
+}
+
+// Value returns the time this calendar is displaying.
+func (this *Calendar) Value () time.Time {
+	return this.time
+}
+
+// SetValue sets the date the calendar will display.
+func (this *Calendar) SetValue (tm time.Time) {
+	if this.time == tm { return }
+	this.time = tm
+	this.refresh()
+}
+
+// OnValueChange sets a function to be called when the user changes the date on
+// the calendar.
+func (this *Calendar) OnValueChange (callback func ()) {
+	this.on.valueChange.Connect(callback)
+}
+
+func (this *Calendar) prevMonth () {
+	this.time = firstOfMonth(this.time.Add(24 * time.Hour * -20))
+	this.refresh()
+}
+
+func (this *Calendar) nextMonth () {
+	this.time = firstOfMonth(this.time.Add(24 * time.Hour * 40))
+	this.refresh()
+}
+
+var weekdayAbbreviations = []string {
+	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
+}
+
+func (this *Calendar) refresh () {
+	this.monthLabel.SetText(this.time.Format("2006 January"))
+
+	this.grid.Clear()
+	for _, day := range weekdayAbbreviations {
+		dayLabel := tomo.NewTextBox()
+		dayLabel.SetRole(tomo.R("objects", "CalendarWeekdayHeader"))
+		dayLabel.SetText(day)
+		dayLabel.SetAttr(tomo.AAlign(tomo.AlignMiddle, tomo.AlignMiddle))
+		this.grid.Add(dayLabel)
+	}
+	
+	dayIter := 0 - int(firstOfMonth(this.time).Weekday())
+	if dayIter <= -6 {
+		dayIter = 1
+	}
+	weekday := 0
+	totalDays := daysInMonth(this.time)
+	for ; dayIter <= totalDays; dayIter ++ {
+		weekday = (weekday + 1) % 7
+		if dayIter > 0 {
+			day := tomo.NewTextBox()
+			day.SetText(fmt.Sprint(dayIter))
+			if weekday == 1 || weekday == 0 {
+				day.SetRole(tomo.R("objects", "CalendarDay"))
+				day.SetTag("weekend", true)
+			} else {
+				day.SetRole(tomo.R("objects", "CalendarDay"))
+				day.SetTag("weekday", true)
+			}
+			this.grid.Add(day)
+		} else {
+			this.grid.Add(tomo.NewBox())
+		}
+	}
+}
+
+func (this *Calendar) handleScroll (x, y float64) bool {
+	if y < 0 {
+		this.prevMonth()
+	} else {
+		this.nextMonth()
+	}
+	return true
+}
+
+func firstOfMonth (tm time.Time) time.Time {
+	return time.Date(tm.Year(), tm.Month(), 0, 0, 0, 0, 0, time.Local)
+}
+
+func daysInMonth (tm time.Time) (days int) {
+	year  := tm.Year()
+	month := tm.Month()
+	switch month {
+	case 1:  days = 31
+	case 2:
+		// betcha didn't know this about leap years
+		if year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) {
+			days = 29
+		} else {
+			days = 28
+		}
+	case 3:  days = 31
+	case 4:  days = 30
+	case 5:  days = 31
+	case 6:  days = 30
+	case 7:  days = 31
+	case 8:  days = 31
+	case 9:  days = 30
+	case 10: days = 31
+	case 11: days = 30
+	case 12: days = 31
+	}
+
+	return
+}
+
+func canonMonth (tm time.Time) int {
+	return int(tm.Month() - 1) + tm.Year() * 12
+}

checkbox.go

@@ -4,9 +4,15 @@ import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 
+var _ tomo.Object = new(Checkbox)
+
 // Checkbox is a control that can be toggled.
+//
+// Tags:
+//   - [checked] The checkbox's value is true.
+//   - [unchecked] The checkbox's value is false.
 type Checkbox struct {
-	tomo.Box
+	box tomo.Box
 	value bool
 	on struct {
 		valueChange event.FuncBroadcaster
@@ -15,32 +21,30 @@ type Checkbox struct {
 
 // NewCheckbox creates a new checkbox with the specified value.
 func NewCheckbox (value bool) *Checkbox {
-	box := &Checkbox {
-		Box: tomo.NewBox(),
+	checkbox := &Checkbox {
+		box: tomo.NewBox(),
 	}
-	box.SetRole(tomo.R("objects", "Checkbox", ""))
-	tomo.Apply(box)
-	box.SetValue(false)
+	checkbox.box.SetRole(tomo.R("objects", "Checkbox"))
+	checkbox.SetValue(value)
 	
-	box.OnMouseUp(box.handleMouseUp)
-	box.OnKeyUp(box.handleKeyUp)
-	box.SetFocusable(true)
-	return box
+	checkbox.box.OnButtonDown(checkbox.handleButtonDown)
+	checkbox.box.OnButtonUp(checkbox.handleButtonUp)
+	checkbox.box.OnKeyDown(checkbox.handleKeyDown)
+	checkbox.box.OnKeyUp(checkbox.handleKeyUp)
+	checkbox.box.SetFocusable(true)
+	return checkbox
 }
 
-// SetValue sets the value of the checkbox.
-func (this *Checkbox) SetValue (value bool) {
-	this.value = value
-	if this.value {
-		this.SetTextureCenter(tomo.IconCheckboxChecked.Texture(tomo.IconSizeSmall))
-	} else {
-		this.SetTextureCenter(tomo.IconCheckboxUnchecked.Texture(tomo.IconSizeSmall))
-	}
+// GetBox returns the underlying box.
+func (this *Checkbox) GetBox () tomo.Box {
+	return this.box
 }
 
-// Toggle toggles the value of the checkbox between true and false.
-func (this *Checkbox) Toggle () {
-	this.SetValue(!this.Value())
+// SetFocused sets whether or not this checkbox has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *Checkbox) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
 }
 
 // Value returns the value of the checkbox.
@@ -48,20 +52,45 @@ func (this *Checkbox) Value () bool {
 	return this.value
 }
 
-// OnValueChange specifies a function to be called when the checkbox's value
-// changes.
+// SetValue sets the value of the checkbox.
+func (this *Checkbox) SetValue (value bool) {
+	this.value = value
+	// the theme shall decide what checked and unchecked states look like
+	this.box.SetTag("checked",    value)
+	this.box.SetTag("unchecked", !value)
+}
+
+// Toggle toggles the value of the checkbox between true and false.
+func (this *Checkbox) Toggle () {
+	this.SetValue(!this.Value())
+}
+
+// OnValueChange specifies a function to be called when the user checks or
+// unchecks the checkbox.
 func (this *Checkbox) OnValueChange (callback func ()) event.Cookie {
 	return this.on.valueChange.Connect(callback)
 }
 
-func (this *Checkbox) handleKeyUp (key input.Key, numberPad bool) {
-	if key != input.KeyEnter && key != input.Key(' ') { return }
+func (this *Checkbox) handleKeyDown (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
 	this.Toggle()
+	return true
 }
 
-func (this *Checkbox) handleMouseUp (button input.Button) {
-	if button != input.ButtonLeft { return }
-	if this.MousePosition().In(this.Bounds()) {
+func (this *Checkbox) handleKeyUp (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false}
+	return true
+}
+
+func (this *Checkbox) handleButtonDown (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	return true
+}
+
+func (this *Checkbox) handleButtonUp (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.Toggle()
 	}
+	return true
 }

colorpicker.go

@@ -0,0 +1,178 @@
+package objects
+
+import "image/color"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/objects/layouts"
+import icolor "git.tebibyte.media/tomo/objects/internal/color"
+
+var _ tomo.Object = new(HSVAColorPicker)
+
+// HSVAColorPicker allows the user to pick a color by controlling its HSVA
+// parameters.
+//
+// Sub-components:
+//   - ColorPickerMap is a recangular control where the X axis controls
+//     saturation and the Y axis controls value.
+type HSVAColorPicker struct {
+	box tomo.ContainerBox
+	value icolor.HSVA
+	
+	pickerMap   *hsvaColorPickerMap
+	hueSlider   *Slider
+	alphaSlider *Slider
+	
+	on struct {
+		valueChange event.FuncBroadcaster
+	}
+}
+
+// NewHSVAColorPicker creates a new color picker with the specified color.
+func NewHSVAColorPicker (value color.Color) *HSVAColorPicker {
+	picker := &HSVAColorPicker {
+		box: tomo.NewContainerBox(),
+	}
+	picker.box.SetRole(tomo.R("objects", "ColorPicker"))
+	picker.box.SetAttr(tomo.ALayout(layouts.Row { true, false, false }))
+	picker.pickerMap = newHsvaColorPickerMap(picker)
+	picker.box.Add(picker.pickerMap)
+	
+	picker.hueSlider = NewVerticalSlider(0.0)
+	picker.box.Add(picker.hueSlider)
+	picker.hueSlider.OnValueChange(func () {
+		picker.value.H = picker.hueSlider.Value()
+		picker.on.valueChange.Broadcast()
+		picker.pickerMap.Invalidate()
+	})
+	
+	picker.alphaSlider = NewVerticalSlider(0.0)
+	picker.box.Add(picker.alphaSlider)
+	picker.alphaSlider.OnValueChange(func () {
+		picker.value.A = uint16(picker.alphaSlider.Value() * 0xFFFF)
+		picker.on.valueChange.Broadcast()
+		picker.pickerMap.Invalidate()
+	})
+	
+	if value == nil { value = color.Transparent }
+	picker.SetValue(value)
+	return picker
+}
+
+// GetBox returns the underlying box.
+func (this *HSVAColorPicker) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this color picker has keyboard focus. If set
+// to true, this method will steal focus away from whichever object currently
+// has focus.
+func (this *HSVAColorPicker) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// Value returns the color of the picker.
+func (this *HSVAColorPicker) Value () color.Color {
+	return this.value
+}
+
+// SetValue sets the color of the picker.
+func (this *HSVAColorPicker) SetValue (value color.Color) {
+	if value == nil { value = color.Transparent }
+	this.value = icolor.HSVAModel.Convert(value).(icolor.HSVA)
+	this.hueSlider.SetValue(this.value.H)
+	this.alphaSlider.SetValue(float64(this.value.A) / 0xFFFF)
+	this.pickerMap.Invalidate()
+}
+
+// OnValueChange specifies a function to be called when the user changes the
+// swatch's color.
+func (this *HSVAColorPicker) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
+}
+
+// RGBA satisfies the color.Color interface
+func (this *HSVAColorPicker) RGBA () (r, g, b, a uint32) {
+	return this.value.RGBA()
+}
+
+type hsvaColorPickerMap struct {
+	tomo.CanvasBox
+	dragging bool
+	parent *HSVAColorPicker
+}
+
+func newHsvaColorPickerMap (parent *HSVAColorPicker) *hsvaColorPickerMap {
+	picker := &hsvaColorPickerMap {
+		CanvasBox: tomo.NewCanvasBox(),
+		parent: parent,
+	}
+	picker.SetDrawer(picker)
+	picker.SetRole(tomo.R("objects", "ColorPickerMap"))
+	picker.OnButtonUp(picker.handleButtonUp)
+	picker.OnButtonDown(picker.handleButtonDown)
+	picker.OnMouseMove(picker.handleMouseMove)
+	return picker
+}
+
+func (this *hsvaColorPickerMap) handleButtonDown (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	this.dragging = true
+	this.drag()
+	return true
+}
+
+func (this *hsvaColorPickerMap) handleButtonUp (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	this.dragging = false
+	return true
+}
+
+func (this *hsvaColorPickerMap) handleMouseMove () bool {
+	if !this.dragging { return false }
+	this.drag()
+	return true
+}
+
+func (this *hsvaColorPickerMap) drag () {
+	pointer := this.Window().MousePosition()
+	bounds  := this.InnerBounds()
+	this.parent.value.S =     float64(pointer.X - bounds.Min.X) / float64(bounds.Dx())
+	this.parent.value.V = 1 - float64(pointer.Y - bounds.Min.Y) / float64(bounds.Dy())
+	this.parent.value = this.parent.value.Canon()
+	this.parent.on.valueChange.Broadcast()
+	this.Invalidate()
+}
+
+func (this *hsvaColorPickerMap) Draw (can canvas.Canvas) {
+	bounds := can.Bounds()
+	for y := bounds.Min.Y; y < bounds.Max.Y; y ++ {
+	for x := bounds.Min.X; x < bounds.Max.X; x ++ {
+		xx := x - bounds.Min.X
+		yy := y - bounds.Min.Y
+		
+		pixel := icolor.HSVA {
+			H: this.parent.value.H,
+			S:     float64(xx) / float64(bounds.Dx()),
+			V: 1 - float64(yy) / float64(bounds.Dy()),
+			A: 0xFFFF,
+		}
+		
+		sPos := int(     this.parent.value.S  * float64(bounds.Dx()))
+		vPos := int((1 - this.parent.value.V) * float64(bounds.Dy()))
+		sDist := sPos - xx
+		vDist := vPos - yy
+		crosshair :=
+			(sDist == 0 || vDist == 0) &&
+			-8 < sDist && sDist < 8 &&
+			-8 < vDist && vDist < 8
+		if crosshair {
+			pixel.S = 1 - pixel.S
+			pixel.V = 1 - pixel.V
+		}
+		
+		can.Set(x, y, pixel)
+	}}
+}
+

container.go

@@ -1,21 +1,32 @@
 package objects
 
+import "image"
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+
+var _ tomo.ContentObject = new(Container)
 
 // Container is an object that can contain other objects. It can be used as a
-// primitive for building more complex layouts. It has two variants: an outer
-// container, and an inner container. The outer container has padding around
-// its edges, whereas the inner container does not. The container will have a
-// corresponding object role variation of either "outer" or "inner".
+// primitive for building more complex layouts. It has two main variants: an
+// outer container, and an inner container. The outer container has padding
+// around its edges, whereas the inner container does not. It also has a
+// "sunken" variation designed to hold a scrolled list of items.
+//
+// Tags:
+//   - [outer] The container is the root of a window.
+//   - [inner] The container is within another container, and is part of a
+//     larger layout.
+//   - [sunken] The container holds a visually grouped, usually scrolled, list
+//     of items.
 type Container struct {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 }
 
 func newContainer (layout tomo.Layout, children ...tomo.Object) *Container {
 	this := &Container {
-		ContainerBox: tomo.NewContainerBox(),
+		box: tomo.NewContainerBox(),
 	}
-	this.SetLayout(layout)
+	this.box.SetAttr(tomo.ALayout(layout))
 	for _, child := range children {
 		this.Add(child)
 	}
@@ -27,8 +38,8 @@ func newContainer (layout tomo.Layout, children ...tomo.Object) *Container {
 // window, tab pane, etc.
 func NewOuterContainer (layout tomo.Layout, children ...tomo.Object) *Container {
 	this := newContainer(layout, children...)
-	this.SetRole(tomo.R("objects", "Container", "outer"))
-	tomo.Apply(this)
+	this.box.SetRole(tomo.R("objects", "Container"))
+	this.box.SetTag("outer", true)
 	return this
 }
 
@@ -36,16 +47,87 @@ func NewOuterContainer (layout tomo.Layout, children ...tomo.Object) *Container
 // around it. It is meant to be used as a root container for a ScrollContainer.
 func NewSunkenContainer (layout tomo.Layout, children ...tomo.Object) *Container {
 	this := newContainer(layout, children...)
-	this.SetRole(tomo.R("objects", "Container", "sunken"))
-	tomo.Apply(this)
+	this.box.SetRole(tomo.R("objects", "Container"))
+	this.box.SetTag("sunken", true)
 	return this
 }
 
 // NewInnerContainer creates a new container that has no padding around it.
 func NewInnerContainer (layout tomo.Layout, children ...tomo.Object) *Container {
 	this := newContainer(layout, children...)
-	this.SetRole(tomo.R("objects", "Container", "inner"))
-	tomo.Apply(this)
+	this.box.SetRole(tomo.R("objects", "Container"))
+	this.box.SetTag("inner", true)
 	return this
 }
 
+// GetBox returns the underlying box.
+func (this *Container) GetBox () tomo.Box {
+	return this.box
+}
+
+// ContentBounds returns the bounds of the inner content of the container
+// relative to the container's InnerBounds.
+func (this *Container) ContentBounds () image.Rectangle {
+	return this.box.ContentBounds()
+}
+
+// ScrollTo shifts the origin of the container's content to the origin of the
+// container's InnerBounds, offset by the given point.
+func (this *Container) ScrollTo (position image.Point) {
+	this.box.ScrollTo(position)
+}
+
+// OnContentBoundsChange specifies a function to be called when the container's
+// ContentBounds or InnerBounds changes.
+func (this *Container) OnContentBoundsChange (callback func ()) event.Cookie {
+	return this.box.OnContentBoundsChange(callback)
+}
+
+// SetLayout sets the layout of the container.
+func (this *Container) SetLayout (layout tomo.Layout) {
+	this.box.SetAttr(tomo.ALayout(layout))
+}
+
+// SetAlign sets the X and Y alignment of the container.
+func (this *Container) SetAlign (x, y tomo.Align) {
+	this.box.SetAttr(tomo.AAlign(x, y))
+}
+
+// SetOverflow sets the X and Y overflow of the container.
+func (this *Container) SetOverflow (x, y bool) {
+	this.box.SetAttr(tomo.AOverflow(x, y))
+}
+
+// Add appends a child object. If the object is already a child of another
+// object, it will be removed from that object first.
+func (this *Container) Add (object tomo.Object) {
+	this.box.Add(object)
+}
+
+// Remove removes a child object, if it is a child of this container.
+func (this *Container) Remove (object tomo.Object) {
+	this.box.Remove(object)
+}
+
+// Insert inserts a child object before a specified object. If the before object
+// is nil or is not contained within this container, the inserted object is
+// appended. If the inserted object is already a child of another object, it
+// will be removed from that object first.
+func (this *Container) Insert (child tomo.Object, before tomo.Object) {
+	this.box.Insert(child, before)
+}
+
+// Clear removes all child objects.
+func (this *Container) Clear () {
+	this.box.Clear()
+}
+
+// Len returns hte amount of child objects.
+func (this *Container) Len () int {
+	return this.box.Len()
+}
+
+// At returns the child object at the specified index.
+func (this *Container) At (index int) tomo.Object {
+	return this.box.At(index)
+}

dialog.go

@@ -16,7 +16,7 @@ type DialogKind int; const (
 // Dialog is a modal dialog window.
 type Dialog struct {
 	tomo.Window
-	controlRow tomo.ContainerBox
+	controlRow *Container
 }
 
 type clickable interface {
@@ -53,6 +53,7 @@ func NewDialog (kind DialogKind, parent tomo.Window, title, message string, opti
 	case DialogError:       iconId = tomo.IconDialogError
 	}
 	dialog.SetTitle(title)
+	dialog.SetIcon(iconId)
 	icon := NewIcon(iconId, tomo.IconSizeLarge)
 	messageText := NewLabel(message)
 	messageText.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
@@ -66,7 +67,7 @@ func NewDialog (kind DialogKind, parent tomo.Window, title, message string, opti
 	dialog.controlRow.SetAlign(tomo.AlignEnd, tomo.AlignEnd)
 
 	dialog.SetRoot(NewOuterContainer (
-		layouts.NewGrid([]bool { true }, []bool { true, false }),
+		layouts.Column { true, false },
 		NewInnerContainer(layouts.ContractHorizontal, icon, messageText),
 		dialog.controlRow))
 	return dialog, nil

