File. Why not.

Closes #9

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 _ 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
@@ -24,33 +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"))
-	box.label.SetAttr(tomo.AAlign(tomo.AlignMiddle, tomo.AlignMiddle))
-	box.SetAttr(tomo.ALayout(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.SetInputMask(true)
-	box.OnButtonDown(box.handleButtonDown)
-	box.OnButtonUp(box.handleButtonUp)
-	box.OnKeyDown(box.handleKeyDown)
-	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()
@@ -59,7 +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)
@@ -67,9 +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.SetTag("icon", this.icon != nil)
+	this.box.SetTag("icon", this.icon != nil)
 	this.applyLayout()
 }
 
@@ -80,11 +97,11 @@ func (this *Button) OnClick (callback func ()) event.Cookie {
 
 func (this *Button) applyLayout () {
 	if this.labelActive && this.icon == nil {
-		this.SetAttr(tomo.ALayout(buttonLayout))
+		this.box.SetAttr(tomo.ALayout(buttonLayout))
 	} else if !this.labelActive && this.icon != nil {
-		this.SetAttr(tomo.ALayout(iconButtonLayout))
+		this.box.SetAttr(tomo.ALayout(iconButtonLayout))
 	} else {
-		this.SetAttr(tomo.ALayout(bothButtonLayout))
+		this.box.SetAttr(tomo.ALayout(bothButtonLayout))
 	}
 }
 
@@ -106,7 +123,7 @@ func (this *Button) handleButtonDown (button input.Button) bool {
 
 func (this *Button) handleButtonUp (button input.Button) bool {
 	if !isClickingButton(button) { return false }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.on.click.Broadcast()
 	}
 	return true

calendar.go

@@ -6,10 +6,22 @@ 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 {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 	
 	grid tomo.ContainerBox
 	time time.Time
@@ -23,11 +35,11 @@ type Calendar struct {
 // NewCalendar creates a new calendar with the specified date.
 func NewCalendar (tm time.Time) *Calendar {
 	calendar := &Calendar {
-		ContainerBox: tomo.NewContainerBox(),
-		time:         tm,
+		box:  tomo.NewContainerBox(),
+		time: tm,
 	}
-	calendar.SetRole(tomo.R("objects", "Calendar"))
-	calendar.SetAttr(tomo.ALayout(layouts.ContractVertical))
+	calendar.box.SetRole(tomo.R("objects", "Calendar"))
+	calendar.box.SetAttr(tomo.ALayout(layouts.ContractVertical))
 	
 	prevButton := NewButton("")
 	prevButton.SetIcon(tomo.IconGoPrevious)
@@ -42,23 +54,28 @@ func NewCalendar (tm time.Time) *Calendar {
 		calendar.on.valueChange.Broadcast()
 	})
 	calendar.monthLabel = NewLabel("")
-	calendar.monthLabel.SetAttr(tomo.AAlign(tomo.AlignMiddle, tomo.AlignMiddle))
+	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.Add(NewInnerContainer (
+	calendar.box.Add(NewInnerContainer (
 		layouts.Row { false, true, false },
 		prevButton, calendar.monthLabel, nextButton))
-	calendar.Add(calendar.grid)
+	calendar.box.Add(calendar.grid)
 	
-	calendar.OnScroll(calendar.handleScroll)
+	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

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
@@ -15,18 +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"))
-	box.SetValue(value)
+	checkbox.box.SetRole(tomo.R("objects", "Checkbox"))
+	checkbox.SetValue(value)
 	
-	box.OnButtonDown(box.handleButtonDown)
-	box.OnButtonUp(box.handleButtonUp)
-	box.OnKeyDown(box.handleKeyDown)
-	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
+}
+
+// GetBox returns the underlying box.
+func (this *Checkbox) 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 *Checkbox) SetFocused (focused bool) {
+	this.box.SetFocused(focused)
 }
 
 // Value returns the value of the checkbox.
@@ -38,8 +56,8 @@ func (this *Checkbox) Value () bool {
 func (this *Checkbox) SetValue (value bool) {
 	this.value = value
 	// the theme shall decide what checked and unchecked states look like
-	this.SetTag("checked",    value)
-	this.SetTag("unchecked", !value)
+	this.box.SetTag("checked",    value)
+	this.box.SetTag("unchecked", !value)
 }
 
 // Toggle toggles the value of the checkbox between true and false.
@@ -71,7 +89,7 @@ func (this *Checkbox) handleButtonDown (button input.Button) bool {
 
 func (this *Checkbox) handleButtonUp (button input.Button) bool {
 	if !isClickingButton(button) { return false }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.Toggle()
 	}
 	return true

colorpicker.go

@@ -8,10 +8,16 @@ import "git.tebibyte.media/tomo/tomo/canvas"
 import "git.tebibyte.media/tomo/objects/layouts"
 import "git.tebibyte.media/tomo/objects/internal"
 
+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 {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 	value internal.HSVA
 	
 	pickerMap   *hsvaColorPickerMap
@@ -26,15 +32,15 @@ type HSVAColorPicker struct {
 // NewHSVAColorPicker creates a new color picker with the specified color.
 func NewHSVAColorPicker (value color.Color) *HSVAColorPicker {
 	picker := &HSVAColorPicker {
-		ContainerBox: tomo.NewContainerBox(),
+		box: tomo.NewContainerBox(),
 	}
-	picker.SetRole(tomo.R("objects", "ColorPicker"))
-	picker.SetAttr(tomo.ALayout(layouts.Row { true, false, false }))
+	picker.box.SetRole(tomo.R("objects", "ColorPicker"))
+	picker.box.SetAttr(tomo.ALayout(layouts.Row { true, false, false }))
 	picker.pickerMap = newHsvaColorPickerMap(picker)
-	picker.Add(picker.pickerMap)
+	picker.box.Add(picker.pickerMap)
 	
 	picker.hueSlider = NewVerticalSlider(0.0)
-	picker.Add(picker.hueSlider)
+	picker.box.Add(picker.hueSlider)
 	picker.hueSlider.OnValueChange(func () {
 		picker.value.H = picker.hueSlider.Value()
 		picker.on.valueChange.Broadcast()
@@ -42,7 +48,7 @@ func NewHSVAColorPicker (value color.Color) *HSVAColorPicker {
 	})
 	
 	picker.alphaSlider = NewVerticalSlider(0.0)
-	picker.Add(picker.alphaSlider)
+	picker.box.Add(picker.alphaSlider)
 	picker.alphaSlider.OnValueChange(func () {
 		picker.value.A = uint16(picker.alphaSlider.Value() * 0xFFFF)
 		picker.on.valueChange.Broadcast()
@@ -54,6 +60,18 @@ func NewHSVAColorPicker (value color.Color) *HSVAColorPicker {
 	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

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.SetAttr(tomo.ALayout(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"))
-	this.SetTag("outer", true)
+	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"))
-	this.SetTag("sunken", true)
+	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"))
-	this.SetTag("inner", true)
+	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 {
@@ -53,9 +53,10 @@ 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.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
+	messageText.SetAlign(tomo.AlignStart, tomo.AlignMiddle)
 
 	for _, option := range options {
 		if option, ok := option.(clickable); ok {
@@ -63,7 +64,7 @@ func NewDialog (kind DialogKind, parent tomo.Window, title, message string, opti
 		}
 	}
 	dialog.controlRow = NewInnerContainer(layouts.ContractHorizontal, options...)
-	dialog.controlRow.SetAttr(tomo.AAlign(tomo.AlignEnd, tomo.AlignEnd))
+	dialog.controlRow.SetAlign(tomo.AlignEnd, tomo.AlignEnd)
 
 	dialog.SetRoot(NewOuterContainer (
 		layouts.Column { true, false },

dropdown.go

@@ -6,10 +6,12 @@ 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 {
-	tomo.ContainerBox
+	box   tomo.ContainerBox
 	label *Label
 
 	value string
@@ -24,28 +26,40 @@ type Dropdown struct {
 // NewDropdown creates a new dropdown input with the specified items
 func NewDropdown (items ...string) *Dropdown {
 	dropdown := &Dropdown {
-		ContainerBox: tomo.NewContainerBox(),
+		box: tomo.NewContainerBox(),
 		label:        NewLabel(""),
 	}
-	dropdown.SetRole(tomo.R("objects", "Dropdown"))
-	dropdown.SetAttr(tomo.ALayout(layouts.Row { true, false }))
-	dropdown.Add(dropdown.label)
-	dropdown.Add(NewIcon(tomo.IconListChoose, tomo.IconSizeSmall))
+	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.SetInputMask(true)
-	dropdown.OnButtonDown(dropdown.handleButtonDown)
-	dropdown.OnButtonUp(dropdown.handleButtonUp)
-	dropdown.OnKeyDown(dropdown.handleKeyDown)
-	dropdown.OnKeyUp(dropdown.handleKeyUp)
-	dropdown.SetFocusable(true)
+	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 {
@@ -107,7 +121,7 @@ func (this *Dropdown) handleButtonDown (button input.Button) bool {
 
 func (this *Dropdown) handleButtonUp (button input.Button) bool {
 	if !isClickingButton(button) { return false }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	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
+}

heading.go

@@ -2,30 +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"))
-	this.SetTag(fmt.Sprint(level), true)
+	this := &Heading { box: tomo.NewTextBox() }
+	this.box.SetRole(tomo.R("objects", "Heading"))
+	this.box.SetTag(fmt.Sprint(level), true)
 	this.SetText(text)
-	this.SetSelectable(true)
-	this.SetFocusable(true)
+	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.SetTag("menu", true)
+	heading.box.SetTag("menu", true)
 	return heading
 }