dropdown.go

@@ -0,0 +1,128 @@
+package objects
+
+// import "image"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+var _ tomo.Object = new(Dropdown)
+
+// Dropdown is a non-editable text input that allows the user to pick a value
+// from a list.
+type Dropdown struct {
+	box   tomo.ContainerBox
+	label *Label
+
+	value string
+	items []string
+	menu  *Menu
+
+	on struct {
+		valueChange event.FuncBroadcaster
+	}
+}
+
+// NewDropdown creates a new dropdown input with the specified items
+func NewDropdown (items ...string) *Dropdown {
+	dropdown := &Dropdown {
+		box: tomo.NewContainerBox(),
+		label:        NewLabel(""),
+	}
+	dropdown.box.SetRole(tomo.R("objects", "Dropdown"))
+	dropdown.box.SetAttr(tomo.ALayout(layouts.Row { true, false }))
+	dropdown.box.Add(dropdown.label)
+	dropdown.box.Add(NewIcon(tomo.IconListChoose, tomo.IconSizeSmall))
+	
+	dropdown.SetItems(items...)
+	if len(items) > 0 {
+		dropdown.SetValue(items[0])
+	}
+	
+	dropdown.box.SetInputMask(true)
+	dropdown.box.OnButtonDown(dropdown.handleButtonDown)
+	dropdown.box.OnButtonUp(dropdown.handleButtonUp)
+	dropdown.box.OnKeyDown(dropdown.handleKeyDown)
+	dropdown.box.OnKeyUp(dropdown.handleKeyUp)
+	dropdown.box.SetFocusable(true)
+	return dropdown
+}
+
+// GetBox returns the underlying box.
+func (this *Dropdown) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this dropdown has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *Dropdown) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// Value returns the value of the dropdown. This does not necissarily have to be
+// in the list of items.
+func (this *Dropdown) Value () string {
+	return this.value
+}
+
+// SetValue sets the value of the dropdown. This does not necissarily have to be
+// in the list of items.
+func (this *Dropdown) SetValue (value string) {
+	this.value = value
+	this.label.SetText(value)
+}
+
+// SetItems sets the items from which the user is able to pick.
+func (this *Dropdown) SetItems (items ...string) {
+	this.items = items
+}
+
+// Choose creates a menu that allows the user to pick a value.
+func (this *Dropdown) Choose () {
+	if this.menu != nil {
+		this.menu.Close()
+	}
+	menu, err := NewAnchoredMenu(this, this.itemList()...)
+	if err != nil { return }
+	this.menu = menu
+	menu.SetVisible(true)
+}
+
+func (this *Dropdown) itemList () []tomo.Object {
+	items := make([]tomo.Object, len(this.items))
+	for index, value := range this.items {
+		value := value
+		item := NewMenuItem(value)
+		item.OnClick(func () {
+			this.SetValue(value)
+			this.on.valueChange.Broadcast()
+		})
+		items[index] = item
+	}
+	return items
+}
+
+func (this *Dropdown) handleKeyDown (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
+	this.Choose()
+	return true
+}
+
+func (this *Dropdown) handleKeyUp (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
+	return true
+}
+
+func (this *Dropdown) handleButtonDown (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	return true
+}
+
+func (this *Dropdown) handleButtonUp (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
+		this.Choose()
+	}
+	return true
+}

file.go

@@ -0,0 +1,129 @@
+package objects
+
+import "time"
+import "unicode"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/data"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+var _ tomo.Object = new(File)
+
+// File is a representation of a file or directory.
+type File struct {
+	box tomo.ContainerBox
+
+	label *Label
+	icon  *MimeIcon
+	mime  data.Mime
+
+	lastClick time.Time
+
+	on struct {
+		doubleClick event.FuncBroadcaster
+	}
+}
+
+// NewFile creates a new file icon with the given name and MIME type.
+func NewFile (name string, mime data.Mime) *File {
+	file := &File {
+		box:   tomo.NewContainerBox(),
+		label: NewLabel(""),
+		icon:  NewMimeIcon(mime, tomo.IconSizeLarge),
+	}
+	file.box.SetRole(tomo.R("objects", "File"))
+	file.box.SetAttr(tomo.ALayout(layouts.ContractVertical))
+	
+	file.box.Add(file.icon)
+	file.box.Add(file.label)
+	file.box.SetAttr(tomo.AAlign(tomo.AlignMiddle, tomo.AlignStart))
+	file.label.SetAlign(tomo.AlignMiddle, tomo.AlignStart)
+	// file.label.SetOverflow(false, true)
+	// file.label.SetWrap(true)
+	file.SetType(mime)
+	file.SetName(name)
+
+	file.box.SetInputMask(true)
+	file.box.SetFocusable(true)
+	file.box.OnButtonDown(file.handleButtonDown)
+	file.box.OnButtonUp(file.handleButtonUp)
+	file.box.OnKeyDown(file.handleKeyDown)
+	file.box.OnKeyUp(file.handleKeyUp)
+	return file
+}
+
+// GetBox returns the underlying box.
+func (this *File) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this file has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *File) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// SetName sets the text of the file's label.
+func (this *File) SetName (text string) {
+	this.label.SetText(truncateText(text, 16))
+}
+
+// SetType sets the MIME type of the file.
+func (this *File) SetType (mime data.Mime) {
+	this.mime = mime
+	this.icon.SetIcon(mime, tomo.IconSizeLarge)
+}
+
+// OnDoubleClick specifies a function to be called when the file is
+// double-clicked.
+func (this *File) OnDoubleClick (callback func ()) event.Cookie {
+	return this.on.doubleClick.Connect(callback)
+}
+
+func (this *File) handleKeyDown (key input.Key, numberPad bool) bool {
+	if key != input.KeyEnter && key != input.Key(' ') { return false }
+	return true
+}
+
+func (this *File) handleKeyUp (key input.Key, numberPad bool) bool {
+	if key != input.KeyEnter && key != input.Key(' ') { return false }
+	this.on.doubleClick.Broadcast()
+	return true
+}
+
+func (this *File) handleButtonDown (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	return true
+}
+
+func (this *File) handleButtonUp (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
+		// TODO double click delay should be configurable
+		if time.Since(this.lastClick) < time.Second {
+			this.on.doubleClick.Broadcast()
+		}
+		this.lastClick = time.Now()
+	}
+	return true
+}
+
+func truncateText (text string, max int) string {
+	lastChar := -1
+	len := 0
+	for index, char := range text {
+		if !unicode.IsSpace(char) {
+			lastChar = index
+		}
+		len ++
+		if len >= max {
+			if lastChar != -1 {
+				return text[:lastChar] + "..."
+			}
+			break
+		}
+	}
+	return text
+}

go.mod

@@ -2,6 +2,4 @@ module git.tebibyte.media/tomo/objects
 
 go 1.20
 
-require git.tebibyte.media/tomo/tomo v0.36.0
-
-require golang.org/x/image v0.11.0 // indirect
+require git.tebibyte.media/tomo/tomo v0.46.1

go.sum

@@ -1,35 +1,2 @@
-git.tebibyte.media/tomo/tomo v0.36.0 h1:V9vyPYb4kpUceBhcDF/XyLDACzE5lY8kYEGHAkIsqs0=
-git.tebibyte.media/tomo/tomo v0.36.0/go.mod h1:C9EzepS9wjkTJjnZaPBh22YvVPyA4hbBAJVU20Rdmps=
-github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
-golang.org/x/image v0.11.0 h1:ds2RoQvBvYTiJkwpSFDwCcDFNX7DqjL2WsUgTNk0Ooo=
-golang.org/x/image v0.11.0/go.mod h1:bglhjqbqVuEb9e9+eNR45Jfu7D+T4Qan+NhQk8Ck2P8=
-golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
-golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
-golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
-golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
-golang.org/x/text v0.12.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
-golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+git.tebibyte.media/tomo/tomo v0.46.1 h1:/8fT6I9l4TK529zokrThbNDHGRvUsNgif1Zs++0PBSQ=
+git.tebibyte.media/tomo/tomo v0.46.1/go.mod h1:WrtilgKB1y8O2Yu7X4mYcRiqOlPR8NuUnoA/ynkQWrs=

heading.go

@@ -2,22 +2,72 @@ package objects
 
 import "fmt"
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/text"
+import "git.tebibyte.media/tomo/tomo/event"
+
+var _ tomo.Object = new(Heading)
 
 // Heading is a label that denotes the start of some section of content. It can
 // have a level from 0 to 2, with 0 being the most prominent and 2 being the
-// most subtle. The level is described in the role variation.
+// most subtle.
+//
+// Tags:
+//   - [0] The heading has a level of 0 (most prominent).
+//   - [1] The heading has a level of 1.
+//   - [2] The heading has a level of 2 (least prominent).
 type Heading struct {
-	tomo.TextBox
+	box tomo.TextBox
 }
 
 // NewHeading creates a new section heading. The level can be from 0 to 2.
 func NewHeading (level int, text string) *Heading {
 	if level < 0 { level = 0 }
 	if level > 2 { level = 2 }
-	this := &Heading { TextBox: tomo.NewTextBox() }
-	this.SetRole(tomo.R("objects", "Heading", fmt.Sprint(level)))
-	tomo.Apply(this)
+	this := &Heading { box: tomo.NewTextBox() }
+	this.box.SetRole(tomo.R("objects", "Heading"))
+	this.box.SetTag(fmt.Sprint(level), true)
 	this.SetText(text)
+	this.box.SetSelectable(true)
+	this.box.SetFocusable(true)
 	return this
 }
 
+// GetBox returns the underlying box.
+func (this *Heading) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this heading has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *Heading) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// SetText sets the text content of the heading.
+func (this *Heading) SetText (text string) {
+	this.box.SetText(text)
+}
+
+// Select sets the text cursor or selection.
+func (this *Heading) Select (dot text.Dot) {
+	this.box.Select(dot)
+}
+
+// Dot returns the text cursor or selection.
+func (this *Heading) Dot () text.Dot {
+	return this.box.Dot()
+}
+
+// OnDotChange specifies a function to be called when the text cursor or
+// selection changes.
+func (this *Heading) OnDotChange (callback func ()) event.Cookie {
+	return this.box.OnDotChange(callback)
+}
+
+// NewMenuHeading creatss a new heading for use in menus.
+func NewMenuHeading (text string) *Heading {
+	heading := NewHeading(0, text)
+	heading.box.SetTag("menu", true)
+	return heading
+}

icon.go

@@ -1,43 +1,65 @@
 package objects
 
-import "image"
 import "git.tebibyte.media/tomo/tomo"
-import "git.tebibyte.media/tomo/tomo/data"
 import "git.tebibyte.media/tomo/tomo/canvas"
 
+var _ tomo.Object = new(Icon)
+
 // Icon displays a single icon.
+//
+// Tags:
+//   - [large] The icon is large sized.
+//   - [medium] The icon is medium sized.
+//   - [small] The icon is small sized.
 type Icon struct {
-	tomo.Box
+	box  tomo.Box
+	icon tomo.Icon
+	size tomo.IconSize
+}
+
+func iconSizeString (size tomo.IconSize) string {
+	switch size {
+	case tomo.IconSizeLarge:  return "large"
+	case tomo.IconSizeMedium: return "medium"
+	default:                  return "small"
+	}
 }
 
 // NewIcon creates a new icon from an icon ID.
-func NewIcon (id tomo.Icon, size tomo.IconSize) *Icon {
+func NewIcon (icon tomo.Icon, size tomo.IconSize) *Icon {
 	this := &Icon {
-		Box: tomo.NewBox(),
+		box: tomo.NewBox(),
 	}
-	this.SetRole(tomo.R("objects", "Icon", size.String()))
-	tomo.Apply(this)
-	this.SetTexture(id.Texture(size))
+	this.box.SetRole(tomo.R("objects", "Icon"))
+	this.SetIcon(icon, size)
+	this.box.OnIconSetChange(this.handleIconSetChange)
 	return this
 }
 
-// NewMimeIcon creates a new icon from a MIME type.
-func NewMimeIcon (mime data.Mime, size tomo.IconSize) *Icon {
-	this := &Icon {
-		Box: tomo.NewBox(),
-	}
-	this.SetRole(tomo.R("objects", "Icon", size.String()))
-	tomo.Apply(this)
-	this.SetTexture(tomo.MimeIcon(mime, size))
-	return this
+// GetBox returns the underlying box.
+func (this *Icon) GetBox () tomo.Box {
+	return this.box
 }
 
-func (this *Icon) SetTexture (texture canvas.Texture) {
-	this.Box.SetTextureCenter(texture)
+// SetIcon sets the icon.
+func (this *Icon) SetIcon (icon tomo.Icon, size tomo.IconSize) {
+	if this.icon == icon { return }
+	this.icon = icon
+	this.size = size
+	this.setTexture(icon.Texture(size))
+}
+
+func (this *Icon) handleIconSetChange () {
+	this.setTexture(this.icon.Texture(this.size))
+}
+
+func (this *Icon) setTexture (texture canvas.Texture) {
+	this.box.SetAttr(tomo.ATexture(texture))
+	this.box.SetAttr(tomo.ATextureMode(tomo.TextureModeCenter))
 	if texture == nil {
-		this.SetMinimumSize(image.Pt(0, 0))
+		this.box.SetAttr(tomo.AMinimumSize(0, 0))
 	} else {
 		bounds := texture.Bounds()
-		this.SetMinimumSize(bounds.Max.Sub(bounds.Min))
+		this.box.SetAttr(tomo.AttrMinimumSize(bounds.Max.Sub(bounds.Min)))
 	}
 }

input.go

@@ -0,0 +1,19 @@
+package objects
+
+import "git.tebibyte.media/tomo/tomo/input"
+
+func isClickingKey (key input.Key) bool {
+	return key == input.KeyEnter || key == input.Key(' ')
+}
+
+func isConfirmationKey (key input.Key) bool {
+	return key == input.KeyEnter
+}
+
+func isClickingButton (button input.Button) bool {
+	return button == input.ButtonLeft
+}
+
+func isMenuButton (button input.Button) bool {
+	return button == input.ButtonLeft
+}

internal/color/color.go

@@ -0,0 +1,231 @@
+package color
+
+import "fmt"
+import "image/color"
+
+// HSV represents a color with hue, saturation, and value components. Each
+// component C is in range 0 <= C <= 1.
+type HSV struct {
+	H float64
+	S float64
+	V float64
+}
+
+// HSVA is an HSV color with an added 8-bit alpha component. The alpha component
+// ranges from 0x0000 (fully transparent) to 0xFFFF (opaque), and has no bearing
+// on the other components.
+type HSVA struct {
+	H float64
+	S float64
+	V float64
+	A uint16
+}
+
+var (
+	HSVModel  color.Model = color.ModelFunc(hsvModel)
+	HSVAModel color.Model = color.ModelFunc(hsvaModel)
+)
+
+func (hsv HSV) RGBA () (r, g, b, a uint32) {
+	// Adapted from:
+	// https://www.cs.rit.edu/~ncs/color/t_convert.html
+	
+	component := func (x float64) uint32 {
+		return uint32(float64(0xFFFF) * x)
+	}
+
+	s := clamp01(hsv.S)
+	v := clamp01(hsv.V)
+	if s == 0 {
+		light := component(v)
+		return light, light, light, 0xFFFF
+	}
+	
+	h := clamp01(hsv.H) * 360
+	sector := int(h / 60)
+	// otherwise when given 1.0 for H, sector would overflow to 6
+	if sector > 5 { sector = 5 }
+	offset := (h / 60) - float64(sector)
+	
+	p  := component(v * (1 - s))
+	q  := component(v * (1 - s * offset))
+	t  := component(v * (1 - s * (1 - offset)))
+	va := component(v)
+	
+	switch sector {
+	case 0:  return va, t,  p,  0xFFFF
+	case 1:  return q,  va, p,  0xFFFF
+	case 2:  return p,  va, t,  0xFFFF
+	case 3:  return p,  q,  va, 0xFFFF
+	case 4:  return t,  p,  va, 0xFFFF
+	default: return va, p,  q,  0xFFFF
+	}
+}
+
+func (hsva HSVA) RGBA () (r, g, b, a uint32) {
+	r, g, b, a = HSV {
+		H: hsva.H,
+		S: hsva.S,
+		V: hsva.V,
+	}.RGBA()
+	a = uint32(hsva.A)
+	// alpha premultiplication
+	r = (r * a) / 0xFFFF
+	g = (g * a) / 0xFFFF
+	b = (b * a) / 0xFFFF
+	return
+}
+
+// Canon returns the color but with the H, S, and V fields are constrained to
+// the range 0.0-1.0
+func (hsv HSV) Canon () HSV {
+	hsv.H = clamp01(hsv.H)
+	hsv.S = clamp01(hsv.S)
+	hsv.V = clamp01(hsv.V)
+	return hsv
+}
+
+// Canon returns the color but with the H, S, and V fields are constrained to
+// the range 0.0-1.0
+func (hsva HSVA) Canon () HSVA {
+	hsva.H = clamp01(hsva.H)
+	hsva.S = clamp01(hsva.S)
+	hsva.V = clamp01(hsva.V)
+	return hsva
+}
+
+func clamp01 (x float64) float64 {
+	if x > 1.0 { return 1.0 }
+	if x < 0.0 { return 0.0 }
+	return x
+}
+
+func hsvModel (c color.Color) color.Color {
+	switch c := c.(type) {
+	case HSV:  return c
+	case HSVA: return HSV { H: c.H, S: c.S, V: c.V }
+	default:
+		r, g, b, a := c.RGBA()
+		// alpha unpremultiplication
+		r = (r / a) * 0xFFFF
+		g = (g / a) * 0xFFFF
+		b = (b / a) * 0xFFFF
+		return rgbToHSV(r, g, b)
+	}
+}
+
+func hsvaModel (c color.Color) color.Color {
+	switch c := c.(type) {
+	case HSV:  return HSVA { H: c.H, S: c.S, V: c.V, A: 0xFFFF }
+	case HSVA: return c
+	default:
+		r, g, b, a := c.RGBA()
+		hsv := rgbToHSV(r, g, b)
+
+		return HSVA {
+			H: hsv.H,
+			S: hsv.S,
+			V: hsv.V,
+			A: uint16(a),
+		}
+	}
+}
+
+func rgbToHSV (r, g, b uint32) HSV {
+	// Adapted from:
+	// https://www.cs.rit.edu/~ncs/color/t_convert.html
+	
+	component := func (x uint32) float64 {
+		return clamp01(float64(x) / 0xFFFF)
+	}
+	cr := component(r)
+	cg := component(g)
+	cb := component(b)
+	
+	var maxComponent float64
+	if cr > maxComponent { maxComponent = cr }
+	if cg > maxComponent { maxComponent = cg }
+	if cb > maxComponent { maxComponent = cb }
+	var minComponent = 1.0
+	if cr < minComponent { minComponent = cr }
+	if cg < minComponent { minComponent = cg }
+	if cb < minComponent { minComponent = cb }
+	
+	hsv := HSV {
+		V: maxComponent,
+	}
+	
+	delta := maxComponent - minComponent
+	if delta == 0 {
+		// hsva.S is undefined, so hue doesn't matter
+		return hsv
+	}
+	hsv.S = delta / maxComponent
+	
+	switch {
+	case cr == maxComponent: hsv.H =     (cg - cb) / delta
+	case cg == maxComponent: hsv.H = 2 + (cb - cr) / delta
+	case cb == maxComponent: hsv.H = 4 + (cr - cg) / delta
+	}
+	
+	hsv.H *= 60
+	if hsv.H < 0 { hsv.H += 360 }
+	hsv.H /= 360
+	
+	return hsv
+}
+
+// FormatNRGBA formats an NRGBA value into a hex string.
+func FormatNRGBA (nrgba color.NRGBA) string {
+	return fmt.Sprintf("%02X%02X%02X%02X", nrgba.R, nrgba.G, nrgba.B, nrgba.A)
+}
+
+// ParseNRGBA parses an NRGBA value from a hex string. It can be of the format:
+//   - RGB
+//   - RGBA
+//   - RRGGBB
+//   - RRGGBBAA
+// If none of these are specified, this function will return an opaque black
+// color. Hex digits may either be upper case or lower case.
+func ParseNRGBA (str string) color.NRGBA {
+	runes := []rune(str)
+	c := color.NRGBA { A: 255 }
+	switch len(runes) {
+	case 3:
+		c.R = fillOctet(hexDigit(runes[0]))
+		c.G = fillOctet(hexDigit(runes[1]))
+		c.B = fillOctet(hexDigit(runes[2]))
+	case 4:
+		c.R = fillOctet(hexDigit(runes[0]))
+		c.G = fillOctet(hexDigit(runes[1]))
+		c.B = fillOctet(hexDigit(runes[2]))
+		c.A = fillOctet(hexDigit(runes[3]))
+	case 6:
+		c.R = hexOctet(runes[0], runes[1])
+		c.G = hexOctet(runes[2], runes[3])
+		c.B = hexOctet(runes[4], runes[5])
+	case 8:
+		c.R = hexOctet(runes[0], runes[1])
+		c.G = hexOctet(runes[2], runes[3])
+		c.B = hexOctet(runes[4], runes[5])
+		c.A = hexOctet(runes[6], runes[7])
+	}
+	return c
+}
+
+func hexDigit (r rune) uint8 {
+	switch {
+	case r >= '0' && r <= '9': return uint8(r - '0')
+	case r >= 'A' && r <= 'F': return uint8(r - 'A') + 10
+	case r >= 'a' && r <= 'f': return uint8(r - 'a') + 10
+	default: return 0
+	}
+}
+
+func fillOctet (low uint8) uint8 {
+	return low << 4 | low
+}
+
+func hexOctet (high, low rune) uint8 {
+	return hexDigit(high) << 4 | hexDigit(low)
+}