icon.go

@@ -3,9 +3,16 @@ package objects
 import "git.tebibyte.media/tomo/tomo"
 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
 }
@@ -21,14 +28,19 @@ func iconSizeString (size tomo.IconSize) string {
 // NewIcon creates a new icon from an icon ID.
 func NewIcon (icon tomo.Icon, size tomo.IconSize) *Icon {
 	this := &Icon {
-		Box: tomo.NewBox(),
+		box: tomo.NewBox(),
 	}
-	this.SetRole(tomo.R("objects", "Icon"))
+	this.box.SetRole(tomo.R("objects", "Icon"))
 	this.SetIcon(icon, size)
-	this.OnIconSetChange(this.handleIconSetChange)
+	this.box.OnIconSetChange(this.handleIconSetChange)
 	return this
 }
 
+// GetBox returns the underlying box.
+func (this *Icon) GetBox () tomo.Box {
+	return this.box
+}
+
 // SetIcon sets the icon.
 func (this *Icon) SetIcon (icon tomo.Icon, size tomo.IconSize) {
 	if this.icon == icon { return }
@@ -42,12 +54,12 @@ func (this *Icon) handleIconSetChange () {
 }
 
 func (this *Icon) setTexture (texture canvas.Texture) {
-	this.SetAttr(tomo.ATexture(texture))
-	this.SetAttr(tomo.ATextureMode(tomo.TextureModeCenter))
+	this.box.SetAttr(tomo.ATexture(texture))
+	this.box.SetAttr(tomo.ATextureMode(tomo.TextureModeCenter))
 	if texture == nil {
-		this.SetAttr(tomo.AMinimumSize(0, 0))
+		this.box.SetAttr(tomo.AMinimumSize(0, 0))
 	} else {
 		bounds := texture.Bounds()
-		this.SetAttr(tomo.AttrMinimumSize(bounds.Max.Sub(bounds.Min)))
+		this.box.SetAttr(tomo.AttrMinimumSize(bounds.Max.Sub(bounds.Min)))
 	}
 }

label.go

@@ -1,19 +1,60 @@
 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"))
+	this := &Label { box: tomo.NewTextBox() }
+	this.box.SetRole(tomo.R("objects", "Label"))
 	this.SetText(text)
-	this.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
-	this.SetSelectable(true)
-	this.SetFocusable(true)
+	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))
+}

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
 }
@@ -15,22 +17,39 @@ 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"))
-	box.label.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
-	box.label.SetSelectable(false)
-	box.label.SetFocusable(false)
-	box.Add(box.checkbox)
-	box.Add(box.label)
-	box.SetAttr(tomo.ALayout(layouts.Row { false, true }))
+	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.OnButtonDown(box.handleButtonDown)
-	box.OnButtonUp(box.handleButtonUp)
-	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.
@@ -61,7 +80,7 @@ func (this *LabelCheckbox) handleButtonDown (button input.Button) bool {
 
 func (this *LabelCheckbox) handleButtonUp (button input.Button) bool {
 	if !isClickingButton(button) { return false }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.checkbox.SetFocused(true)
 		this.checkbox.Toggle()
 	}

labelswatch.go

@@ -6,31 +6,52 @@ 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 {
-	tomo.ContainerBox
-	swatch  *Swatch
-	label   *Label
+	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 {
-	box := &LabelSwatch {
-		ContainerBox: tomo.NewContainerBox(),
-		swatch:       NewSwatch(value),
-		label:        NewLabel(text),
+	labelSwatch := &LabelSwatch {
+		box:    tomo.NewContainerBox(),
+		swatch: NewSwatch(value),
+		label:  NewLabel(text),
 	}
-	box.SetRole(tomo.R("objects", "LabelSwatch"))
-	box.swatch.label = text
-	box.label.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
-	box.Add(box.swatch)
-	box.Add(box.label)
-	box.SetAttr(tomo.ALayout(layouts.Row { false, true }))
+	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 }))
 
-	box.OnButtonDown(box.handleButtonDown)
-	box.OnButtonUp(box.handleButtonUp)
-	return box
+	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.
@@ -61,13 +82,13 @@ func (this *LabelSwatch) OnConfirm (callback func ()) event.Cookie {
 }
 
 func (this *LabelSwatch) handleButtonDown (button input.Button) bool {
-	if button != input.ButtonLeft { return true }
+	if !isClickingButton(button) { return true }
 	return true
 }
 
 func (this *LabelSwatch) handleButtonUp (button input.Button) bool {
-	if button != input.ButtonLeft { return true }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	if !isClickingButton(button) { return true }
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.swatch.SetFocused(true)
 		this.swatch.Choose()
 	}

menu.go

@@ -7,6 +7,10 @@ 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
 
@@ -72,6 +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()
@@ -90,21 +95,27 @@ 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 key != input.KeyEnter && key != input.Key(' ') { return false }
+		if !isClickingKey(key) { return false }
 		return true
 	})
 	tearLine.OnKeyUp(func (key input.Key, numberPad bool) bool {
-		if key != input.KeyEnter && key != input.Key(' ') { return false }
+		if !isClickingKey(key) { return false }
 		this.TearOff()
 		return true
 	})
 	tearLine.OnButtonDown(func (button input.Button) bool {
-		if button != input.ButtonLeft { return false }
+		if !isClickingButton(button) { return false }
 		return true
 	})
 	tearLine.OnButtonUp(func (button input.Button) bool {
-		if button != input.ButtonLeft { return false }
+		if !isClickingButton(button) { return false }
 		if tearLine.Window().MousePosition().In(tearLine.Bounds()) {
 			this.TearOff()
 		}

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"
 
+var _ tomo.Object = new(MenuItem)
+
 // MenuItem is a selectable memu item.
 type MenuItem struct {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 
-	label *Label
-	icon  *Icon
+	label       *Label
+	icon        *Icon
 	labelActive bool
 	
 	on struct {
@@ -25,25 +27,39 @@ func NewMenuItem (text string) *MenuItem {
 
 // NewIconMenuItem creates a new menu item with the specified icon and text.
 func NewIconMenuItem (icon tomo.Icon, text string) *MenuItem {
-	box := &MenuItem {
-		ContainerBox: tomo.NewContainerBox(),
-		label:        NewLabel(text),
-		icon:         NewIcon(icon, tomo.IconSizeSmall),
+	menuItem := &MenuItem {
+		box:   tomo.NewContainerBox(),
+		label: NewLabel(text),
+		icon:  NewIcon(icon, tomo.IconSizeSmall),
 	}
-	box.SetRole(tomo.R("objects", "MenuItem"))
-	box.label.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
-	box.SetAttr(tomo.ALayout(layouts.Row { false, 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.SetInputMask(true)
-	box.OnButtonDown(box.handleButtonDown)
-	box.OnButtonUp(box.handleButtonUp)
-	box.OnKeyDown(box.handleKeyDown)
-	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.
@@ -62,6 +78,14 @@ func (this *MenuItem) OnClick (callback func ()) event.Cookie {
 	return this.on.click.Connect(callback)
 }
 
+func (this *MenuItem) handleMouseEnter () {
+	this.SetFocused(true)
+}
+
+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
@@ -80,7 +104,7 @@ func (this *MenuItem) handleButtonDown (button input.Button) bool {
 
 func (this *MenuItem) handleButtonUp (button input.Button) bool {
 	if button != input.ButtonLeft { return false }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.on.click.Broadcast()
 	}
 	return true

mimeicon.go

@@ -4,22 +4,29 @@ 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 {
-	tomo.Box
+	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 {
-	this := &MimeIcon {
-		Box: tomo.NewBox(),
+	mimeIcon := &MimeIcon {
+		box: tomo.NewBox(),
 	}
-	this.SetRole(tomo.R("objects", "MimeIcon"))
-	this.SetIcon(mime, size)
-	this.OnIconSetChange(this.handleIconSetChange)
-	return this
+	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.
@@ -35,12 +42,12 @@ func (this *MimeIcon) handleIconSetChange () {
 }
 
 func (this *MimeIcon) setTexture (texture canvas.Texture) {
-	this.SetAttr(tomo.ATexture(texture))
-	this.SetAttr(tomo.ATextureMode(tomo.TextureModeCenter))
+	this.box.SetAttr(tomo.ATexture(texture))
+	this.box.SetAttr(tomo.ATextureMode(tomo.TextureModeCenter))
 	if texture == nil {
-		this.SetAttr(tomo.AMinimumSize(0, 0))
+		this.box.SetAttr(tomo.AMinimumSize(0, 0))
 	} else {
 		bounds := texture.Bounds()
-		this.SetAttr(tomo.AttrMinimumSize(bounds.Max.Sub(bounds.Min)))
+		this.box.SetAttr(tomo.AttrMinimumSize(bounds.Max.Sub(bounds.Min)))
 	}
 }

numberinput.go

@@ -3,14 +3,17 @@ 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
@@ -22,41 +25,63 @@ type NumberInput struct {
 
 // 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"))
-	box.Add(box.input)
-	box.Add(box.decrement)
-	box.Add(box.increment)
-	box.SetAttr(tomo.ALayout(layouts.Row { true, false, false }))
-	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.OnScroll(box.handleScroll)
-	box.OnKeyDown(box.handleKeyDown)
-	box.OnKeyUp(box.handleKeyUp)
-	box.input.OnConfirm(box.handleConfirm)
-	box.input.OnValueChange(box.on.valueChange.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
+}
+
+// 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
 }
 