internal/history/history.go

@@ -0,0 +1,91 @@
+package history
+
+import "time"
+
+// History stores a stack of items, always keeping the bottom-most one. It must
+// be created using the NewHistory constructor, otherwise it will be invalid.
+type History[T comparable] struct {
+	max      int
+	stack    []T
+	topIndex int
+	topTime  time.Time
+}
+
+// NewHistory creates a new History. The initial item will be on the bottom, and
+// it will remain there until the History overflows and chooses the item after
+// it to be the initial item.
+func NewHistory[T comparable] (initial T, max int) *History[T] {
+	return &History[T] {
+		max:   max,
+		stack: []T { initial },
+	}
+}
+
+// Top returns the most recent item.
+func (this *History[T]) Top () T {
+	return this.stack[this.topIndex]
+}
+
+// Swap replaces the most recent item with another.
+func (this *History[T]) Swap (item T) {
+	this.topTime = time.Now()
+	this.SwapSilently(item)
+}
+
+// SwapSilently replaces the most recent item with another without updating the
+// time.
+func (this *History[T]) SwapSilently (item T) {
+	this.stack[this.topIndex] = item
+}
+
+// Push pushes a new item onto the stack. If the stack overflows (becomes bigger
+// than the specified max value), the initial item is removed and the one on top
+// of it takes its place.
+func (this *History[T]) Push (item T) {
+	this.topTime = time.Now()
+	if this.Top() != item {
+		this.topIndex ++
+		this.stack = append(this.stack[:this.topIndex], item)
+	}
+
+	if len(this.stack) > this.max {
+		this.stack = this.stack[1:]
+	}
+}
+
+// PushWeak replaces the most recent item if it was added recently (sooner than
+// specified by minAge), and will otherwise push the item normally. If the
+// history was popped or cleared beforehand, the item will always be pushed
+// normally. This is intended to be used for things such as keystrokes.
+func (this *History[T]) PushWeak (item T, minAge time.Duration) {
+	if time.Since(this.topTime) > minAge {
+		this.Push(item)
+	} else {
+		this.Swap(item)
+	}
+}
+
+// Redo undoes an Undo operation and returns the resulting top of the stack.
+func (this *History[T]) Redo () T {
+	if this.topIndex < len(this.stack) - 1 {
+		this.topIndex ++
+	}
+	return this.Top()
+}
+
+// Undo removes the most recent item and returns what was under it. If there is
+// only one item (the initial item), it will kept and returned.
+func (this *History[T]) Undo () T {
+	this.topTime = time.Time { }
+	if this.topIndex > 0 {
+		this.topIndex --
+	}
+	return this.Top()
+}
+
+// Clear removes all items except for the initial one.
+func (this *History[T]) Clear () {
+	this.topTime = time.Time { }
+	this.stack = this.stack[:1]
+	this.topIndex = 0
+}

label.go

@@ -1,17 +1,65 @@
 package objects
 
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/text"
+import "git.tebibyte.media/tomo/tomo/event"
+
+var _ tomo.Object = new(Label)
 
 // Label is a simple text label.
 type Label struct {
-	tomo.TextBox
+	box tomo.TextBox
 }
 
 // NewLabel creates a new text label.
 func NewLabel (text string) *Label {
-	this := &Label { TextBox: tomo.NewTextBox() }
-	this.SetRole(tomo.R("objects", "Label", ""))
-	tomo.Apply(this)
+	this := &Label { box: tomo.NewTextBox() }
+	this.box.SetRole(tomo.R("objects", "Label"))
 	this.SetText(text)
+	this.box.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
+	this.box.SetSelectable(true)
+	this.box.SetFocusable(true)
 	return this
 }
+
+// GetBox returns the underlying box.
+func (this *Label) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this label has keyboard focus. If set to true,
+// this method will steal focus away from whichever object currently has focus.
+func (this *Label) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// SetText sets the text content of the label.
+func (this *Label) SetText (text string) {
+	this.box.SetText(text)
+}
+
+// Select sets the text cursor or selection.
+func (this *Label) Select (dot text.Dot) {
+	this.box.Select(dot)
+}
+
+// Dot returns the text cursor or selection.
+func (this *Label) Dot () text.Dot {
+	return this.box.Dot()
+}
+
+// OnDotChange specifies a function to be called when the text cursor or
+// selection changes.
+func (this *Label) OnDotChange (callback func ()) event.Cookie {
+	return this.box.OnDotChange(callback)
+}
+
+// SetAlign sets the X and Y alignment of the label.
+func (this *Label) SetAlign (x, y tomo.Align) {
+	this.box.SetAttr(tomo.AAlign(x, y))
+}
+
+// SetOverflow sets the X and Y overflow of the label.
+func (this *Label) SetOverflow (x, y bool) {
+	this.box.SetAttr(tomo.AOverflow(x, y))
+}

labelcheckbox.go

@@ -5,9 +5,11 @@ import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/objects/layouts"
 
+var _ tomo.Object = new(LabelCheckbox)
+
 // LabelCheckbox is a checkbox with a label.
 type LabelCheckbox struct {
-	tomo.ContainerBox
+	box      tomo.ContainerBox
 	checkbox *Checkbox
 	label    *Label
 }
@@ -15,21 +17,44 @@ type LabelCheckbox struct {
 // NewLabelCheckbox creates a new labeled checkbox with the specified value and
 // label text.
 func NewLabelCheckbox (value bool, text string) *LabelCheckbox {
-	box := &LabelCheckbox {
-		ContainerBox: tomo.NewContainerBox(),
-		checkbox:     NewCheckbox(value),
-		label:        NewLabel(text),
+	labelCheckbox := &LabelCheckbox {
+		box:      tomo.NewContainerBox(),
+		checkbox: NewCheckbox(value),
+		label:    NewLabel(text),
 	}
-	box.SetRole(tomo.R("objects", "LabelCheckbox", ""))
-	tomo.Apply(box)
-	box.label.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
-	box.Add(box.checkbox)
-	box.Add(box.label)
-	box.SetLayout(layouts.NewGrid([]bool { false, true }, []bool { false }))
+	labelCheckbox.box.SetRole(tomo.R("objects", "LabelCheckbox"))
+	labelCheckbox.label.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
+	labelCheckbox.label.GetBox().(tomo.TextBox).SetSelectable(false)
+	labelCheckbox.label.GetBox().(tomo.TextBox).SetFocusable(false)
+	labelCheckbox.box.Add(labelCheckbox.checkbox)
+	labelCheckbox.box.Add(labelCheckbox.label)
+	labelCheckbox.box.SetAttr(tomo.ALayout(layouts.Row { false, true }))
 
-	box.OnMouseUp(box.handleMouseUp)
-	box.label.OnMouseUp(box.handleMouseUp)
-	return box
+	labelCheckbox.box.OnButtonDown(labelCheckbox.handleButtonDown)
+	labelCheckbox.box.OnButtonUp(labelCheckbox.handleButtonUp)
+	return labelCheckbox
+}
+
+// GetBox returns the underlying box.
+func (this *LabelCheckbox) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this checkbox has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *LabelCheckbox) SetFocused (focused bool) {
+	this.checkbox.SetFocused(focused)
+}
+
+// SetText sets the text label of the checkbox.
+func (this *LabelCheckbox) SetText (text string) {
+	this.label.SetText(text)
+}
+
+// Value returns the value of the checkbox.
+func (this *LabelCheckbox) Value () bool {
+	return this.checkbox.Value()
 }
 
 // SetValue sets the value of the checkbox.
@@ -42,21 +67,22 @@ func (this *LabelCheckbox) Toggle () {
 	this.checkbox.Toggle()
 }
 
-// Value returns the value of the checkbox.
-func (this *LabelCheckbox) Value () bool {
-	return this.checkbox.Value()
-}
-
-// OnValueChange specifies a function to be called when the checkbox's value
-// changes.
+// OnValueChange specifies a function to be called when the user checks or
+// unchecks the checkbox.
 func (this *LabelCheckbox) OnValueChange (callback func ()) event.Cookie {
 	return this.checkbox.OnValueChange(callback)
 }
 
-func (this *LabelCheckbox) handleMouseUp (button input.Button) {
-	if button != input.ButtonLeft { return }
-	if this.MousePosition().In(this.Bounds()) {
+func (this *LabelCheckbox) handleButtonDown (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	return true
+}
+
+func (this *LabelCheckbox) handleButtonUp (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.checkbox.SetFocused(true)
 		this.checkbox.Toggle()
 	}
+	return true
 }

labelswatch.go

@@ -0,0 +1,96 @@
+package objects
+
+import "image/color"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+var _ tomo.Object = new(LabelSwatch)
+
+// LabelSwatch is a swatch with a label.
+type LabelSwatch struct {
+	box    tomo.ContainerBox
+	swatch *Swatch
+	label  *Label
+}
+
+// NewLabelSwatch creates a new labeled swatch with the specified color and
+// label text.
+func NewLabelSwatch (value color.Color, text string) *LabelSwatch {
+	labelSwatch := &LabelSwatch {
+		box:    tomo.NewContainerBox(),
+		swatch: NewSwatch(value),
+		label:  NewLabel(text),
+	}
+	labelSwatch.box.SetRole(tomo.R("objects", "LabelSwatch"))
+	labelSwatch.swatch.label = text
+	labelSwatch.label.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
+	labelSwatch.label.GetBox().(tomo.TextBox).SetSelectable(false)
+	labelSwatch.label.GetBox().(tomo.TextBox).SetFocusable(false)
+	labelSwatch.box.Add(labelSwatch.swatch)
+	labelSwatch.box.Add(labelSwatch.label)
+	labelSwatch.box.SetAttr(tomo.ALayout(layouts.Row { false, true }))
+
+	labelSwatch.box.OnButtonDown(labelSwatch.handleButtonDown)
+	labelSwatch.box.OnButtonUp(labelSwatch.handleButtonUp)
+	return labelSwatch
+}
+
+// GetBox returns the underlying box.
+func (this *LabelSwatch) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this swatch has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *LabelSwatch) SetFocused (focused bool) {
+	this.swatch.SetFocused(focused)
+}
+
+// SetText sets the text label of the swatch.
+func (this *LabelSwatch) SetText (text string) {
+	this.label.SetText(text)
+}
+
+// Value returns the color of the swatch.
+func (this *LabelSwatch) Value () color.Color {
+	return this.swatch.Value()
+}
+
+// SetValue sets the color of the swatch.
+func (this *LabelSwatch) SetValue (value color.Color) {
+	this.swatch.SetValue(value)
+}
+
+// OnValueChange specifies a function to be called when the swatch's color
+// is changed by the user.
+func (this *LabelSwatch) OnValueChange (callback func ()) event.Cookie {
+	return this.swatch.OnValueChange(callback)
+}
+
+// RGBA satisfies the color.Color interface
+func (this *LabelSwatch) RGBA () (r, g, b, a uint32) {
+	return this.swatch.RGBA()
+}
+
+// OnConfirm specifies a function to be called when the user selects "OK" in the
+// color picker.
+func (this *LabelSwatch) OnConfirm (callback func ()) event.Cookie {
+	return this.swatch.OnConfirm(callback)
+}
+
+func (this *LabelSwatch) handleButtonDown (button input.Button) bool {
+	if !isClickingButton(button) { return true }
+	return true
+}
+
+func (this *LabelSwatch) handleButtonUp (button input.Button) bool {
+	if !isClickingButton(button) { return true }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
+		this.swatch.SetFocused(true)
+		this.swatch.Choose()
+	}
+	return true
+}

layouts/contract.go

@@ -0,0 +1,40 @@
+package layouts
+
+import "image"
+import "git.tebibyte.media/tomo/tomo"
+
+var _ tomo.Layout = ContractVertical
+
+// Contract is a layout that arranges boxes in a simple row or column according
+// to their minimum sizes.
+type Contract bool
+
+// ContractVertical is a vertical contracted layout.
+const ContractVertical Contract = true
+
+// ContractHorizontal is a horizontal contracted layout.
+const ContractHorizontal Contract = false
+
+func (contract Contract) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
+	return contract.fallback().MinimumSize(hints, boxes)
+}
+
+func (contract Contract) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
+	contract.fallback().Arrange(hints, boxes)
+}
+
+func (contract Contract) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	return contract.fallback().RecommendedHeight(hints, boxes, width)
+}
+
+func (contract Contract) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	return contract.fallback().RecommendedWidth(hints, boxes, height)
+}
+
+func (contract Contract) fallback () tomo.Layout {
+	if contract == ContractVertical {
+		return Column { }
+	} else {
+		return Row { }
+	}
+}

layouts/cut.go

@@ -1,173 +0,0 @@
-package layouts
-
-import "image"
-import "git.tebibyte.media/tomo/tomo"
-
-// Cut is a layout that can be divided into smaller and smaller sections.
-type Cut struct {
-	branches []*Cut
-	expand   []bool
-	vertical bool
-}
-
-// NewCut creates and returns a new Cut layout.
-func NewCut () *Cut {
-	return new(Cut)
-}
-
-// Vertical divides the layout vertically. Sections are specified using
-// booleans. If a section is true, it will expand. If false, it will contract.
-func (this *Cut) Vertical (expand ...bool) {
-	this.expand   = expand
-	this.vertical = true
-	this.fill()
-}
-
-// Horizontal divides the layout horizontally. Sections are specified using
-// booleans. If a section is true, it will expand. If false, it will contract.
-func (this *Cut) Horizontal (expand ...bool) {
-	this.expand   = expand
-	this.vertical = false
-	this.fill()
-}
-
-// At returns the section of this layout at the specified index.
-func (this *Cut) At (index int) *Cut {
-	return this.branches[index]
-}
-
-func (this *Cut) real () bool {
-	return this != nil && this.branches != nil
-}
-
-func (this *Cut) fill () {
-	this.branches = make([]*Cut, len(this.expand))
-	for index := range this.branches {
-		this.branches[index] = new(Cut)
-	}
-}
-
-func (this *Cut) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
-	size, _ := this.minimumSize(hints, boxes)
-	return size
-}
-
-func (this *Cut) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
-	this.arrange(hints, boxes)
-}
-
-func (this *Cut) minimumSize (hints tomo.LayoutHints, boxes []tomo.Box) (image.Point, []tomo.Box) {
-	size := image.Point { }
-
-	for index, branch := range this.branches {
-		if len(boxes) == 0 { break }
-
-		var point image.Point
-		if branch.real() {
-			point, boxes = branch.minimumSize(hints, boxes)
-		} else {
-			point = boxes[0].MinimumSize()
-			boxes = boxes[1:]
-		}
-
-		if this.vertical {
-			if point.X > size.X { size.X  = point.X     }
-			if index   > 0      { size.Y += hints.Gap.Y }
-			size.Y += point.Y
-		} else {
-			if point.Y > size.Y { size.Y  = point.Y     }
-			if index   > 0      { size.X += hints.Gap.X }
-			size.X += point.X
-		}
-	}
-
-	return size, boxes
-}
-
-func (this *Cut) arrange (hints tomo.LayoutHints, boxes []tomo.Box) []tomo.Box {
-	nChildren := len(this.branches)
-
-	// collect minimum sizes and physical endpoints
-	var minimums = make([]image.Point,  nChildren)
-	var leaves   = make([]tomo.Box,     nChildren)
-	var nBranches int
-	remaining := boxes
-	for index, branch := range this.branches {
-		if branch.real() {
-			minimums[index], remaining = branch.minimumSize(hints, remaining)
-		} else {
-			if len(remaining) == 0 { break }
-			leaves[index]   = remaining[0]
-			minimums[index] = remaining[0].MinimumSize()
-			remaining       = remaining[1:]
-		}
-		nBranches ++
-	}
-
-	// determine the amount of space to divide among expanding branches
-	gaps := nBranches - 1
-	var freeSpace float64; if this.vertical {
-		freeSpace = float64(hints.Bounds.Dy() - hints.Gap.Y * gaps)
-	} else {
-		freeSpace = float64(hints.Bounds.Dx() - hints.Gap.X * gaps)
-	}
-	var nExpanding float64
-	for index, minimum := range minimums {
-		if this.expand[index] {
-			nExpanding ++
-		} else if this.vertical {
-			freeSpace -= float64(minimum.Y)
-		} else {
-			freeSpace -= float64(minimum.X)
-		}
-	}
-	expandingSize := freeSpace / nExpanding
-
-	// calculate the size and position of branches
-	var bounds = make([]image.Rectangle, nChildren)
-	x := float64(hints.Bounds.Min.X)
-	y := float64(hints.Bounds.Min.Y)
-	for index, minimum := range minimums {
-		// get size along significant axis
-		var size float64; if this.expand[index] {
-			size = expandingSize
-		} else if this.vertical {
-			size = float64(minimum.Y)
-		} else {
-			size = float64(minimum.X)
-		}
-
-		// figure out bounds from size
-		if this.vertical {
-			bounds[index].Max = image.Pt (
-				int(hints.Bounds.Dx()),
-				int(size))
-		} else {
-			bounds[index].Max = image.Pt (
-				int(size),
-				int(hints.Bounds.Dy()))
-		}
-		bounds[index] = bounds[index].Add(image.Pt(int(x), int(y)))
-
-		// move along
-		if this.vertical {
-			y += float64(hints.Gap.Y) + size
-		} else {
-			x += float64(hints.Gap.X) + size
-		}
-	}
-
-	// apply the size and position
-	for index, bound := range bounds {
-		if leaves[index] != nil {
-			leaves[index].SetBounds(bound)
-			boxes = boxes[1:]
-		} else if this.branches[index] != nil {
-			newHints := hints
-			newHints.Bounds = bound
-			boxes = this.branches[index].arrange(newHints, boxes)
-		}
-	}
-	
-	return boxes
-}

layouts/flow.go

@@ -3,6 +3,8 @@ package layouts
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Layout = FlowVertical
+
 // Flow is a grid layout where the number of rows and columns changes depending
 // on the size of the container. It is designed to be used with an overflowing
 // container. If the container does not overflow in the correct direction, the
@@ -15,42 +17,43 @@ const FlowVertical Flow = true
 // FlowHorizontal is a horizontal flow layout.
 const FlowHorizontal Flow = false
 
-func (flow Flow) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
+func (flow Flow) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
 	// TODO: write down somewhere that layout minimums aren't taken into
 	// account when the respective direction is overflowed
 	return flow.fallback().MinimumSize(hints, boxes)
 }
 
-func (flow Flow) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
+func (flow Flow) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
 	if flow.v() && !hints.OverflowY || flow.h() && !hints.OverflowX {
 		flow.fallback().Arrange(hints, boxes)
 	}
 
 	// find a minor size value that will fit all boxes
 	minorSize := 0
-	for _, box := range boxes {
-		boxSize := flow.minor(box.MinimumSize())
+	for index := 0; index < boxes.Len(); index ++ {
+		boxSize := flow.minor(boxes.MinimumSize(index))
 		if boxSize > minorSize { minorSize = boxSize }
 	}
 	if minorSize == 0 { return }
 	minorSteps :=
 		(flow.deltaMinor(hints.Bounds) + flow.minor(hints.Gap)) /
 		(minorSize + flow.minor(hints.Gap))
+	if minorSteps < 1 { minorSteps = 1 }
 
 	// arrange
 	point := hints.Bounds.Min
 	index := 0
-	for index < len(boxes) {
+	for index < boxes.Len() {
 		// get a slice of boxes for this major step
-		stepIndexEnd := index + minorSteps
-		if stepIndexEnd > len(boxes) { stepIndexEnd = len(boxes) }
-		step := boxes[index:stepIndexEnd]
+		stepIndexStart := index
+		stepIndexEnd   := index + minorSteps
+		if stepIndexEnd > boxes.Len() { stepIndexEnd = boxes.Len() }
 		index += minorSteps
 		
 		// find a major size that will fit all boxes on this major step
 		majorSize := 0
-		for _, box := range step {
-			boxSize := flow.major(box.MinimumSize())
+		for index := stepIndexStart; index < stepIndexEnd; index ++ {
+			boxSize := flow.major(boxes.MinimumSize(index))
 			if boxSize > majorSize { majorSize = boxSize }
 		}
 		if majorSize == 0 { continue }
@@ -59,9 +62,9 @@ func (flow Flow) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
 		var size image.Point
 		size = flow.incrMajor(size, majorSize)
 		size = flow.incrMinor(size, minorSize)
-		for _, box := range step {
+		for index := stepIndexStart; index < stepIndexEnd; index ++ {
 			bounds := image.Rectangle { Min: point, Max: point.Add(size) }
-			box.SetBounds(bounds)
+			boxes.SetBounds(index, bounds)
 
 			point = flow.incrMinor(point, minorSize + flow.minor(hints.Gap))
 		}
@@ -121,3 +124,13 @@ func (flow Flow) deltaMinor (rectangle image.Rectangle) int {
 func (flow Flow) fallback () tomo.Layout {
 	return Contract(flow)
 }
+
+func (flow Flow) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	// TODO
+	return 0
+}
+
+func (flow Flow) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	// TODO
+	return 0
+}

layouts/grid.go

@@ -4,6 +4,8 @@ import "math"
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Layout = new(Grid)
+
 // Grid is a layout that arranges boxes in a grid formation with distinct rows
 // and columns. It is great for creating forms.
 type Grid struct {
@@ -16,15 +18,21 @@ type Grid struct {
 // will contract. Boxes are laid out left to right, then top to bottom. Boxes
 // that go beyond the lengh of rows will be laid out according to columns, but
 // they will not expand vertically.
-func NewGrid (columns, rows []bool) *Grid {
-	this := &Grid {
-		xExpand: columns,
-		yExpand: rows,
+//
+// If you aren't sure how to use this constructor, here is an example:
+//
+//            X0     X1    X2     Y0    Y1    Y2
+//   NewGrid(true, false, true)(false, true, true)
+func NewGrid (columns ...bool) func (rows ...bool) *Grid {
+	return func (rows ...bool) *Grid {
+		return &Grid {
+			xExpand: columns,
+			yExpand: rows,
+		}
 	}
-	return this
 }
 
-func (this *Grid) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
+func (this *Grid) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
 	cols, rows := this.minimums(boxes)
 	size := image.Pt (
 		(len(cols) - 1) * hints.Gap.X,
@@ -34,7 +42,7 @@ func (this *Grid) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.P
 	return size
 }
 
-func (this *Grid) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
+func (this *Grid) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
 	xExpand := func (index int) bool {
 		return this.xExpand[index]
 	}
@@ -48,9 +56,9 @@ func (this *Grid) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
 	expand(hints, rows, hints.Bounds.Dy(), yExpand)
 
 	position := hints.Bounds.Min
-	for index, box := range boxes {
+	for index := 0; index < boxes.Len(); index ++ {
 		col, row := index % len(cols), index / len(cols)
-		box.SetBounds(image.Rectangle {
+		boxes.SetBounds(index, image.Rectangle {
 			Min: position,
 			Max: position.Add(image.Pt(cols[col], rows[row])),
 		})
@@ -63,13 +71,13 @@ func (this *Grid) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
 	}
 }
 
-func (this *Grid) minimums (boxes []tomo.Box) ([]int, []int) {
+func (this *Grid) minimums (boxes tomo.BoxQuerier) ([]int, []int) {
 	nCols, nRows := this.dimensions(boxes)
 	cols,  rows  := make([]int, nCols), make([]int, nRows)
 
-	for index, box := range boxes {
+	for index := 0; index < boxes.Len(); index ++ {
 		col, row := index % len(cols), index / len(cols)
-		minimum := box.MinimumSize()
+		minimum := boxes.MinimumSize(index)
 		if cols[col] < minimum.X {
 			cols[col] = minimum.X
 		}
@@ -81,8 +89,8 @@ func (this *Grid) minimums (boxes []tomo.Box) ([]int, []int) {
 	return cols, rows
 }
 
-func (this *Grid) dimensions (boxes []tomo.Box) (int, int) {
-	return len(this.xExpand), ceilDiv(len(boxes), len(this.xExpand)) 
+func (this *Grid) dimensions (boxes tomo.BoxQuerier) (int, int) {
+	return len(this.xExpand), ceilDiv(boxes.Len(), len(this.xExpand)) 
 }
 
 func expand (hints tomo.LayoutHints, sizes []int, space int, expands func (int) bool) {
@@ -104,5 +112,14 @@ func expand (hints tomo.LayoutHints, sizes []int, space int, expands func (int)
 }
 
 func ceilDiv (x, y int) int {
+	if y == 0 { return 0 }
 	return int(math.Ceil(float64(x) / float64(y)))
 }
+
+func (this *Grid) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	return this.MinimumSize(hints, boxes).Y
+}
+
+func (this *Grid) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	return this.MinimumSize(hints, boxes).X
+}

layouts/layouts.go

@@ -1,95 +0,0 @@
-package layouts
-
-import "image"
-import "git.tebibyte.media/tomo/tomo"
-
-// Contract is a layout that arranges boxes in a simple row or column according
-// to their minimum sizes.
-type Contract bool
-
-// ContractVertical is a vertical contracted layout.
-const ContractVertical Contract = true
-
-// ContractHorizontal is a horizontal contracted layout.
-const ContractHorizontal Contract = false
-
-func (contract Contract) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
-	if contract.v() {
-		dot := image.Point { }
-		for _, box := range boxes {
-			minimum := box.MinimumSize()
-			dot.Y += minimum.Y
-			if dot.X < minimum.X {
-				dot.X = minimum.X
-			}
-		}
-		dot.Y += hints.Gap.Y * (len(boxes) - 1)
-		return dot
-	} else {
-		dot := image.Point { }
-		for _, box := range boxes {
-			minimum := box.MinimumSize()
-			dot.X += minimum.X
-			if dot.Y < minimum.Y {
-				dot.Y = minimum.Y
-			}
-		}
-		dot.X += hints.Gap.X * (len(boxes) - 1)
-		return dot
-	}
-}
-
-func (contract Contract) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
-	if contract.v() {
-		dot := hints.Bounds.Min
-		for index, box := range boxes {
-			if index > 0 { dot.Y += hints.Gap.Y }
-			minimum := box.MinimumSize()
-			box.SetBounds(image.Rectangle {
-				Min: dot,
-				Max: dot.Add(image.Pt(hints.Bounds.Dx(), minimum.Y)),
-			})
-			dot.Y += minimum.Y
-		}
-		
-		height := dot.Y - hints.Bounds.Min.Y
-		offset := 0
-		
-		switch hints.AlignY {
-		case tomo.AlignMiddle:
-			offset = (hints.Bounds.Dy() - height) / 2
-		case tomo.AlignEnd:
-			offset = hints.Bounds.Dy() - height
-		}
-		for _, box := range boxes {
-			box.SetBounds(box.Bounds().Add(image.Pt(0, offset)))
-		}
-	} else {
-		dot := hints.Bounds.Min
-		for index, box := range boxes {
-			if index > 0 { dot.X += hints.Gap.X }
-			minimum := box.MinimumSize()
-			box.SetBounds(image.Rectangle {
-				Min: dot,
-				Max: dot.Add(image.Pt(minimum.X, hints.Bounds.Dy())),
-			})
-			dot.X += minimum.X
-		}
-
-		width  := dot.X - hints.Bounds.Min.X
-		offset := 0
-		
-		switch hints.AlignX {
-		case tomo.AlignMiddle:
-			offset = (hints.Bounds.Dx() - width) / 2
-		case tomo.AlignEnd:
-			offset = hints.Bounds.Dx() - width
-		}
-		for _, box := range boxes {
-			box.SetBounds(box.Bounds().Add(image.Pt(offset, 0)))
-		}
-	}
-}
-
-func (contract Contract) v () bool { return contract == ContractVertical   }
-func (contract Contract) h () bool { return contract == ContractHorizontal }

layouts/rowcol.go

@@ -0,0 +1,220 @@
+package layouts
+
+import "image"
+import "git.tebibyte.media/tomo/tomo"
+
+var _ tomo.Layout = ContractVertical
+
+// Row arranges boxes in a row. Boxes that share an index with a true value will
+// expand, and others will contract.
+type Row []bool
+
+// Column arranges boxes in a column. Boxes that share an index with a true
+// value will expand, and others will contract.
+type Column []bool
+
+func (column Column) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
+	dot := image.Point { }
+	for index := 0; index < boxes.Len(); index ++ {
+		minimum := boxes.MinimumSize(index)
+		dot.Y += minimum.Y
+		if dot.X < minimum.X {
+			dot.X = minimum.X
+		}
+	}
+	dot.Y += hints.Gap.Y * (boxes.Len() - 1)
+	return dot
+}
+
+func (row Row) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
+	dot := image.Point { }
+	for index := 0; index < boxes.Len(); index ++ {
+		minimum := boxes.MinimumSize(index)
+		dot.X += minimum.X
+		if dot.Y < minimum.Y {
+			dot.Y = minimum.Y
+		}
+	}
+	dot.X += hints.Gap.X * (boxes.Len() - 1)
+	return dot
+}
+
+func (column Column) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
+	expands := func (index int) bool {
+		if index >= len(column) { return false }
+		return column[index]
+	}
+
+	// determine expanding box size
+	expandingSize := 0.0
+	if !hints.OverflowY {
+		gaps       := boxes.Len() - 1
+		freeSpace  := float64(hints.Bounds.Dy() - hints.Gap.Y * gaps)
+		nExpanding := 0
+		for index := 0; index < boxes.Len(); index ++ {
+			if expands(index) {
+				nExpanding ++
+			} else {
+				freeSpace -= float64(boxes.MinimumSize(index).Y)
+			}
+		}
+		expandingSize = freeSpace / float64(nExpanding)
+	}
+
+	// determine width
+	width := 0
+	if hints.OverflowX {
+		for index := 0; index < boxes.Len(); index ++ {
+			minimum := boxes.MinimumSize(index)
+			if width < minimum.X { width = minimum.X }
+		}
+	} else {
+		width = hints.Bounds.Dx()
+	}
+
+	// arrange
+	dot := hints.Bounds.Min
+	bounds := make([]image.Rectangle, boxes.Len())
+	for index := 0; index < boxes.Len(); index ++ {
+		if index > 0 { dot.Y += hints.Gap.Y }
+
+		// determine height
+		height := boxes.MinimumSize(index).Y
+		if hints.OverflowY {
+			height = boxes.RecommendedHeight(index, width)
+		} else {
+			if expands(index) {
+				height = int(expandingSize)
+			}
+		}
+
+		// store bounds of this box
+		bounds[index] = image.Rectangle {
+			Min: dot,
+			Max: dot.Add(image.Pt(width, height)),
+		}
+		dot.Y += height
+	}
+
+	// align
+	height := dot.Y - hints.Bounds.Min.Y
+	offset := 0
+	switch hints.AlignY {
+	case tomo.AlignMiddle:
+		offset = (hints.Bounds.Dy() - height) / 2
+	case tomo.AlignEnd:
+		offset = hints.Bounds.Dy() - height
+	}
+	for index := 0; index < boxes.Len(); index ++ {
+		boxes.SetBounds(index, bounds[index].Add(image.Pt(0, offset)))
+	}
+}
+
+func (row Row) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
+	expands := func (index int) bool {
+		if index >= len(row) { return false }
+		return row[index]
+	}
+
+	// determine expanding box size
+	expandingSize := 0.0
+	if !hints.OverflowY {
+		gaps       := boxes.Len() - 1
+		freeSpace  := float64(hints.Bounds.Dx() - hints.Gap.X * gaps)
+		nExpanding := 0
+		for index := 0; index < boxes.Len(); index ++ {
+			if expands(index) {
+				nExpanding ++
+			} else {
+				freeSpace -= float64(boxes.MinimumSize(index).X)
+			}
+		}
+		expandingSize = freeSpace / float64(nExpanding)
+	}
+
+	// determine height
+	height := 0
+	if hints.OverflowY {
+		for index := 0; index < boxes.Len(); index ++ {
+			minimum := boxes.MinimumSize(index)
+			if height < minimum.Y { height = minimum.Y }
+		}
+	} else {
+		height = hints.Bounds.Dy()
+	}
+
+	// arrange
+	dot := hints.Bounds.Min
+	bounds := make([]image.Rectangle, boxes.Len())
+	for index := 0; index < boxes.Len(); index ++ {
+		if index > 0 { dot.X += hints.Gap.X }
+
+		// determine width
+		width := boxes.MinimumSize(index).X
+		if hints.OverflowY {
+			width = boxes.RecommendedHeight(index, height)
+		} else {
+			if expands(index) {
+				width = int(expandingSize)
+			}
+		}
+
+		// store bounds
+		bounds[index] = image.Rectangle {
+			Min: dot,
+			Max: dot.Add(image.Pt(width, height)),
+		}
+		dot.X += width
+	}
+
+	// align
+	width  := dot.X - hints.Bounds.Min.X
+	offset := 0
+	switch hints.AlignX {
+	case tomo.AlignMiddle:
+		offset = (hints.Bounds.Dx() - width) / 2
+	case tomo.AlignEnd:
+		offset = hints.Bounds.Dx() - width
+	}
+	for index := 0; index < boxes.Len(); index ++ {
+		boxes.SetBounds(index, bounds[index].Add(image.Pt(offset, 0)))
+	}
+}
+
+func (column Column) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	height := 0
+	for index := 0; index < boxes.Len(); index ++ {
+		height += boxes.RecommendedHeight(index, width)
+	}
+	height += hints.Gap.Y * (boxes.Len() - 1)
+	return height
+}
+
+func (row Row) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	height := 0
+	for index := 0; index < boxes.Len(); index ++ {
+		minimum   := boxes.MinimumSize(index)
+		boxHeight := boxes.RecommendedHeight(index, minimum.X)
+		if boxHeight > height { height = boxHeight }
+	}
+	return height
+}
+
+func (column Column) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	width := 0
+	for index := 0; index < boxes.Len(); index ++ {
+		minimum  := boxes.MinimumSize(index)
+		boxWidth := boxes.RecommendedWidth(index, minimum.Y)
+		if boxWidth > width { width = boxWidth }
+	}
+	return width
+}
+
+func (row Row) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	width := 0
+	for index := 0; index < boxes.Len(); index ++ {
+		width += boxes.RecommendedWidth(index, height)
+	}
+	width += hints.Gap.X * (boxes.Len() - 1)
+	return width
+}

menu.go

@@ -7,52 +7,48 @@ import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/objects/layouts"
 
 // Menu is a menu window.
+//
+// Sub-components:
+//   - TearLine is a horizontal line at the top of the menu that, when clicked,
+//     causes the menu to be "torn off" into a movable window.
 type Menu struct {
 	tomo.Window
 
 	parent        tomo.Window
 	bounds        image.Rectangle
 	rootContainer tomo.ContainerBox
-	tearLine      tomo.Box
+	tearLine      tomo.Object
 	torn          bool
 }
 
 // NewMenu creates a new menu with the specified items. The menu will appear
-// directly under the anchor Object. If the anchor is nil, it will appear
-// directly under the mouse pointer instead.
-func NewMenu (anchor tomo.Object, items ...tomo.Object) (*Menu, error) {
-	menu := &Menu { }
-	if anchor == nil {
-		// TODO: *actually* put it under the mouse
-		window, err := tomo.NewWindow(menu.bounds)
-		if err != nil { return nil, err }
-		menu.Window = window
-	} else {
-		menu.bounds = menuBoundsFromAnchor(anchor)
-		menu.parent = anchor.GetBox().Window()
-		window, err := menu.parent.NewMenu(menu.bounds)
-		if err != nil { return nil, err }
-		menu.Window = window
-	}
+// directly under the mouse pointer.
+func NewMenu (parent tomo.Window, items ...tomo.Object) (*Menu, error) {
+	bounds := (image.Rectangle { }).Add(parent.MousePosition())
+	return newMenu(parent, bounds, items...)
+}
 
+// NewAnchoredMenu creates a new menu with the specified items. The menu will
+// appear directly under the anchor.
+func NewAnchoredMenu (anchor tomo.Object, items ...tomo.Object) (*Menu, error) {
+	parent := anchor.GetBox().Window()
+	bounds := menuBoundsFromAnchor(anchor)
+	return newMenu(parent, bounds, items...)
+}
+
+func newMenu (parent tomo.Window, bounds image.Rectangle, items ...tomo.Object) (*Menu, error) {
+	menu := &Menu { }
+	menu.bounds = bounds
+	menu.parent = parent
+	window, err := menu.parent.NewMenu(menu.bounds)
+	if err != nil { return nil, err }
+	menu.Window = window
+	
 	menu.rootContainer = tomo.NewContainerBox()
-	menu.rootContainer.SetLayout(layouts.ContractVertical)
+	menu.rootContainer.SetAttr(tomo.ALayout(layouts.ContractVertical))
 
 	if !menu.torn {
-		menu.tearLine = tomo.NewBox()
-		menu.tearLine.SetRole(tomo.R("objects", "TearLine", ""))
-		tomo.Apply(menu.tearLine)
-		menu.tearLine.SetFocusable(true)
-		menu.tearLine.OnKeyUp(func (key input.Key, numberPad bool) {
-			if key != input.KeyEnter && key != input.Key(' ') { return }
-			menu.TearOff()
-		})
-		menu.tearLine.OnMouseUp(func (button input.Button) {
-			if button != input.ButtonLeft { return }
-			if menu.tearLine.MousePosition().In(menu.tearLine.Bounds()) {
-				menu.TearOff()
-			}
-		})
+		menu.tearLine = menu.newTearLine()
 		menu.rootContainer.Add(menu.tearLine)
 	}
 	