 // SetValue sets the value of the input.
 func (this *NumberInput) SetValue (value float64) {
-	this.input.SetText(strconv.FormatFloat(value, 'g', -1, 64))
+	this.input.SetValue(strconv.FormatFloat(value, 'g', -1, 64))
 }
 
 // OnValueChange specifies a function to be called when the user edits the input

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 {
@@ -32,21 +45,21 @@ func newScrollbar (orient string) *Scrollbar {
 		},
 	}
 
-	this.Add(this.handle)
+	this.box.Add(this.handle)
 
-	this.SetFocusable(true)
-	this.SetInputMask(true)
-	this.OnKeyUp(this.handleKeyUp)
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnButtonDown(this.handleButtonDown)
-	this.OnButtonUp(this.handleButtonUp)
-	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"))
+	this.handle.SetRole(tomo.R("objects", "ScrollbarHandle"))
 	this.handle.SetTag(orient, true)
-	this.SetRole(tomo.R("objects", "Slider"))
-	this.SetTag(orient, true)
+	this.box.SetRole(tomo.R("objects", "Scrollbar"))
+	this.box.SetTag(orient, true)
 	return this
 }
 
@@ -60,13 +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.SetAttr(tomo.ALayout(this.layout))
+	this.box.SetAttr(tomo.ALayout(this.layout))
 	return this.linkCookie
 }
 
@@ -79,7 +97,7 @@ func (this *Scrollbar) handleLinkedContentBoundsChange () {
 	} else {
 		this.layout.value = this.layout.contentPos() / trackLength
 	}
-	this.SetAttr(tomo.ALayout(this.layout))
+	this.box.SetAttr(tomo.ALayout(this.layout))
 	if this.layout.value != previousValue {
 		this.on.valueChange.Broadcast()
 	}
@@ -150,7 +168,7 @@ func (this *Scrollbar) handleKeyUp (key input.Key, numpad bool) bool {
 }
 
 func (this *Scrollbar) handleKeyDown (key input.Key, numpad bool) bool {
-	modifiers := this.Window().Modifiers()
+	modifiers := this.box.Window().Modifiers()
 
 	switch key {
 	case input.KeyUp, input.KeyLeft:
@@ -183,7 +201,7 @@ func (this *Scrollbar) handleKeyDown (key input.Key, numpad bool) bool {
 }
 
 func (this *Scrollbar) handleButtonDown (button input.Button) bool {
-	pointer := this.Window().MousePosition()
+	pointer := this.box.Window().MousePosition()
 	handle  := this.handle.Bounds()
 
 	within := pointer.In(handle)
@@ -199,7 +217,7 @@ func (this *Scrollbar) handleButtonDown (button input.Button) bool {
 			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()
@@ -253,8 +271,8 @@ func (this *Scrollbar) handleScroll (x, y float64) bool {
 }
 
 func (this *Scrollbar) drag () {
-	pointer := this.Window().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 {
@@ -270,10 +288,10 @@ 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))
 	}
 }
@@ -307,7 +325,7 @@ func (this *scrollbarCookie) Close () {
 		cookie.Close()
 	}
 	this.owner.layout.linked = nil
-	this.owner.SetAttr(tomo.ALayout(this.owner.layout))
+	this.owner.box.SetAttr(tomo.ALayout(this.owner.layout))
 }
 
 type scrollbarLayout struct {

scrollcontainer.go

@@ -37,9 +37,11 @@ func (sides ScrollSide) String () string {
 	}
 }
 
+var _ tomo.Object = new(ScrollContainer)
+
 // ScrollContainer couples a ContentBox with one or two Scrollbars.
 type ScrollContainer struct {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 
 	root       tomo.ContentObject
 	horizontal *Scrollbar
@@ -55,30 +57,35 @@ type ScrollContainer struct {
 