@@ -66,8 +62,8 @@ func NewMenu (anchor tomo.Object, items ...tomo.Object) (*Menu, error) {
 			})
 		}
 	}
-	menu.rootContainer.SetRole(tomo.R("objects", "Container", "menu"))
-	tomo.Apply(menu.rootContainer)
+	menu.rootContainer.SetRole(tomo.R("objects", "Container"))
+	menu.rootContainer.SetTag("menu", true)
 
 	menu.Window.SetRoot(menu.rootContainer)
 	return menu, nil
@@ -80,6 +76,7 @@ func (this *Menu) TearOff () {
 	this.torn = true
 
 	window, err := this.parent.NewChild(this.bounds)
+	window.SetIcon(tomo.IconListChoose)
 	if err != nil { return }
 
 	visible := this.Window.Visible()
@@ -87,12 +84,46 @@ func (this *Menu) TearOff () {
 	this.Window.Close()
 
 	this.rootContainer.Remove(this.tearLine)
+	this.rootContainer.SetTag("torn", true)
 	
 	this.Window = window
 	this.Window.SetRoot(this.rootContainer)
 	this.Window.SetVisible(visible)
 }
 
+func (this *Menu) newTearLine () tomo.Object {
+	tearLine := tomo.NewBox()
+	tearLine.SetRole(tomo.R("objects", "TearLine"))
+	tearLine.SetFocusable(true)
+	tearLine.OnMouseEnter(func () {
+		tearLine.SetFocused(true)
+	})
+	tearLine.OnMouseLeave(func () {
+		tearLine.SetFocused(false)
+	})
+	tearLine.OnKeyDown(func (key input.Key, numberPad bool) bool {
+		if !isClickingKey(key) { return false }
+		return true
+	})
+	tearLine.OnKeyUp(func (key input.Key, numberPad bool) bool {
+		if !isClickingKey(key) { return false }
+		this.TearOff()
+		return true
+	})
+	tearLine.OnButtonDown(func (button input.Button) bool {
+		if !isClickingButton(button) { return false }
+		return true
+	})
+	tearLine.OnButtonUp(func (button input.Button) bool {
+		if !isClickingButton(button) { return false }
+		if tearLine.Window().MousePosition().In(tearLine.Bounds()) {
+			this.TearOff()
+		}
+		return true
+	})
+	return tearLine
+}
+
 func menuBoundsFromAnchor (anchor tomo.Object) image.Rectangle {
 	bounds := anchor.GetBox().Bounds()
 	return image.Rect (

menuitem.go

@@ -5,12 +5,14 @@ import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/objects/layouts"
 
-// MenuItem is a clickable button.
-type MenuItem struct {
-	tomo.ContainerBox
+var _ tomo.Object = new(MenuItem)
 
-	label *Label
-	icon  *Icon
+// MenuItem is a selectable memu item.
+type MenuItem struct {
+	box tomo.ContainerBox
+
+	label       *Label
+	icon        *Icon
 	labelActive bool
 	
 	on struct {
@@ -20,28 +22,44 @@ type MenuItem struct {
 
 // NewMenuItem creates a new menu item with the specified text.
 func NewMenuItem (text string) *MenuItem {
-	box := &MenuItem {
-		ContainerBox: tomo.NewContainerBox(),
-		label:        NewLabel(text),
-		icon:         NewIcon("", tomo.IconSizeSmall),
+	return NewIconMenuItem(tomo.IconUnknown, text)
+}
+
+// NewIconMenuItem creates a new menu item with the specified icon and text.
+func NewIconMenuItem (icon tomo.Icon, text string) *MenuItem {
+	menuItem := &MenuItem {
+		box:   tomo.NewContainerBox(),
+		label: NewLabel(text),
+		icon:  NewIcon(icon, tomo.IconSizeSmall),
 	}
-	box.SetRole(tomo.R("objects", "MenuItem", ""))
-	tomo.Apply(box)
-	box.label.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
-	box.SetLayout(layouts.NewGrid([]bool { false, true }, []bool { true }))
+	menuItem.box.SetRole(tomo.R("objects", "MenuItem"))
+	menuItem.label.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
+	menuItem.box.SetAttr(tomo.ALayout(layouts.Row { false, true }))
 	
-	box.Add(box.icon)
-	box.Add(box.label)
+	menuItem.box.Add(menuItem.icon)
+	menuItem.box.Add(menuItem.label)
 	
-	box.CaptureDND(true)
-	box.CaptureMouse(true)
-	box.CaptureScroll(true)
-	box.CaptureKeyboard(true)
-	
-	box.OnMouseUp(box.handleMouseUp)
-	box.OnKeyUp(box.handleKeyUp)
-	box.SetFocusable(true)
-	return box
+	menuItem.box.SetInputMask(true)
+	menuItem.box.OnMouseEnter(menuItem.handleMouseEnter)
+	menuItem.box.OnMouseLeave(menuItem.handleMouseLeave)
+	menuItem.box.OnButtonDown(menuItem.handleButtonDown)
+	menuItem.box.OnButtonUp(menuItem.handleButtonUp)
+	menuItem.box.OnKeyDown(menuItem.handleKeyDown)
+	menuItem.box.OnKeyUp(menuItem.handleKeyUp)
+	menuItem.box.SetFocusable(true)
+	return menuItem
+}
+
+// GetBox returns the underlying box.
+func (this *MenuItem) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this menu item has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *MenuItem) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
 }
 
 // SetText sets the text of the items's label.
@@ -52,8 +70,7 @@ func (this *MenuItem) SetText (text string) {
 // SetIcon sets an icon for this item. Setting the icon to IconUnknown will
 // remove it.
 func (this *MenuItem) SetIcon (id tomo.Icon) {
-	if this.icon != nil { this.Remove(this.icon) }
-	this.Insert(NewIcon(id, tomo.IconSizeSmall), this.label)
+	this.icon.SetIcon(id, tomo.IconSizeSmall)
 }
 
 // OnClick specifies a function to be called when the menu item is clicked.
@@ -61,14 +78,34 @@ func (this *MenuItem) OnClick (callback func ()) event.Cookie {
 	return this.on.click.Connect(callback)
 }
 
-func (this *MenuItem) handleKeyUp (key input.Key, numberPad bool) {
-	if key != input.KeyEnter && key != input.Key(' ') { return }
-	this.on.click.Broadcast()
+func (this *MenuItem) handleMouseEnter () {
+	this.SetFocused(true)
 }
 
-func (this *MenuItem) handleMouseUp (button input.Button) {
-	if button != input.ButtonLeft { return }
-	if this.MousePosition().In(this.Bounds()) {
+func (this *MenuItem) handleMouseLeave () {
+	this.SetFocused(false)
+}
+
+func (this *MenuItem) handleKeyDown (key input.Key, numberPad bool) bool {
+	if key != input.KeyEnter && key != input.Key(' ') { return false }
+	return true
+}
+
+func (this *MenuItem) handleKeyUp (key input.Key, numberPad bool) bool {
+	if key != input.KeyEnter && key != input.Key(' ') { return false }
+	this.on.click.Broadcast()
+	return true
+}
+
+func (this *MenuItem) handleButtonDown (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	return true
+}
+
+func (this *MenuItem) handleButtonUp (button input.Button) bool {
+	if button != input.ButtonLeft { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.on.click.Broadcast()
 	}
+	return true
 }

mimeicon.go

@@ -0,0 +1,53 @@
+package objects
+
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/data"
+import "git.tebibyte.media/tomo/tomo/canvas"
+
+var _ tomo.Object = new(MimeIcon)
+
+// MimeIcon displays an icon of a MIME type.
+type MimeIcon struct {
+	box  tomo.Box
+	mime data.Mime
+	size tomo.IconSize
+}
+
+// NewMimeIcon creates a new icon from a MIME type.
+func NewMimeIcon (mime data.Mime, size tomo.IconSize) *MimeIcon {
+	mimeIcon := &MimeIcon {
+		box: tomo.NewBox(),
+	}
+	mimeIcon.box.SetRole(tomo.R("objects", "MimeIcon"))
+	mimeIcon.SetIcon(mime, size)
+	mimeIcon.box.OnIconSetChange(mimeIcon.handleIconSetChange)
+	return mimeIcon
+}
+
+// GetBox returns the underlying box.
+func (this *MimeIcon) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetIcon sets the MIME type and size of the icon.
+func (this *MimeIcon) SetIcon (mime data.Mime, size tomo.IconSize) {
+	if this.mime == mime && this.size == size { return }
+	this.mime = mime
+	this.size = size
+	this.setTexture(tomo.MimeIconTexture(mime, size))
+}
+
+func (this *MimeIcon) handleIconSetChange () {
+	this.setTexture(tomo.MimeIconTexture(this.mime, this.size))
+}
+
+func (this *MimeIcon) setTexture (texture canvas.Texture) {
+	this.box.SetAttr(tomo.ATexture(texture))
+	this.box.SetAttr(tomo.ATextureMode(tomo.TextureModeCenter))
+	if texture == nil {
+		this.box.SetAttr(tomo.AMinimumSize(0, 0))
+	} else {
+		bounds := texture.Bounds()
+		this.box.SetAttr(tomo.AttrMinimumSize(bounds.Max.Sub(bounds.Min)))
+	}
+}

numberinput.go

@@ -3,98 +3,133 @@ package objects
 import "math"
 import "strconv"
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/text"
 import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/objects/layouts"
 
+var _ tomo.Object = new(NumberInput)
+
 // NumberInput is an editable text box which accepts only numbers, and has
 // controls to increment and decrement its value.
 type NumberInput struct {
-	tomo.ContainerBox
+	box       tomo.ContainerBox
 	input     *TextInput
 	increment *Button
 	decrement *Button
 	on struct {
-		enter event.FuncBroadcaster
-		edit  event.FuncBroadcaster
+		valueChange event.FuncBroadcaster
+		confirm     event.FuncBroadcaster
 	}
 }
 
 // NewNumberInput creates a new number input with the specified value.
 func NewNumberInput (value float64) *NumberInput {
-	box := &NumberInput {
-		ContainerBox: tomo.NewContainerBox(),
-		input:        NewTextInput(""),
-		increment:    NewButton(""),
-		decrement:    NewButton(""),
+	numberInput := &NumberInput {
+		box:       tomo.NewContainerBox(),
+		input:     NewTextInput(""),
+		increment: NewButton(""),
+		decrement: NewButton(""),
 	}
-	box.SetRole(tomo.R("objects", "NumberInput", ""))
-	tomo.Apply(box)
-	box.Add(box.input)
-	box.Add(box.decrement)
-	box.Add(box.increment)
-	box.SetLayout(layouts.NewGrid([]bool { true, false, false }, []bool { true }))
-	box.increment.SetIcon(tomo.IconValueIncrement)
-	box.decrement.SetIcon(tomo.IconValueDecrement)
+	numberInput.box.SetRole(tomo.R("objects", "NumberInput"))
+	numberInput.box.Add(numberInput.input)
+	numberInput.box.Add(numberInput.decrement)
+	numberInput.box.Add(numberInput.increment)
+	numberInput.box.SetAttr(tomo.ALayout(layouts.Row { true, false, false }))
+	numberInput.increment.SetIcon(tomo.IconValueIncrement)
+	numberInput.decrement.SetIcon(tomo.IconValueDecrement)
 	
-	box.SetValue(value)
+	numberInput.SetValue(value)
 	
-	box.CaptureScroll(true)
-	box.CaptureKeyboard(true)
-	
-	box.OnScroll(box.handleScroll)
-	box.OnKeyDown(box.handleKeyDown)
-	box.input.OnEnter(box.handleEnter)
-	box.input.OnEdit(box.on.edit.Broadcast)
-	box.increment.OnClick(func () { box.shift(1)  })
-	box.decrement.OnClick(func () { box.shift(-1) })
-	return box
+	numberInput.box.OnScroll(numberInput.handleScroll)
+	numberInput.box.OnKeyDown(numberInput.handleKeyDown)
+	numberInput.box.OnKeyUp(numberInput.handleKeyUp)
+	numberInput.input.OnConfirm(numberInput.handleConfirm)
+	numberInput.input.OnValueChange(numberInput.on.valueChange.Broadcast)
+	numberInput.increment.OnClick(func () { numberInput.shift( 1) })
+	numberInput.decrement.OnClick(func () { numberInput.shift(-1) })
+	return numberInput
 }
 
-// SetValue sets the value of the input.
-func (this *NumberInput) SetValue (value float64) {
-	this.input.SetText(strconv.FormatFloat(value, 'g', -1, 64))
+// GetBox returns the underlying box.
+func (this *NumberInput) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this number input has keyboard focus. If set
+// to true, this method will steal focus away from whichever object currently
+// has focus.
+func (this *NumberInput) SetFocused (focused bool) {
+	this.input.SetFocused(focused)
+}
+
+// Select sets the text cursor or selection.
+func (this *NumberInput) Select (dot text.Dot) {
+	this.input.Select(dot)
+}
+
+// Dot returns the text cursor or selection.
+func (this *NumberInput) Dot () text.Dot {
+	return this.input.Dot()
 }
 
 // Value returns the value of the input.
 func (this *NumberInput) Value () float64 {
-	value, _ := strconv.ParseFloat(this.input.Text(), 64)
+	value, _ := strconv.ParseFloat(this.input.Value(), 64)
 	return value
 }
 
-// OnEnter specifies a function to be called when the user presses enter within
-// the text input.
-func (this *NumberInput) OnEnter (callback func ()) event.Cookie {
-	return this.on.enter.Connect(callback)
+// SetValue sets the value of the input.
+func (this *NumberInput) SetValue (value float64) {
+	this.input.SetValue(strconv.FormatFloat(value, 'g', -1, 64))
 }
 
-// OnEdit specifies a function to be called when the user edits the input value.
-func (this *NumberInput) OnEdit (callback func ()) event.Cookie {
-	return this.on.edit.Connect(callback)
+// OnValueChange specifies a function to be called when the user edits the input
+// value.
+func (this *NumberInput) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
+}
+
+// OnConfirm specifies a function to be called when the user presses enter within
+// the number input.
+func (this *NumberInput) OnConfirm (callback func ()) event.Cookie {
+	return this.on.confirm.Connect(callback)
 }
 
 func (this *NumberInput) shift (by int) {
 	this.SetValue(this.Value() + float64(by))
-	this.on.edit.Broadcast()
+	this.on.valueChange.Broadcast()
 }
 
-func (this *NumberInput) handleKeyDown (key input.Key, numpad bool) {
+func (this *NumberInput) handleKeyDown (key input.Key, numpad bool) bool {
 	switch key {
-	case input.KeyUp:   this.shift(1)
-	case input.KeyDown: this.shift(-1)
-	default:            this.input.handleKeyDown(key, numpad)
+	case input.KeyUp:
+		this.shift(1)
+		return true
+	case input.KeyDown:
+		this.shift(-1)
+		return true
 	}
+	return false
 }
 
-func (this *NumberInput) handleScroll (x, y float64) {
+func (this *NumberInput) handleKeyUp (key input.Key, numpad bool) bool {
+	switch key {
+	case input.KeyUp:   return true
+	case input.KeyDown: return true
+	}
+	return false
+}
+
+func (this *NumberInput) handleScroll (x, y float64) bool {
 	if x == 0 {
 		this.shift(-int(math.Round(y)))
-	} else {
-		this.input.handleScroll(x, y)
+		return true
 	}
+	return false
 }
 
-func (this *NumberInput) handleEnter () {
+func (this *NumberInput) handleConfirm () {
 	this.SetValue(this.Value())
-	this.on.enter.Broadcast()
+	this.on.confirm.Broadcast()
 }

scrollbar.go

@@ -5,11 +5,24 @@ import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 
+var _ tomo.Object = new(Scrollbar)
+
 // Scrollbar is a special type of slider that can control the scroll of any
-// overflowing ContainerBox.
+// overflowing ContainerObject.
+//
+// Sub-components:
+//   - ScrollbarHandle is the grabbable handle of the scrollbar.
+//
+// Tags:
+//   - [vertical] The scrollbar is oriented vertically.
+//   - [horizontall] The scrollbar is oriented horizontally.
+//
+// ScrollbarHandle tags:
+//   - [vertical] The handle is oriented vertically.
+//   - [horizontall] The handle is oriented horizontally.
 type Scrollbar struct {
-	tomo.ContainerBox
-	handle     *SliderHandle
+	box        tomo.ContainerBox
+	handle     *sliderHandle
 	layout     scrollbarLayout
 	dragging   bool
 	dragOffset image.Point
@@ -23,8 +36,8 @@ type Scrollbar struct {
 
 func newScrollbar (orient string) *Scrollbar {
 	this := &Scrollbar {
-		ContainerBox: tomo.NewContainerBox(),
-		handle: &SliderHandle {
+		box: tomo.NewContainerBox(),
+		handle: &sliderHandle {
 			Box: tomo.NewBox(),
 		},
 		layout: scrollbarLayout {
@@ -32,24 +45,21 @@ func newScrollbar (orient string) *Scrollbar {
 		},
 	}
 
-	this.Add(this.handle)
-	this.SetFocusable(true)
+	this.box.Add(this.handle)
 
-	this.CaptureDND(true)
-	this.CaptureMouse(true)
-	this.CaptureScroll(true)
-	this.CaptureKeyboard(true)
-
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnMouseDown(this.handleMouseDown)
-	this.OnMouseUp(this.handleMouseUp)
-	this.OnMouseMove(this.handleMouseMove)
-	this.OnScroll(this.handleScroll)
+	this.box.SetFocusable(true)
+	this.box.SetInputMask(true)
+	this.box.OnKeyUp(this.handleKeyUp)
+	this.box.OnKeyDown(this.handleKeyDown)
+	this.box.OnButtonDown(this.handleButtonDown)
+	this.box.OnButtonUp(this.handleButtonUp)
+	this.box.OnMouseMove(this.handleMouseMove)
+	this.box.OnScroll(this.handleScroll)
 	
-	this.handle.SetRole(tomo.R("objects", "SliderHandle", orient))
-	tomo.Apply(this.handle)
-	this.SetRole(tomo.R("objects", "Slider", orient))
-	tomo.Apply(this)
+	this.handle.SetRole(tomo.R("objects", "ScrollbarHandle"))
+	this.handle.SetTag(orient, true)
+	this.box.SetRole(tomo.R("objects", "Scrollbar"))
+	this.box.SetTag(orient, true)
 	return this
 }
 
@@ -63,13 +73,18 @@ func NewHorizontalScrollbar () *Scrollbar {
 	return newScrollbar("horizontal")
 }
 
+// GetBox returns the underlying box.
+func (this *Scrollbar) GetBox () tomo.Box {
+	return this.box
+}
+
 // Link assigns this scrollbar to a ContentObject. Closing the returned cookie
 // will unlink it.
 func (this *Scrollbar) Link (box tomo.ContentObject) event.Cookie {
 	this.layout.linked = box
 	this.linkCookie = this.newLinkCookie (
 		box.OnContentBoundsChange(this.handleLinkedContentBoundsChange))
-	this.SetLayout(this.layout)
+	this.box.SetAttr(tomo.ALayout(this.layout))
 	return this.linkCookie
 }
 
@@ -82,12 +97,20 @@ func (this *Scrollbar) handleLinkedContentBoundsChange () {
 	} else {
 		this.layout.value = this.layout.contentPos() / trackLength
 	}
-	this.SetLayout(this.layout)
+	this.box.SetAttr(tomo.ALayout(this.layout))
 	if this.layout.value != previousValue {
 		this.on.valueChange.Broadcast()
 	}
 }
 
+// Value returns the value of the scrollbar between 0 and 1 where 0 is scrolled
+// all the way to the left/top, and 1 is scrolled all the way to the
+// right/bottom.
+func (this *Scrollbar) Value () float64 {
+	if this.layout.linked == nil { return 0 }
+	return this.layout.value
+}
+
 // SetValue sets the value of the scrollbar between 0 and 1, where 0 is scrolled
 // all the way to the left/top, and 1 is scrolled all the way to the
 // right/bottom.
@@ -108,49 +131,77 @@ func (this *Scrollbar) SetValue (value float64) {
 	
 }
 
-// Value returns the value of the scrollbar between 0 and 1 where 0 is scrolled
-// all the way to the left/top, and 1 is scrolled all the way to the
-// right/bottom.
-func (this *Scrollbar) Value () float64 {
-	if this.layout.linked == nil { return 0 }
-	return this.layout.value
-}
-
-// OnValueChange specifies a function to be called when the position of the
-// scrollbar changes.
+// OnValueChange specifies a function to be called when the user changes the
+// position of the scrollbar.
 func (this *Scrollbar) OnValueChange (callback func ()) event.Cookie {
 	return this.on.valueChange.Connect(callback)
 }
 
-func (this *Scrollbar) handleKeyDown (key input.Key, numpad bool) {
-	var increment float64; if this.layout.vertical {
-		increment = -0.05
+// PageSize returns the scroll distance of a page.
+func (this *Scrollbar) PageSize () int {
+	if this.layout.linked == nil { return 0 }
+	viewport := this.layout.linked.GetBox().InnerBounds()
+	if this.layout.vertical {
+		return viewport.Dy()
 	} else {
-		increment = 0.05
-	}
-
-	switch key {
-	case input.KeyUp, input.KeyLeft:
-		if this.Modifiers().Alt {
-			this.SetValue(0)
-		} else {
-			this.SetValue(this.Value() - increment)
-		}
-	case input.KeyDown, input.KeyRight:
-		if this.Modifiers().Alt {
-			this.SetValue(1)
-		} else {
-			this.SetValue(this.Value() + increment)
-		}
-	case input.KeyHome:
-		this.SetValue(0)
-	case input.KeyEnd:
-		this.SetValue(1)
+		return viewport.Dx()
 	}
 }
 
-func (this *Scrollbar) handleMouseDown (button input.Button) {
-	pointer := this.MousePosition()
+// StepSize returns the scroll distance of a step.
+func (this *Scrollbar) StepSize () int {
+	// FIXME: this should not be hardcoded, need to get base font metrics
+	// from tomo somehow. should be (emspace, lineheight)
+	return 16
+}
+
+func (this *Scrollbar) handleKeyUp (key input.Key, numpad bool) bool {
+	switch key {
+	case input.KeyUp,   input.KeyLeft:  return true
+	case input.KeyDown, input.KeyRight: return true
+	case input.KeyPageUp:   return true
+	case input.KeyPageDown: return true
+	case input.KeyHome:     return true
+	case input.KeyEnd:      return true
+	}
+	return false
+}
+
+func (this *Scrollbar) handleKeyDown (key input.Key, numpad bool) bool {
+	modifiers := this.box.Window().Modifiers()
+
+	switch key {
+	case input.KeyUp, input.KeyLeft:
+		if modifiers.Alt {
+			this.SetValue(0)
+		} else {
+			this.scrollBy(this.StepSize())
+		}
+		return true
+	case input.KeyDown, input.KeyRight:
+		if modifiers.Alt {
+			this.SetValue(1)
+		} else {
+			this.scrollBy(-this.StepSize())
+		}
+	case input.KeyPageUp:
+		this.scrollBy(this.PageSize())
+		return true
+	case input.KeyPageDown:
+		this.scrollBy(-this.PageSize())
+		return true
+	case input.KeyHome:
+		this.SetValue(0)
+		return true
+	case input.KeyEnd:
+		this.SetValue(1)
+		return true
+	}
+	return false
+}
+
+func (this *Scrollbar) handleButtonDown (button input.Button) bool {
+	pointer := this.box.Window().MousePosition()
 	handle  := this.handle.Bounds()
 
 	within := pointer.In(handle)
@@ -166,7 +217,7 @@ func (this *Scrollbar) handleMouseDown (button input.Button) {
 			this.dragging   = true
 			this.dragOffset =
 				pointer.Sub(this.handle.Bounds().Min).
-				Add(this.InnerBounds().Min)
+				Add(this.box.InnerBounds().Min)
 			this.drag()
 		} else {
 			this.dragOffset = this.fallbackDragOffset()
@@ -175,39 +226,53 @@ func (this *Scrollbar) handleMouseDown (button input.Button) {
 		}
 	case input.ButtonMiddle:
 		if above {
-			this.scrollBy(this.pageSize())
+			this.scrollBy(this.PageSize())
 		} else {
-			this.scrollBy(-this.pageSize())
+			this.scrollBy(-this.PageSize())
 		}
 	case input.ButtonRight:
 		if above {
-			this.scrollBy(this.stepSize())
+			this.scrollBy(this.StepSize())
 		} else {
-			this.scrollBy(-this.stepSize())
+			this.scrollBy(-this.StepSize())
 		}
 	}
+	return true
 }
 
-func (this *Scrollbar) handleMouseUp (button input.Button) {
-	if button != input.ButtonLeft || !this.dragging { return }
+func (this *Scrollbar) handleButtonUp (button input.Button) bool {
+	if button != input.ButtonLeft || !this.dragging { return true }
 	this.dragging = false
+	return true
 }
 
-func (this *Scrollbar) handleMouseMove () {
-	if !this.dragging { return }
+func (this *Scrollbar) handleMouseMove () bool {
+	if !this.dragging { return false }
 	this.drag()
+	return true
 }
 
-func (this *Scrollbar) handleScroll (x, y float64) {
-	if this.layout.linked == nil { return }
+func (this *Scrollbar) handleScroll (x, y float64) bool {
+	if this.layout.linked == nil { return false }
+	
+	delta := (x + y)
+	if this.layout.vertical {
+		x = 0
+		y = delta
+	} else {
+		x = delta
+		y = 0
+	}
+	
 	this.layout.linked.ScrollTo (
 		this.layout.linked.ContentBounds().Min.
 		Sub(image.Pt(int(x), int(y))))
+	return true
 }
 
 func (this *Scrollbar) drag () {
-	pointer := this.MousePosition().Sub(this.dragOffset)
-	gutter  := this.InnerBounds()
+	pointer := this.box.Window().MousePosition().Sub(this.dragOffset)
+	gutter  := this.box.InnerBounds()
 	handle  := this.handle.Bounds()
 
 	if this.layout.vertical {
@@ -223,30 +288,14 @@ func (this *Scrollbar) drag () {
 
 func (this *Scrollbar) fallbackDragOffset () image.Point {
 	if this.layout.vertical {
-		return this.InnerBounds().Min.
+		return this.box.InnerBounds().Min.
 			Add(image.Pt(0, this.handle.Bounds().Dy() / 2))
 	} else {
-		return this.InnerBounds().Min.
+		return this.box.InnerBounds().Min.
 			Add(image.Pt(this.handle.Bounds().Dx() / 2, 0))
 	}
 }
 
-func (this *Scrollbar) pageSize () int {
-	if this.layout.linked == nil { return 0 }
-	viewport := this.layout.linked.GetBox().InnerBounds()
-	if this.layout.vertical {
-		return viewport.Dy()
-	} else {
-		return viewport.Dx()
-	}
-}
-
-func (this *Scrollbar) stepSize () int {
-	// FIXME: this should not be hardcoded, need to get base font metrics
-	// from tomo.somehow. should be (emspace, lineheight)
-	return 16
-}
-
 func (this *Scrollbar) scrollBy (distance int) {
 	if this.layout.linked == nil { return }
 	var vector image.Point; if this.layout.vertical {
@@ -276,7 +325,7 @@ func (this *scrollbarCookie) Close () {
 		cookie.Close()
 	}
 	this.owner.layout.linked = nil
-	this.owner.SetLayout(this.owner.layout)
+	this.owner.box.SetAttr(tomo.ALayout(this.owner.layout))
 }
 
 type scrollbarLayout struct {
@@ -285,14 +334,14 @@ type scrollbarLayout struct {
 	linked   tomo.ContentObject
 }
 
-func (scrollbarLayout) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
-	if len(boxes) != 1 { return image.Pt(0, 0) }
-	return boxes[0].MinimumSize()
+func (scrollbarLayout) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
+	if boxes.Len() != 1 { return image.Pt(0, 0) }
+	return boxes.MinimumSize(0)
 }
 
-func (this scrollbarLayout) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
-	if len(boxes) != 1 { return }
-	handle := image.Rectangle { Max: boxes[0].MinimumSize() }
+func (this scrollbarLayout) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
+	if boxes.Len() != 1 { return }
+	handle := image.Rectangle { Max: boxes.MinimumSize(0) }
 	gutter := hints.Bounds
 
 	var gutterLength float64;
@@ -313,7 +362,7 @@ func (this scrollbarLayout) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
 		// and we shouldn't be adding and removing boxes, so this is
 		// really the only good way to hide things.
 		// TODO perhaps have a "Hidden" rectangle in the Tomo API?
-		boxes[0].SetBounds(image.Rect(-16, -16, 0, 0))
+		boxes.SetBounds(0, image.Rect(-32, -32, -16, -16))
 		return
 	}
 	if this.vertical {
@@ -333,10 +382,18 @@ func (this scrollbarLayout) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
 	handle = handle.Sub(handleOffset).Add(gutter.Min)
 	
 	// place handle
-	boxes[0].SetBounds(handle)
+	boxes.SetBounds(0, handle)
 	
 }
 
+func (this scrollbarLayout) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	return this.MinimumSize(hints, boxes).X
+}
+
+func (this scrollbarLayout) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	return this.MinimumSize(hints, boxes).Y
+}
+
 func (this scrollbarLayout) viewportContentRatio () float64 {
 	if this.linked == nil { return 0 }
 	return this.viewportLength() / this.contentLength()

scrollcontainer.go

@@ -2,7 +2,9 @@ package objects
 
 import "image"
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/layouts"
 
 // ScrollSide determines which Scrollbars are active in a ScrollContainer.
 type ScrollSide int; const (
@@ -35,44 +37,64 @@ func (sides ScrollSide) String () string {
 	}
 }
 
+var _ tomo.Object = new(ScrollContainer)
+
 // ScrollContainer couples a ContentBox with one or two Scrollbars.
 type ScrollContainer struct {
-	tomo.ContainerBox
-	layout *scrollContainerLayout
+	box tomo.ContainerBox
 
+	root       tomo.ContentObject
+	horizontal *Scrollbar
+	vertical   *Scrollbar
+	
 	horizontalCookie event.Cookie
 	verticalCookie   event.Cookie
+
+	on struct {
+		valueChange event.FuncBroadcaster
+	}
 }
 
 // NewScrollContainer creates a new scroll container.
 func NewScrollContainer (sides ScrollSide) *ScrollContainer {
-	this := &ScrollContainer {
-		ContainerBox: tomo.NewContainerBox(),
-		layout:       &scrollContainerLayout { },
+	scrollContainer := &ScrollContainer {
+		box: tomo.NewContainerBox(),
 	}
 	if sides.Vertical() {
-		this.layout.vertical = NewVerticalScrollbar()
-		this.Add(this.layout.vertical)
+		scrollContainer.vertical = NewVerticalScrollbar()
+		scrollContainer.vertical.OnValueChange(scrollContainer.handleValueChange)
+		scrollContainer.box.Add(scrollContainer.vertical)
 	}
 	if sides.Horizontal() {
-		this.layout.horizontal = NewHorizontalScrollbar()
-		this.Add(this.layout.horizontal)
+		scrollContainer.horizontal = NewHorizontalScrollbar()
+		scrollContainer.horizontal.OnValueChange(scrollContainer.handleValueChange)
+		scrollContainer.box.Add(scrollContainer.horizontal)
 	}
-	this.CaptureScroll(true)
-	this.OnScroll(this.handleScroll)
-	this.SetRole(tomo.R("objects", "ScrollContainer", sides.String()))
-	tomo.Apply(this)
-	this.SetLayout(this.layout)
-	return this
+	scrollContainer.box.OnScroll(scrollContainer.handleScroll)
+	scrollContainer.box.OnKeyDown(scrollContainer.handleKeyDown)
+	scrollContainer.box.OnKeyUp(scrollContainer.handleKeyUp)
+	scrollContainer.box.SetRole(tomo.R("objects", "ScrollContainer"))
+	scrollContainer.box.SetTag(sides.String(), true)
+	if sides == ScrollHorizontal {
+		scrollContainer.box.SetAttr(tomo.ALayout(layouts.NewGrid(true)(true, false)))
+	} else {
+		scrollContainer.box.SetAttr(tomo.ALayout(layouts.NewGrid(true, false)(true, false)))
+	}
+	return scrollContainer
+}
+
+// GetBox returns the underlying box.
+func (this *ScrollContainer) GetBox () tomo.Box {
+	return this.box
 }
 
 // SetRoot sets the root child of the ScrollContainer. There can only be one at
 // a time, and setting it will remove and unlink the current child if there is
 // one.
 func (this *ScrollContainer) SetRoot (root tomo.ContentObject) {
-	if this.layout.root != nil {
+	if this.root != nil {
 		// remove root and close cookies
-		this.Remove(this.layout.root)
+		this.box.Remove(this.root)
 		if this.horizontalCookie != nil {
 			this.horizontalCookie.Close()
 			this.horizontalCookie = nil
@@ -82,109 +104,143 @@ func (this *ScrollContainer) SetRoot (root tomo.ContentObject) {
 			this.verticalCookie = nil
 		}
 	}
-	this.layout.root = root
+	this.root = root
 	if root != nil {
 		// insert root at the beginning (for keynav)
 		switch {
-		case this.layout.vertical != nil:
-			this.Insert(root, this.layout.vertical)
-		case this.layout.horizontal != nil:
-			this.Insert(root, this.layout.horizontal)
+		case this.vertical != nil:
+			this.box.Insert(root, this.vertical)
+		case this.horizontal != nil:
+			this.box.Insert(root, this.horizontal)
 		default:
-			this.Add(root)
+			this.box.Add(root)
 		}
 		
 		// link root and remember cookies
-		if this.layout.horizontal != nil {
-			this.horizontalCookie = this.layout.horizontal.Link(root)
+		if this.horizontal != nil {
+			this.horizontalCookie = this.horizontal.Link(root)
 		}
-		if this.layout.vertical != nil {
-			this.verticalCookie =  this.layout.vertical.Link(root)
+		if this.vertical != nil {
+			this.verticalCookie =  this.vertical.Link(root)
 		}
 	}
 }
 
-// SetValue sets the horizontal and vertical scrollbar values where 0 is all the
-// way to the left/top, and 1 is all the way to the right/bottom.
-func (this *ScrollContainer) SetValue (x, y float64) {
-	if this.layout.horizontal != nil {
-		this.layout.horizontal.SetValue(x)
-	}
-	if this.layout.vertical != nil {
-		this.layout.vertical.SetValue(y)
-	}
-}
-
 // Value returns the horizontal and vertical scrollbar values where 0 is all the
 // way to the left/top, and 1 is all the way to the right/bottom.
 func (this *ScrollContainer) Value () (x, y float64) {
-	if this.layout.horizontal != nil {
-		x = this.layout.horizontal.Value()
+	if this.horizontal != nil {
+		x = this.horizontal.Value()
 	}
-	if this.layout.vertical != nil {
-		y = this.layout.vertical.Value()
+	if this.vertical != nil {
+		y = this.vertical.Value()
 	}
 	return x, y
 }
 
-func (this *ScrollContainer) handleScroll (x, y float64) {
-	if this.layout.root == nil { return }
-	this.layout.root.ScrollTo (
-		this.layout.root.ContentBounds().Min.
-		Sub(image.Pt(int(x), int(y))))
-}
-
-type scrollContainerLayout struct {
-	root       tomo.ContentObject
-	horizontal *Scrollbar
-	vertical   *Scrollbar
-}
-
-func (this *scrollContainerLayout) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
-	var minimum image.Point; if this.root != nil {
-		minimum = this.root.GetBox().MinimumSize()
-	}
+// SetValue sets the horizontal and vertical scrollbar values where 0 is all the
+// way to the left/top, and 1 is all the way to the right/bottom.
+func (this *ScrollContainer) SetValue (x, y float64) {
 	if this.horizontal != nil {
-		minimum.Y += this.horizontal.MinimumSize().Y
+		this.horizontal.SetValue(x)
 	}
 	if this.vertical != nil {
-		minimum.X += this.vertical.MinimumSize().X
-		minimum.Y = max(minimum.Y, this.vertical.MinimumSize().Y)
-	}
-	if this.horizontal != nil {
-		minimum.X = max(minimum.X, this.horizontal.MinimumSize().X)
-	}
-	return minimum
-}
-
-func (this *scrollContainerLayout) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
-	rootBounds := hints.Bounds
-	if this.horizontal != nil {
-		rootBounds.Max.Y -= this.horizontal.MinimumSize().Y
-	}
-	if this.vertical != nil {
-		rootBounds.Max.X -= this.vertical.MinimumSize().X
-	}
-	if this.root != nil {
-		this.root.GetBox().SetBounds(rootBounds)
-	}
-	if this.horizontal != nil {
-		this.horizontal.SetBounds(image.Rect (
-			hints.Bounds.Min.X,
-			rootBounds.Max.Y,
-			rootBounds.Max.X,
-			hints.Bounds.Max.Y))
-	}
-	if this.vertical != nil {
-		this.vertical.SetBounds(image.Rect (
-			rootBounds.Max.X,
-			hints.Bounds.Min.Y,
-			hints.Bounds.Max.X,
-			rootBounds.Max.Y))
+		this.vertical.SetValue(y)
 	}
 }
 
-func max (x, y int) int {
-	if x > y { return x }
-	return y
+// OnValueChange specifies a function to be called when the user changes the
+// position of the horizontal or vertical scrollbars.
+func (this *ScrollContainer) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
+}
+
+// PageSize returns the scroll distance of a page.
+func (this *ScrollContainer) PageSize () image.Point {
+	page := image.Point { }
+	if this.horizontal != nil {
+		page.X = this.horizontal.PageSize()
+	}
+	if this.vertical != nil {
+		page.Y = this.vertical.PageSize()
+	}
+	return page
+}
+
+// StepSize returns the scroll distance of a step.
+func (this *ScrollContainer) StepSize () image.Point {
+	page := image.Point { }
+	if this.horizontal != nil {
+		page.X = this.horizontal.StepSize()
+	}
+	if this.vertical != nil {
+		page.Y = this.vertical.StepSize()
+	}
+	return page
+}
+
+func (this *ScrollContainer) handleValueChange () {
+	this.on.valueChange.Broadcast()
+}
+
+func (this *ScrollContainer) scrollBy (vector image.Point) {
+	if this.root == nil               { return }
+	if vector    == (image.Point { }) { return }
+	this.root.ScrollTo (
+		this.root.ContentBounds().Min.
+		Sub(vector))
+}
+
+func (this *ScrollContainer) handleScroll (x, y float64) bool {
+	if this.root == nil { return false }
+	this.scrollBy(image.Pt(int(x), int(y)))
+	return true
+}
+
+func (this *ScrollContainer) handleKeyDown (key input.Key, numpad bool) bool {
+	modifiers := this.box.Window().Modifiers()
+	vector    := image.Point { }
+	switch key {
+	case input.KeyPageUp:
+		if modifiers.Shift {
+			vector.X -= this.PageSize().X
+		} else {
+			vector.Y -= this.PageSize().Y
+		}
+		this.scrollBy(vector)
+		return true
+	case input.KeyPageDown:
+		if modifiers.Shift {
+			vector.X += this.PageSize().X
+		} else {
+			vector.Y += this.PageSize().Y
+		}
+		this.scrollBy(vector)
+		return true
+	case input.KeyUp:
+		if modifiers.Shift {
+			vector.X -= this.StepSize().X
+		} else {
+			vector.Y -= this.StepSize().Y
+		}
+		this.scrollBy(vector)
+		return true
+	case input.KeyDown:
+		if modifiers.Shift {
+			vector.X += this.StepSize().X
+		} else {
+			vector.Y += this.StepSize().Y
+		}
+		this.scrollBy(vector)
+		return true
+	}
+	return false
+}
+
+func (this *ScrollContainer) handleKeyUp (key input.Key, numpad bool) bool {
+	switch key {
+	case input.KeyPageUp:   return true
+	case input.KeyPageDown: return true
+	}
+	return false
 }

separator.go

@@ -2,17 +2,23 @@ package objects
 
 import "git.tebibyte.media/tomo/tomo"
 