 // NewScrollContainer creates a new scroll container.
 func NewScrollContainer (sides ScrollSide) *ScrollContainer {
-	this := &ScrollContainer {
-		ContainerBox: tomo.NewContainerBox(),
+	scrollContainer := &ScrollContainer {
+		box: tomo.NewContainerBox(),
 	}
 	if sides.Vertical() {
-		this.vertical = NewVerticalScrollbar()
-		this.vertical.OnValueChange(this.handleValueChange)
-		this.Add(this.vertical)
+		scrollContainer.vertical = NewVerticalScrollbar()
+		scrollContainer.vertical.OnValueChange(scrollContainer.handleValueChange)
+		scrollContainer.box.Add(scrollContainer.vertical)
 	}
 	if sides.Horizontal() {
-		this.horizontal = NewHorizontalScrollbar()
-		this.horizontal.OnValueChange(this.handleValueChange)
-		this.Add(this.horizontal)
+		scrollContainer.horizontal = NewHorizontalScrollbar()
+		scrollContainer.horizontal.OnValueChange(scrollContainer.handleValueChange)
+		scrollContainer.box.Add(scrollContainer.horizontal)
 	}
-	this.OnScroll(this.handleScroll)
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnKeyUp(this.handleKeyUp)
-	this.SetRole(tomo.R("objects", "ScrollContainer"))
-	this.SetTag(sides.String(), true)
+	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 {
-		this.SetAttr(tomo.ALayout(layouts.NewGrid(true)(true, false)))
+		scrollContainer.box.SetAttr(tomo.ALayout(layouts.NewGrid(true)(true, false)))
 	} else {
-		this.SetAttr(tomo.ALayout(layouts.NewGrid(true, false)(true, false)))
+		scrollContainer.box.SetAttr(tomo.ALayout(layouts.NewGrid(true, false)(true, false)))
 	}
-	return this
+	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
@@ -87,7 +94,7 @@ func NewScrollContainer (sides ScrollSide) *ScrollContainer {
 func (this *ScrollContainer) SetRoot (root tomo.ContentObject) {
 	if this.root != nil {
 		// remove root and close cookies
-		this.Remove(this.root)
+		this.box.Remove(this.root)
 		if this.horizontalCookie != nil {
 			this.horizontalCookie.Close()
 			this.horizontalCookie = nil
@@ -102,11 +109,11 @@ func (this *ScrollContainer) SetRoot (root tomo.ContentObject) {
 		// insert root at the beginning (for keynav)
 		switch {
 		case this.vertical != nil:
-			this.Insert(root, this.vertical)
+			this.box.Insert(root, this.vertical)
 		case this.horizontal != nil:
-			this.Insert(root, this.horizontal)
+			this.box.Insert(root, this.horizontal)
 		default:
-			this.Add(root)
+			this.box.Add(root)
 		}
 		
 		// link root and remember cookies
@@ -191,7 +198,7 @@ func (this *ScrollContainer) handleScroll (x, y float64) bool {
 }
 
 func (this *ScrollContainer) handleKeyDown (key input.Key, numpad bool) bool {
-	modifiers := this.Window().Modifiers()
+	modifiers := this.box.Window().Modifiers()
 	vector    := image.Point { }
 	switch key {
 	case input.KeyPageUp:

separator.go

@@ -2,16 +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"))
+	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

@@ -6,10 +6,23 @@ 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
@@ -21,16 +34,14 @@ type Slider struct {
 	}
 }
 
-// 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 {
@@ -40,23 +51,23 @@ func newSlider (orient string, value float64) *Slider {
 		step: 0.05,
 	}
 
-	this.Add(this.handle)
-	this.SetFocusable(true)
-	this.SetValue(value)
+	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.SetInputMask(true)
-	this.OnKeyUp(this.handleKeyUp)
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnButtonDown(this.handleButtonDown)
-	this.OnButtonUp(this.handleButtonUp)
-	this.OnMouseMove(this.handleMouseMove)
-	this.OnScroll(this.handleScroll)
+	slider.box.Add(slider.handle)
+	slider.box.SetFocusable(true)
+	slider.SetValue(value)
 
-	this.handle.SetRole(tomo.R("objects", "SliderHandle"))
-	this.handle.SetTag(orient, true)
-	this.SetRole(tomo.R("objects", "Slider"))
-	this.SetTag(orient, true)
-	return this
+	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.SetAttr(tomo.ALayout(this.layout))
+	this.box.SetAttr(tomo.ALayout(this.layout))
 }
 
 // Value returns the value of the slider between 0 and 1.
@@ -104,7 +127,7 @@ func (this *Slider) handleKeyDown (key input.Key, numpad bool) bool {
 
 	switch key {
 	case input.KeyUp, input.KeyLeft:
-		if this.Window().Modifiers().Alt {
+		if this.box.Window().Modifiers().Alt {
 			this.SetValue(0)
 		} else {
 			this.SetValue(this.Value() - increment)
@@ -112,7 +135,7 @@ func (this *Slider) handleKeyDown (key input.Key, numpad bool) bool {
 		this.on.valueChange.Broadcast()
 		return true
 	case input.KeyDown, input.KeyRight:
-		if this.Window().Modifiers().Alt {
+		if this.box.Window().Modifiers().Alt {
 			this.SetValue(1)
 		} else {
 			this.SetValue(this.Value() + increment)
@@ -142,7 +165,7 @@ func (this *Slider) handleKeyUp (key input.Key, numpad bool) bool {
 }
 
 func (this *Slider) handleButtonDown (button input.Button) bool {
-	pointer := this.Window().MousePosition()
+	pointer := this.box.Window().MousePosition()
 	handle  := this.handle.Bounds()
 	
 	within := pointer.In(handle)
@@ -158,7 +181,7 @@ func (this *Slider) handleButtonDown (button input.Button) bool {
 			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()
@@ -211,8 +234,8 @@ func (this *Slider) handleScroll (x, y float64) bool {
 }
 
 func (this *Slider) drag () {
-	pointer := this.Window().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 {
@@ -230,10 +253,10 @@ func (this *Slider) drag () {
 