+var _ tomo.Object = new(Separator)
+
 // Separator is a line for visually separating elements.
 type Separator struct {
-	tomo.Box
+	box tomo.Box
 }
 
 // NewSeparator creates a new separator line.
 func NewSeparator () *Separator {
 	this := &Separator {
-		Box: tomo.NewBox(),
+		box: tomo.NewBox(),
 	}
-	this.SetRole(tomo.R("objects", "Separator", ""))
-	tomo.Apply(this)
+	this.box.SetRole(tomo.R("objects", "Separator"))
 	return this
 }
+
+// GetBox returns the underlying box.
+func (this *Separator) GetBox () tomo.Box {
+	return this.box
+}

slider.go

@@ -1,62 +1,73 @@
 package objects
 
+import "math"
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 
+var _ tomo.Object = new(Slider)
+
 // Slider is a control that selects a numeric value between 0 and 1.
+//
+// Sub-components:
+//   - SliderHandle is the grabbable handle of the slider.
+//
+// Tags:
+//   - [vertical] The slider is oriented vertically.
+//   - [horizontall] The slider is oriented horizontally.
+//
+// SliderHandle tags:
+//   - [vertical] The handle is oriented vertically.
+//   - [horizontall] The handle is oriented horizontally.
 type Slider struct {
-	tomo.ContainerBox
-	handle     *SliderHandle
+	box        tomo.ContainerBox
+	handle     *sliderHandle
 	layout     sliderLayout
 	dragging   bool
 	dragOffset image.Point
 	step       float64
 
 	on struct {
-		slide event.FuncBroadcaster
+		valueChange event.FuncBroadcaster
+		confirm     event.FuncBroadcaster
 	}
 }
 
-// SliderHandle is a simple object that serves as a handle for sliders and
-// scrollbars. It is completely inert.
-type SliderHandle struct {
+type sliderHandle struct {
 	tomo.Box
 }
 
 func newSlider (orient string, value float64) *Slider {
-	this := &Slider {
-		ContainerBox: tomo.NewContainerBox(),
-		handle: &SliderHandle {
+	slider := &Slider {
+		box: tomo.NewContainerBox(),
+		handle: &sliderHandle {
 			Box: tomo.NewBox(),
 		},
 		layout: sliderLayout {
 			vertical: orient == "vertical",
+			value:    math.NaN(),
 		},
 		step: 0.05,
 	}
 
-	this.Add(this.handle)
-	this.SetFocusable(true)
-
-	this.CaptureDND(true)
-	this.CaptureMouse(true)
-	this.CaptureScroll(true)
-	this.CaptureKeyboard(true)
-
-	this.SetValue(value)
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnMouseDown(this.handleMouseDown)
-	this.OnMouseUp(this.handleMouseUp)
-	this.OnMouseMove(this.handleMouseMove)
-	this.OnScroll(this.handleScroll)
+	slider.handle.SetRole(tomo.R("objects", "SliderHandle"))
+	slider.handle.SetTag(orient, true)
+	slider.box.SetRole(tomo.R("objects", "Slider"))
+	slider.box.SetTag(orient, true)
 	
-	this.handle.SetRole(tomo.R("objects", "SliderHandle", orient))
-	tomo.Apply(this.handle)
-	this.SetRole(tomo.R("objects", "Slider", orient))
-	tomo.Apply(this)
-	return this
+	slider.box.Add(slider.handle)
+	slider.box.SetFocusable(true)
+	slider.SetValue(value)
+
+	slider.box.SetInputMask(true)
+	slider.box.OnKeyUp(slider.handleKeyUp)
+	slider.box.OnKeyDown(slider.handleKeyDown)
+	slider.box.OnButtonDown(slider.handleButtonDown)
+	slider.box.OnButtonUp(slider.handleButtonUp)
+	slider.box.OnMouseMove(slider.handleMouseMove)
+	slider.box.OnScroll(slider.handleScroll)
+	return slider
 }
 
 // NewVerticalSlider creates a new vertical slider with the specified value.
@@ -69,13 +80,25 @@ func NewHorizontalSlider (value float64) *Slider {
 	return newSlider("horizontal", value)
 }
 
+// GetBox returns the underlying box.
+func (this *Slider) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this slider has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *Slider) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
 // SetValue sets the value of the slider between 0 and 1.
 func (this *Slider) SetValue (value float64) {
 	if value < 0 { value = 0 }
 	if value > 1 { value = 1 }
 	if value == this.layout.value { return }
 	this.layout.value = value
-	this.SetLayout(this.layout)
+	this.box.SetAttr(tomo.ALayout(this.layout))
 }
 
 // Value returns the value of the slider between 0 and 1.
@@ -85,11 +108,17 @@ func (this *Slider) Value () float64 {
 
 // OnValueChange specifies a function to be called when the user moves the
 // slider.
-func (this *Slider) OnSlide (callback func ()) event.Cookie {
-	return this.on.slide.Connect(callback)
+func (this *Slider) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
 }
 
-func (this *Slider) handleKeyDown (key input.Key, numpad bool) {
+// OnConfirm specifies a function to be called when the user stops moving the
+// slider.
+func (this *Slider) OnConfirm (callback func ()) event.Cookie {
+	return this.on.confirm.Connect(callback)
+}
+
+func (this *Slider) handleKeyDown (key input.Key, numpad bool) bool {
 	var increment float64; if this.layout.vertical {
 		increment = -0.05
 	} else {
@@ -98,30 +127,45 @@ func (this *Slider) handleKeyDown (key input.Key, numpad bool) {
 
 	switch key {
 	case input.KeyUp, input.KeyLeft:
-		if this.Modifiers().Alt {
+		if this.box.Window().Modifiers().Alt {
 			this.SetValue(0)
 		} else {
 			this.SetValue(this.Value() - increment)
 		}
-		this.on.slide.Broadcast()
+		this.on.valueChange.Broadcast()
+		return true
 	case input.KeyDown, input.KeyRight:
-		if this.Modifiers().Alt {
+		if this.box.Window().Modifiers().Alt {
 			this.SetValue(1)
 		} else {
 			this.SetValue(this.Value() + increment)
 		}
-		this.on.slide.Broadcast()
+		this.on.valueChange.Broadcast()
+		return true
 	case input.KeyHome:
 		this.SetValue(0)
-		this.on.slide.Broadcast()
+		this.on.valueChange.Broadcast()
+		return true
 	case input.KeyEnd:
 		this.SetValue(1)
-		this.on.slide.Broadcast()
+		this.on.valueChange.Broadcast()
+		return true
 	}
+	return false
 }
 
-func (this *Slider) handleMouseDown (button input.Button) {
-	pointer := this.MousePosition()
+func (this *Slider) handleKeyUp (key input.Key, numpad bool) bool {
+	switch key {
+	case input.KeyUp,   input.KeyLeft:  return true
+	case input.KeyDown, input.KeyRight: return true
+	case input.KeyHome: return true
+	case input.KeyEnd:  return true
+	}
+	return false
+}
+
+func (this *Slider) handleButtonDown (button input.Button) bool {
+	pointer := this.box.Window().MousePosition()
 	handle  := this.handle.Bounds()
 	
 	within := pointer.In(handle)
@@ -137,7 +181,7 @@ func (this *Slider) handleMouseDown (button input.Button) {
 			this.dragging   = true
 			this.dragOffset =
 				pointer.Sub(this.handle.Bounds().Min).
-				Add(this.InnerBounds().Min)
+				Add(this.box.InnerBounds().Min)
 			this.drag()
 		} else {
 			this.dragOffset = this.fallbackDragOffset()
@@ -147,41 +191,51 @@ func (this *Slider) handleMouseDown (button input.Button) {
 	case input.ButtonMiddle:
 		if above {
 			this.SetValue(0)
-			this.on.slide.Broadcast()
+			this.on.valueChange.Broadcast()
+			this.on.confirm.Broadcast()
 		} else {
 			this.SetValue(1)
-			this.on.slide.Broadcast()
+			this.on.valueChange.Broadcast()
+			this.on.confirm.Broadcast()
 		}
 	case input.ButtonRight:
 		if above {
 			this.SetValue(this.Value() - this.step)
-			this.on.slide.Broadcast()
+			this.on.valueChange.Broadcast()
+			this.on.confirm.Broadcast()
 		} else {
 			this.SetValue(this.Value() + this.step)
-			this.on.slide.Broadcast()
+			this.on.valueChange.Broadcast()
+			this.on.confirm.Broadcast()
 		}
 	}
+	return true
 }
 
-func (this *Slider) handleMouseUp (button input.Button) {
-	if button != input.ButtonLeft || !this.dragging { return }
+func (this *Slider) handleButtonUp (button input.Button) bool {
+	if button != input.ButtonLeft || !this.dragging { return true }
 	this.dragging = false
+	this.on.confirm.Broadcast()
+	return true
 }
 
-func (this *Slider) handleMouseMove () {
-	if !this.dragging { return }
+func (this *Slider) handleMouseMove () bool {
+	if !this.dragging { return false }
 	this.drag()
+	return true
 }
 
-func (this *Slider) handleScroll (x, y float64) {
+func (this *Slider) handleScroll (x, y float64) bool {
 	delta := (x + y) * 0.005
 	this.SetValue(this.Value() + delta)
-	this.on.slide.Broadcast()
+	this.on.valueChange.Broadcast()
+	this.on.confirm.Broadcast()
+	return true
 }
 
 func (this *Slider) drag () {
-	pointer := this.MousePosition().Sub(this.dragOffset)
-	gutter  := this.InnerBounds()
+	pointer := this.box.Window().MousePosition().Sub(this.dragOffset)
+	gutter  := this.box.InnerBounds()
 	handle  := this.handle.Bounds()
 
 	if this.layout.vertical {
@@ -194,15 +248,15 @@ func (this *Slider) drag () {
 			float64(pointer.X) /
 			float64(gutter.Dx() - handle.Dx()))
 	}
-	this.on.slide.Broadcast()
+	this.on.valueChange.Broadcast()
 }
 
 func (this *Slider) fallbackDragOffset () image.Point {
 	if this.layout.vertical {
-		return this.InnerBounds().Min.
+		return this.box.InnerBounds().Min.
 			Add(image.Pt(0, this.handle.Bounds().Dy() / 2))
 	} else {
-		return this.InnerBounds().Min.
+		return this.box.InnerBounds().Min.
 			Add(image.Pt(this.handle.Bounds().Dx() / 2, 0))
 	}
 }
@@ -212,31 +266,37 @@ type sliderLayout struct {
 	value    float64
 }
 
-func (sliderLayout) MinimumSize (hints tomo.LayoutHints, boxes []tomo.Box) image.Point {
-	if len(boxes) != 1 { return image.Pt(0, 0) }
-	return boxes[0].MinimumSize()
+func (sliderLayout) MinimumSize (hints tomo.LayoutHints, boxes tomo.BoxQuerier) image.Point {
+	if boxes.Len() != 1 { return image.Pt(0, 0) }
+	return boxes.MinimumSize(0)
 }
 
-func (this sliderLayout) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
-	if len(boxes) != 1 { return }
-	handle := image.Rectangle { Max: boxes[0].MinimumSize() }
+func (this sliderLayout) Arrange (hints tomo.LayoutHints, boxes tomo.BoxArranger) {
+	if boxes.Len() != 1 { return }
+	handle := image.Rectangle { Max: boxes.MinimumSize(0) }
 	gutter := hints.Bounds
 
 	if this.vertical {
 		height := gutter.Dy() - handle.Dy()
 		offset := int(float64(height) * (1 - this.value))
 		handle.Max.X = gutter.Dx()
-		boxes[0].SetBounds (
-			handle.
-			Add(image.Pt(0, offset)).
-			Add(gutter.Min))
+		boxes.SetBounds (
+			0,
+			handle.Add(image.Pt(0, offset)).Add(gutter.Min))
 	} else {
 		width  := gutter.Dx() - handle.Dx()
 		offset := int(float64(width) * this.value)
 		handle.Max.Y = gutter.Dy()
-		boxes[0].SetBounds (
-			handle.
-			Add(image.Pt(offset, 0)).
-			Add(gutter.Min))
+		boxes.SetBounds (
+			0,
+			handle.Add(image.Pt(offset, 0)).Add(gutter.Min))
 	}
 }
+
+func (this sliderLayout) RecommendedHeight (hints tomo.LayoutHints, boxes tomo.BoxQuerier, width int) int {
+	return this.MinimumSize(hints, boxes).X
+}
+
+func (this sliderLayout) RecommendedWidth (hints tomo.LayoutHints, boxes tomo.BoxQuerier, height int) int {
+	return this.MinimumSize(hints, boxes).Y
+}

swatch.go

@@ -0,0 +1,209 @@
+package objects
+
+import "log"
+import "image"
+import "image/color"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/objects/layouts"
+import icolor "git.tebibyte.media/tomo/objects/internal/color"
+
+var _ tomo.Object = new(Swatch)
+
+// Swatch displays a color, allowing the user to edit it by clicking on it.
+type Swatch struct {
+	box     tomo.CanvasBox
+	value   color.Color
+	editing bool
+	label   string
+	on struct {
+		valueChange event.FuncBroadcaster
+		confirm     event.FuncBroadcaster
+	}
+}
+
+// NewSwatch creates a new swatch with the given color.
+func NewSwatch (value color.Color) *Swatch {
+	swatch := &Swatch {
+		box: tomo.NewCanvasBox(),
+	}
+	swatch.box.SetRole(tomo.R("objects", "Swatch"))
+	swatch.box.SetDrawer(swatch)
+	swatch.SetValue(value)
+	
+	swatch.box.OnButtonDown(swatch.handleButtonDown)
+	swatch.box.OnButtonUp(swatch.handleButtonUp)
+	swatch.box.OnKeyDown(swatch.handleKeyDown)
+	swatch.box.OnKeyUp(swatch.handleKeyUp)
+	swatch.box.SetFocusable(true)
+	return swatch
+}
+
+// GetBox returns the underlying box.
+func (this *Swatch) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this swatch has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *Swatch) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// Value returns the color of the swatch.
+func (this *Swatch) Value () color.Color {
+	return this.value
+}
+
+// SetValue sets the color of the swatch.
+func (this *Swatch) SetValue (value color.Color) {
+	this.value = value
+	if value == nil { value = color.Transparent }
+	this.box.Invalidate()
+}
+
+// OnValueChange specifies a function to be called when the swatch's color
+// is changed by the user.
+func (this *Swatch) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
+}
+
+// RGBA satisfies the color.Color interface
+func (this *Swatch) RGBA () (r, g, b, a uint32) {
+	if this.value == nil { return }
+	return this.value.RGBA()
+}
+
+// OnConfirm specifies a function to be called when the user selects "OK" in the
+// color picker.
+func (this *Swatch) OnConfirm (callback func ()) event.Cookie {
+	return this.on.confirm.Connect(callback)
+}
+
+// Choose creates a modal that allows the user to edit the color of the swatch.
+func (this *Swatch) Choose () {
+	if this.editing { return }
+
+	var err    error
+	var window tomo.Window
+	if parent := this.box.Window(); parent != nil {
+		window, err = parent.NewChild(image.Rectangle { })
+	} else {
+		window, err = tomo.NewWindow(image.Rectangle { })
+	}
+	if err != nil {
+		log.Println("objects: could not create swatch modal:", err)
+		return
+	}
+	if this.label == "" {
+		window.SetTitle("Select Color")
+	} else {
+		window.SetTitle(this.label)
+	}
+	
+	committed := false
+	
+	colorPicker  := NewHSVAColorPicker(this.Value())
+	colorMemory  := this.value
+	hexInput     := NewTextInput("")
+	hexInput.SetFocused(true)
+	cancelButton := NewButton("Cancel")
+	cancelButton.SetIcon(tomo.IconDialogCancel)
+	okButton     := NewButton("OK")
+	okButton.SetIcon(tomo.IconDialogOkay)
+	
+	updateHexInput := func () {
+		nrgba := color.NRGBAModel.Convert(colorPicker.Value()).(color.NRGBA)
+		hexInput.SetValue(icolor.FormatNRGBA(nrgba))
+	}
+	updateHexInput()
+	commit := func () {
+		committed = true
+		window.Close()
+	}
+	colorPicker.OnValueChange(func () {
+		this.userSetValue(colorPicker.Value())
+		updateHexInput()
+	})
+	hexInput.OnConfirm(commit)
+	hexInput.OnValueChange(func () {
+		nrgba := icolor.ParseNRGBA(hexInput.Value())
+		this.userSetValue(nrgba)
+		colorPicker.SetValue(nrgba)
+	})
+	cancelButton.OnClick(func () {
+		window.Close()
+	})
+	okButton.OnClick(commit)
+	
+	controlRow := NewInnerContainer (
+		layouts.ContractHorizontal,
+		cancelButton,
+		okButton)
+	controlRow.SetAlign(tomo.AlignEnd, tomo.AlignMiddle)
+	window.SetRoot(NewOuterContainer (
+		layouts.Column { true, false },
+		colorPicker,
+		NewInnerContainer(layouts.Row { false, true },
+			NewLabel("Hex"),
+			hexInput),
+		controlRow))
+	window.OnClose(func () {
+		if committed {
+			this.on.confirm.Broadcast()
+		} else {
+			this.userSetValue(colorMemory)
+		}
+		this.editing = false
+	})
+	this.editing = true
+	window.SetVisible(true)
+}
+
+func (this *Swatch) Draw (can canvas.Canvas) {
+	pen := can.Pen()
+	
+	// transparency slash
+	pen.Stroke(color.RGBA { R: 255, A: 255 })
+	pen.StrokeWeight(1)
+	pen.Path(this.box.Bounds().Min, this.box.Bounds().Max)
+	
+	// color
+	if this.value != nil {
+		pen.StrokeWeight(0)
+		pen.Fill(this.value)
+		pen.Rectangle(this.box.Bounds())
+	}
+}
+
+func (this *Swatch) userSetValue (value color.Color) {
+	this.SetValue(value)
+	this.on.valueChange.Broadcast()
+}
+
+func (this *Swatch) handleKeyDown (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
+	this.Choose()
+	return true
+}
+
+func (this *Swatch) handleKeyUp (key input.Key, numberPad bool) bool {
+	if !isClickingKey(key) { return false }
+	return true
+}
+
+func (this *Swatch) handleButtonDown (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	return true
+}
+
+func (this *Swatch) handleButtonUp (button input.Button) bool {
+	if !isClickingButton(button) { return false }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
+		this.Choose()
+	}
+	return true
+}