 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))
 	}
 }

swatch.go

@@ -10,12 +10,14 @@ import "git.tebibyte.media/tomo/tomo/canvas"
 import "git.tebibyte.media/tomo/objects/layouts"
 import "git.tebibyte.media/tomo/objects/internal"
 
+var _ tomo.Object = new(Swatch)
+
 // Swatch displays a color, allowing the user to edit it by clicking on it.
 type Swatch struct {
-	tomo.CanvasBox
-	value color.Color
+	box     tomo.CanvasBox
+	value   color.Color
 	editing bool
-	label string
+	label   string
 	on struct {
 		valueChange event.FuncBroadcaster
 		confirm     event.FuncBroadcaster
@@ -25,20 +27,32 @@ type Swatch struct {
 // NewSwatch creates a new swatch with the given color.
 func NewSwatch (value color.Color) *Swatch {
 	swatch := &Swatch {
-		CanvasBox: tomo.NewCanvasBox(),
+		box: tomo.NewCanvasBox(),
 	}
-	swatch.SetRole(tomo.R("objects", "Swatch"))
-	swatch.SetDrawer(swatch)
+	swatch.box.SetRole(tomo.R("objects", "Swatch"))
+	swatch.box.SetDrawer(swatch)
 	swatch.SetValue(value)
 	
-	swatch.OnButtonDown(swatch.handleButtonDown)
-	swatch.OnButtonUp(swatch.handleButtonUp)
-	swatch.OnKeyDown(swatch.handleKeyDown)
-	swatch.OnKeyUp(swatch.handleKeyUp)
-	swatch.SetFocusable(true)
+	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
@@ -48,7 +62,7 @@ func (this *Swatch) Value () color.Color {
 func (this *Swatch) SetValue (value color.Color) {
 	this.value = value
 	if value == nil { value = color.Transparent }
-	this.Invalidate()
+	this.box.Invalidate()
 }
 
 // OnValueChange specifies a function to be called when the swatch's color
@@ -75,7 +89,7 @@ func (this *Swatch) Choose () {
 
 	var err    error
 	var window tomo.Window
-	if parent := this.Window(); parent != nil {
+	if parent := this.box.Window(); parent != nil {
 		window, err = parent.NewChild(image.Rectangle { })
 	} else {
 		window, err = tomo.NewWindow(image.Rectangle { })
@@ -129,7 +143,7 @@ func (this *Swatch) Choose () {
 		layouts.ContractHorizontal,
 		cancelButton,
 		okButton)
-	controlRow.SetAttr(tomo.AAlign(tomo.AlignEnd, tomo.AlignMiddle))
+	controlRow.SetAlign(tomo.AlignEnd, tomo.AlignMiddle)
 	window.SetRoot(NewOuterContainer (
 		layouts.Column { true, false },
 		colorPicker,
@@ -155,13 +169,13 @@ func (this *Swatch) Draw (can canvas.Canvas) {
 	// transparency slash
 	pen.Stroke(color.RGBA { R: 255, A: 255 })
 	pen.StrokeWeight(1)
-	pen.Path(this.Bounds().Min, this.Bounds().Max)
+	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.Bounds())
+		pen.Rectangle(this.box.Bounds())
 	}
 }
 
@@ -188,7 +202,7 @@ func (this *Swatch) handleButtonDown (button input.Button) bool {
 
 func (this *Swatch) handleButtonUp (button input.Button) bool {
 	if !isClickingButton(button) { return false }
-	if this.Window().MousePosition().In(this.Bounds()) {
+	if this.box.Window().MousePosition().In(this.box.Bounds()) {
 		this.Choose()
 	}
 	return true

tabbedcontainer.go

@@ -4,8 +4,25 @@ 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 {
-	tomo.ContainerBox
+	box tomo.ContainerBox
 	
 	leftSpacer  tomo.Box
 	rightSpacer tomo.Box
@@ -14,43 +31,51 @@ type TabbedContainer struct {
 	tabs []*tab
 }
 
+// NewTabbedContainer creates a new tabbed container.
 func NewTabbedContainer () *TabbedContainer {
-	container := &TabbedContainer {
-		ContainerBox: tomo.NewContainerBox(),
+	tabbedContainer := &TabbedContainer {
+		box: tomo.NewContainerBox(),
 	}
-	container.SetRole(tomo.R("objects", "TabbedContainer"))
-	container.SetAttr(tomo.ALayout(layouts.Column { false, true }))
+	tabbedContainer.box.SetRole(tomo.R("objects", "TabbedContainer"))
+	tabbedContainer.box.SetAttr(tomo.ALayout(layouts.Column { false, true }))
 	