tabbedcontainer.go

@@ -0,0 +1,162 @@
+package objects
+
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+var _ tomo.Object = new(TabbedContainer)
+
+// TabbedContainer holds multiple objects, each in their own tab. The user can
+// click the tab bar at the top to choose which one is activated.
+//
+// Sub-components:
+//   - TabRow sits at the top of the container and contains a row of tabs.
+//   - TabSpacer sits at either end of the tab row, bookending the list of tabs.
+//   - Tab appears in the tab row for each tab in the container. The user can
+//     click on the tab to switch to it.
+//
+// TabSpacer tags:
+//   - [left] The spacer is on the left.
+//   - [right] The spacer is on the right.
+//
+// Tab tags:
+//   - [active] The tab is currently active and its contents are visible.
+type TabbedContainer struct {
+	box tomo.ContainerBox
+	
+	leftSpacer  tomo.Box
+	rightSpacer tomo.Box
+	tabsRow tomo.ContainerBox
+	active string
+	tabs []*tab
+}
+
+// NewTabbedContainer creates a new tabbed container.
+func NewTabbedContainer () *TabbedContainer {
+	tabbedContainer := &TabbedContainer {
+		box: tomo.NewContainerBox(),
+	}
+	tabbedContainer.box.SetRole(tomo.R("objects", "TabbedContainer"))
+	tabbedContainer.box.SetAttr(tomo.ALayout(layouts.Column { false, true }))
+	
+	tabbedContainer.tabsRow = tomo.NewContainerBox()
+	tabbedContainer.tabsRow.SetRole(tomo.R("objects", "TabRow"))
+	tabbedContainer.box.Add(tabbedContainer.tabsRow)
+	
+	tabbedContainer.leftSpacer = tomo.NewBox()
+	tabbedContainer.leftSpacer.SetRole(tomo.R("objects", "TabSpacer"))
+	tabbedContainer.leftSpacer.SetTag("left", true)
+	tabbedContainer.rightSpacer = tomo.NewBox()
+	tabbedContainer.rightSpacer.SetRole(tomo.R("objects", "TabSpacer"))
+	tabbedContainer.rightSpacer.SetTag("right", true)
+	
+	tabbedContainer.ClearTabs()
+	tabbedContainer.setTabRowLayout()
+	return tabbedContainer
+}
+
+// GetBox returns the underlying box.
+func (this *TabbedContainer) GetBox () tomo.Box {
+	return this.box
+}
+
+// Activate switches to a named tab.
+func (this *TabbedContainer) Activate (name string) {
+	if _, tab := this.findTab(this.active); tab != nil {
+		tab.setActive(false)
+		this.box.Remove(tab.root)
+	}
+	if _, tab := this.findTab(name); tab != nil {
+		tab.setActive(true)
+		this.box.Add(tab.root)
+	} else {
+		name = ""
+	}
+	this.active = name
+}
+
+// AddTab adds an object as a tab with the specified name.
+func (this *TabbedContainer) AddTab (name string, root tomo.Object) {
+	tab := &tab {
+		TextBox: tomo.NewTextBox(),
+		name:    name,
+		root:    root,
+	}
+	tab.SetRole(tomo.R("objects", "Tab"))
+	tab.SetText(name)
+	tab.OnButtonDown(func (button input.Button) bool {
+		if button != input.ButtonLeft { return false }
+		this.Activate(name)
+		return true
+	})
+	tab.OnButtonUp(func (button input.Button) bool {
+		if button != input.ButtonLeft { return false }
+		return true
+	})
+	
+	this.tabs = append(this.tabs, tab)
+	this.tabsRow.Insert(tab, this.rightSpacer)
+	this.setTabRowLayout()
+	
+	// if the row was empty before, activate this tab
+	if len(this.tabs) == 1 {
+		this.Activate(name)	
+	}
+}
+
+// RemoveTab removes the named tab.
+func (this *TabbedContainer) RemoveTab (name string) {
+	index, tab := this.findTab(name)
+	if index < 0 { return }
+	nextIndex := index - 1
+	
+	this.tabsRow.Remove(tab)
+	this.tabs = append(this.tabs[:index], this.tabs[index - 1:]...)
+	this.setTabRowLayout()
+	
+	if nextIndex < 0               { nextIndex = 0 }
+	if nextIndex >= len(this.tabs) { nextIndex = len(this.tabs) - 1 }
+	if nextIndex < 0 {
+		this.Activate("")
+	} else {
+		this.Activate(this.tabs[nextIndex].name)
+	}
+}
+
+// ClearTabs removes all tabs.
+func (this *TabbedContainer) ClearTabs () {
+	this.tabs = nil
+	this.tabsRow.Clear()
+	this.tabsRow.Add(this.leftSpacer)
+	this.tabsRow.Add(this.rightSpacer)
+}
+
+func (this *TabbedContainer) setTabRowLayout () {
+	row := make(layouts.Row, 1 + len(this.tabs) + 1)
+	row[len(row) - 1] = true
+	this.tabsRow.SetAttr(tomo.ALayout(row))
+}
+
+func (this *TabbedContainer) findTab (name string) (int, *tab) {
+	for index, tab := range this.tabs {
+		if tab.name == name { return index, tab }
+	}
+	return -1, nil
+}
+
+type tab struct {
+	tomo.TextBox
+	name string
+	root tomo.Object
+}
+
+func (this *tab) setActive (active bool) {
+	if active {
+		this.SetRole(tomo.R("objects", "Tab"))
+		this.SetTag("active", true)
+	} else {
+		this.SetRole(tomo.R("objects", "Tab"))
+		this.SetTag("active", false)
+	}
+}
+

textinput.go

@@ -1,118 +1,303 @@
 package objects
 
+import "time"
 import "image"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/text"
 import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/objects/internal/history"
+
+const textInputHistoryMaximum = 64
+const textInputHistoryMaxAge  = time.Second / 4
+var _ tomo.ContentObject = new(TextInput)
+
+type textHistoryItem struct {
+	text string
+	dot  text.Dot
+}
 
 // TextInput is a single-line editable text box.
 type TextInput struct {
-	tomo.TextBox
-	text []rune
+	box       tomo.TextBox
+	text      []rune
+	multiline bool
+	history   *history.History[textHistoryItem]
 	on struct {
-		enter event.FuncBroadcaster
-		edit  event.FuncBroadcaster
+		dotChange   event.FuncBroadcaster
+		valueChange event.FuncBroadcaster
+		confirm     event.FuncBroadcaster
 	}
 }
 
+func newTextInput (text string, multiline bool) *TextInput {
+	textInput := &TextInput {
+		box:       tomo.NewTextBox(),
+		text:      []rune(text),
+		multiline: multiline,
+		history:   history.NewHistory[textHistoryItem] (
+			textHistoryItem { text: text },
+			textInputHistoryMaximum),
+	}
+	textInput.box.SetRole(tomo.R("objects", "TextInput"))
+	textInput.box.SetTag("multiline", multiline)
+	if multiline {
+		textInput.box.SetAttr(tomo.AOverflow(false, true))
+		textInput.box.SetAttr(tomo.AWrap(true))
+		textInput.box.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignStart))
+	} else {
+		textInput.box.SetAttr(tomo.AOverflow(true, false))
+		textInput.box.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
+	}
+	textInput.box.SetText(text)
+	textInput.box.SetFocusable(true)
+	textInput.box.SetSelectable(true)
+	textInput.box.OnKeyDown(textInput.handleKeyDown)
+	textInput.box.OnKeyUp(textInput.handleKeyUp)
+	textInput.box.OnScroll(textInput.handleScroll)
+	textInput.box.OnDotChange(textInput.handleDotChange)
+	return textInput	
+}
+
 // NewTextInput creates a new text input containing the specified text.
 func NewTextInput (text string) *TextInput {
-	this := &TextInput { TextBox: tomo.NewTextBox() }
-	this.SetRole(tomo.R("objects", "TextInput", ""))
-	tomo.Apply(this)
-	this.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
-	this.SetText(text)
-	this.SetFocusable(true)
-	this.SetSelectable(true)
-	this.SetOverflow(true, false)
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnScroll(this.handleScroll)
-	return this
+	return newTextInput(text, false)
 }
 
-// SetText sets the text content of the input.
-func (this *TextInput) SetText (text string) {
+// NewMultilineTextInput creates a new multiline text input containing the
+// specified text.
+func NewMultilineTextInput (text string) *TextInput {
+	return newTextInput(text, true)
+}
+
+// GetBox returns the underlying box.
+func (this *TextInput) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this text input has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *TextInput) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// Select sets the text cursor or selection.
+func (this *TextInput) Select (dot text.Dot) {
+	this.box.Select(dot)
+	this.historySwapDot()
+}
+
+// Dot returns the text cursor or selection.
+func (this *TextInput) Dot () text.Dot {
+	return this.box.Dot()
+}
+
+// OnDotChange specifies a function to be called when the text cursor or
+// selection changes.
+func (this *TextInput) OnDotChange (callback func ()) event.Cookie {
+	return this.on.dotChange.Connect(callback)
+}
+
+// SetAlign sets the X and Y alignment of the text input.
+func (this *TextInput) SetAlign (x, y tomo.Align) {
+	this.box.SetAttr(tomo.AAlign(x, y))
+}
+
+// ContentBounds returns the bounds of the inner content of the text input
+// relative to the input's InnerBounds.
+func (this *TextInput) ContentBounds () image.Rectangle {
+	return this.box.ContentBounds()
+}
+
+// ScrollTo shifts the origin of the text input's content to the origin of the
+// inputs's InnerBounds, offset by the given point.
+func (this *TextInput) ScrollTo (position image.Point) {
+	this.box.ScrollTo(position)
+}
+
+// OnContentBoundsChange specifies a function to be called when the text input's
+// ContentBounds or InnerBounds changes.
+func (this *TextInput) OnContentBoundsChange (callback func ()) event.Cookie {
+	return this.box.OnContentBoundsChange(callback)
+}
+
+// SetValue sets the text content of the input.
+func (this *TextInput) SetValue (text string) {
 	this.text = []rune(text)
-	this.TextBox.SetText(text)
+	this.box.SetText(text)
+	this.logLargeAction()
 }
 
-// Text returns the text content of the input.
-func (this *TextInput) Text () string {
+// Value returns the text content of the input.
+func (this *TextInput) Value () string {
 	return string(this.text)
 }
 
-// OnEnter specifies a function to be called when the user presses enter within
-// the text input.
-func (this *TextInput) OnEnter (callback func ()) event.Cookie {
-	return this.on.enter.Connect(callback)
+// OnConfirm specifies a function to be called when the user presses enter
+// within the text input.
+func (this *TextInput) OnConfirm (callback func ()) event.Cookie {
+	return this.on.confirm.Connect(callback)
 }
 
-// OnEdit specifies a function to be called when the user edits the input text.
-func (this *TextInput) OnEdit (callback func ()) event.Cookie {
-	return this.on.edit.Connect(callback)
+// OnValueChange specifies a function to be called when the user edits the input
+// text.
+func (this *TextInput) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
 }
 
-func (this *TextInput) handleKeyDown (key input.Key, numpad bool) {
-	dot       := this.Dot()
-	modifiers := this.Modifiers()
-	word      := modifiers.Control
-	sel       := modifiers.Shift
-	changed   := false
+// Undo undoes the last action.
+func (this *TextInput) Undo () {
+	this.recoverHistoryItem(this.history.Undo())
+}
 
-	// TODO all dot control (movement, selection, etc) should be done in the
-	// backend. (editing should be done here, though)
-
-	switch {
-	case key == input.KeyEnter:
-		this.on.enter.Broadcast()
-	case key == input.KeyHome || (modifiers.Alt && key == input.KeyLeft):
-		dot.End = 0
-		if !sel { dot.Start = dot.End }
-	case key == input.KeyEnd || (modifiers.Alt && key == input.KeyRight):
-		dot.End = len(this.text)
-		if !sel { dot.Start = dot.End }
-	case key == input.KeyLeft:
-		if sel {
-			dot = text.SelectLeft(this.text, dot, word)
-		} else {
-			dot = text.MoveLeft(this.text, dot, word)
-		}
-	case key == input.KeyRight:
-		if sel {
-			dot = text.SelectRight(this.text, dot, word)
-		} else {
-			dot = text.MoveRight(this.text, dot, word)
-		}
-	case key == input.KeyBackspace:
-		this.text, dot = text.Backspace(this.text, dot, word)
-		changed = true
-	case key == input.KeyDelete:
-		this.text, dot = text.Delete(this.text, dot, word)
-		changed = true
-	case key == input.Key('a') && modifiers.Control:
-		dot.Start = 0
-		dot.End   = len(this.text)
-	case key.Printable():
-		this.text, dot = text.Type(this.text, dot, rune(key))
-		changed = true
-	}
-
-	this.Select(dot)
-	if changed {
-		this.SetText(string(this.text))
-		this.on.edit.Broadcast()
-	}
+// Redo redoes the last previously undone action.
+func (this *TextInput) Redo () {
+	this.recoverHistoryItem(this.history.Redo())
 }
 
 // Type types a character at the current dot position.
 func (this *TextInput) Type (char rune) {
 	dot := this.Dot()
+	this.historySwapDot()
 	this.text, dot = text.Type(this.text, dot, rune(char))
 	this.Select(dot)
-	this.SetText(string(this.text))
+	this.box.SetText(string(this.text))
+	this.logKeystroke()
 }
 
-func (this *TextInput) handleScroll (x, y float64) {
-	this.ScrollTo(this.ContentBounds().Min.Add(image.Pt(int(x), int(y))))
+func (this *TextInput) logKeystroke () {
+	if this.Dot().Empty() {
+		this.history.PushWeak (
+			this.currentHistoryState(),
+			textInputHistoryMaxAge)
+	} else {
+		this.logLargeAction()
+	}
+}
+
+func (this *TextInput) logLargeAction () {
+	this.history.Push(this.currentHistoryState())
+}
+
+func (this *TextInput) historySwapDot () {
+	top := this.history.Top()
+	top.dot = this.Dot()
+	this.history.SwapSilently(top)
+}
+
+func (this *TextInput) currentHistoryState () textHistoryItem {
+	return textHistoryItem {
+		text: string(this.text),
+		dot:  this.Dot(),
+	}
+}
+
+func (this *TextInput) recoverHistoryItem (item textHistoryItem) {
+	this.box.SetText(item.text)
+	this.text = []rune(item.text)
+	this.box.Select(item.dot)
+}
+
+// TODO: add things like alt+up/down to move lines
+
+func (this *TextInput) handleKeyDown (key input.Key, numpad bool) bool {
+	dot        := this.Dot()
+	txt        := this.text
+	modifiers  := this.box.Window().Modifiers()
+	word       := modifiers.Control
+	changed    := false
+
+	defer func () {
+		if changed {
+			this.historySwapDot()
+			this.text = txt
+			this.box.SetText(string(txt))
+			this.box.Select(dot)
+			this.on.valueChange.Broadcast()
+			this.on.dotChange.Broadcast()
+			this.logKeystroke()
+		}
+	} ()
+
+	typeRune := func () {
+		txt, dot = text.Type(txt, dot, rune(key))
+		changed = true
+	}
+
+	if this.multiline && !modifiers.Control {
+		switch {
+		case key == '\n', key == '\t':
+			typeRune()
+			return true
+		}
+	}
+
+	switch {
+	case isConfirmationKey(key):
+		this.on.confirm.Broadcast()
+		return true
+	case key == input.KeyBackspace:
+		txt, dot = text.Backspace(txt, dot, word)
+		changed = true
+		return true
+	case key == input.KeyDelete:
+		txt, dot = text.Delete(txt, dot, word)
+		changed = true
+		return true
+	case key.Printable() && !modifiers.Control:
+		typeRune()
+		return true
+	case key == 'z' || key == 'Z' && modifiers.Control:
+		if modifiers.Shift {
+			this.Redo()
+		} else {
+			this.Undo()
+		}
+		return true
+	case key == 'y' && modifiers.Control:
+		this.Redo()
+		return true
+	default:
+		return false
+	}
+}
+
+func (this *TextInput) handleKeyUp (key input.Key, numpad bool) bool {
+	modifiers := this.box.Window().Modifiers()
+
+	if this.multiline && !modifiers.Control {
+		switch {
+		case key == '\n', key == '\t':
+			return true
+		}
+	}
+	
+	switch {
+	case isConfirmationKey(key):
+		return true
+	case key == input.KeyBackspace:
+		return true
+	case key == input.KeyDelete:
+		return true
+	case key.Printable() && !modifiers.Control:
+		return true
+	case key == 'z' && modifiers.Control:
+		return true
+	case key == 'y' && modifiers.Control:
+		return true
+	default:
+		return false
+	}
+}
+
+func (this *TextInput) handleScroll (x, y float64) bool {
+	if x == 0 { return false }
+	this.ScrollTo(this.ContentBounds().Min.Sub(image.Pt(int(x), int(y))))
+	return true
+}
+
+func (this *TextInput) handleDotChange () {
+	this.historySwapDot()
+	this.on.dotChange.Broadcast()
 }

textview.go

@@ -2,26 +2,86 @@ package objects
 
 import "image"
 import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/text"
+import "git.tebibyte.media/tomo/tomo/event"
+
+var _ tomo.Object = new(TabbedContainer)
 
 // TextView is an area for displaying a large amount of multi-line text.
 type TextView struct {
-	tomo.TextBox
+	box tomo.TextBox
 }
 
 // NewTextView creates a new text view.
 func NewTextView (text string) *TextView {
-	this := &TextView { TextBox: tomo.NewTextBox() }
-	this.SetRole(tomo.R("objects", "TextView", ""))
-	tomo.Apply(this)
-	this.SetFocusable(true)
-	this.SetSelectable(true)
-	this.SetText(text)
-	this.SetOverflow(false, true)
-	this.SetWrap(true)
-	this.OnScroll(this.handleScroll)
-	return this
+	textView := &TextView { box: tomo.NewTextBox() }
+	textView.box.SetRole(tomo.R("objects", "TextView"))
+	textView.box.SetFocusable(true)
+	textView.box.SetSelectable(true)
+	textView.SetText(text)
+	textView.box.SetAttr(tomo.AOverflow(false, true))
+	textView.box.SetAttr(tomo.AWrap(true))
+	textView.box.OnScroll(textView.handleScroll)
+	return textView
 }
 
-func (this *TextView) handleScroll (x, y float64) {
-	this.ScrollTo(this.ContentBounds().Min.Add(image.Pt(int(x), int(y))))
+// GetBox returns the underlying box.
+func (this *TextView) GetBox () tomo.Box {
+	return this.box
+}
+
+// SetFocused sets whether or not this text view has keyboard focus. If set to
+// true, this method will steal focus away from whichever object currently has
+// focus.
+func (this *TextView) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
+}
+
+// Select sets the text cursor or selection.
+func (this *TextView) Select (dot text.Dot) {
+	this.box.Select(dot)
+}
+
+// Dot returns the text cursor or selection.
+func (this *TextView) Dot () text.Dot {
+	return this.box.Dot()
+}
+
+// OnDotChange specifies a function to be called when the text cursor or
+// selection changes.
+func (this *TextView) OnDotChange (callback func ()) event.Cookie {
+	return this.box.OnDotChange(callback)
+}
+
+// SetAlign sets the X and Y alignment of the text view.
+func (this *TextView) SetAlign (x, y tomo.Align) {
+	this.box.SetAttr(tomo.AAlign(x, y))
+}
+
+// ContentBounds returns the bounds of the inner content of the text view
+// relative to the text view's InnerBounds.
+func (this *TextView) ContentBounds () image.Rectangle {
+	return this.box.ContentBounds()
+}
+
+// ScrollTo shifts the origin of the text view's content to the origin of the
+// text view's InnerBounds, offset by the given point.
+func (this *TextView) ScrollTo (position image.Point) {
+	this.box.ScrollTo(position)
+}
+
+// OnContentBoundsChange specifies a function to be called when the text view's
+// ContentBounds or InnerBounds changes.
+func (this *TextView) OnContentBoundsChange (callback func ()) event.Cookie {
+	return this.box.OnContentBoundsChange(callback)
+}
+
+// SetText sets the text content of the view.
+func (this *TextView) SetText (text string) {
+	this.box.SetText(text)
+}
+
+func (this *TextView) handleScroll (x, y float64) bool {
+	this.ScrollTo(this.ContentBounds().Min.Sub(image.Pt(int(x), int(y))))
+	return true
 }