-	container.tabsRow = tomo.NewContainerBox()
-	container.tabsRow.SetRole(tomo.R("objects", "TabRow"))
-	container.Add(container.tabsRow)
+	tabbedContainer.tabsRow = tomo.NewContainerBox()
+	tabbedContainer.tabsRow.SetRole(tomo.R("objects", "TabRow"))
+	tabbedContainer.box.Add(tabbedContainer.tabsRow)
 	
-	container.leftSpacer = tomo.NewBox()
-	container.leftSpacer.SetRole(tomo.R("objects", "TabSpacer"))
-	container.leftSpacer.SetTag("left", true)
-	container.rightSpacer = tomo.NewBox()
-	container.rightSpacer.SetRole(tomo.R("objects", "TabSpacer"))
-	container.rightSpacer.SetTag("left", true)
+	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)
 	
-	container.ClearTabs()
-	container.setTabRowLayout()
-	return container
+	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.Remove(tab.root)
+		this.box.Remove(tab.root)
 	}
 	if _, tab := this.findTab(name); tab != nil {
 		tab.setActive(true)
-		this.Add(tab.root)
+		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(),
@@ -79,6 +104,7 @@ func (this *TabbedContainer) AddTab (name string, root tomo.Object) {
 	}
 }
 
+// RemoveTab removes the named tab.
 func (this *TabbedContainer) RemoveTab (name string) {
 	index, tab := this.findTab(name)
 	if index < 0 { return }
@@ -97,6 +123,7 @@ func (this *TabbedContainer) RemoveTab (name string) {
 	}
 }
 
+// ClearTabs removes all tabs.
 func (this *TabbedContainer) ClearTabs () {
 	this.tabs = nil
 	this.tabsRow.Clear()

textinput.go

@@ -6,35 +6,109 @@ import "git.tebibyte.media/tomo/tomo/text"
 import "git.tebibyte.media/tomo/tomo/input"
 import "git.tebibyte.media/tomo/tomo/event"
 
+var _ tomo.ContentObject = new(TextInput)
+
 // TextInput is a single-line editable text box.
 type TextInput struct {
-	tomo.TextBox
-	text []rune
+	box       tomo.TextBox
+	text      []rune
+	multiline bool
 	on struct {
 		valueChange event.FuncBroadcaster
 		confirm     event.FuncBroadcaster
 	}
 }
 
+func newTextInput (text string, multiline bool) *TextInput {
+	textInput := &TextInput {
+		box:       tomo.NewTextBox(),
+		multiline: multiline,
+	}
+	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.SetValue(text)
+	textInput.box.SetFocusable(true)
+	textInput.box.SetSelectable(true)
+	textInput.box.OnKeyDown(textInput.handleKeyDown)
+	textInput.box.OnKeyUp(textInput.handleKeyUp)
+	textInput.box.OnScroll(textInput.handleScroll)
+	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"))
-	this.SetAttr(tomo.AAlign(tomo.AlignStart, tomo.AlignMiddle))
-	this.SetAttr(tomo.AOverflow(true, false))
-	this.SetText(text)
-	this.SetFocusable(true)
-	this.SetSelectable(true)
-	this.OnKeyDown(this.handleKeyDown)
-	this.OnKeyUp(this.handleKeyUp)
-	this.OnScroll(this.handleScroll)
-	return this
+	return newTextInput(text, false)
+}
+
+// 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)
+}
+
+// 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.box.OnDotChange(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)
 }
 
 // Value returns the text content of the input.
@@ -42,16 +116,6 @@ func (this *TextInput) Value () string {
 	return string(this.text)
 }
 
-// SetText sets the text content of the input.
-func (this *TextInput) SetText (text string) {
-	this.SetValue(text)
-}
-
-// Text returns the text content of the input.
-func (this *TextInput) Text () string {
-	return this.Value()
-}
-
 // OnConfirm specifies a function to be called when the user presses enter
 // within the text input.
 func (this *TextInput) OnConfirm (callback func ()) event.Cookie {
@@ -69,23 +133,38 @@ func (this *TextInput) Type (char rune) {
 	dot := this.Dot()
 	this.text, dot = text.Type(this.text, dot, rune(char))
 	this.Select(dot)
-	this.SetText(string(this.text))
+	this.box.SetText(string(this.text))
 }
 
+// TODO: add up/down controls if this is a multiline input
+
 func (this *TextInput) handleKeyDown (key input.Key, numpad bool) bool {
 	dot       := this.Dot()
-	modifiers := this.Window().Modifiers()
+	modifiers := this.box.Window().Modifiers()
 	word      := modifiers.Control
 	changed   := false
 
 	defer func () {
 		this.Select(dot)
 		if changed {
-			this.SetText(string(this.text))
+			this.box.SetText(string(this.text))
 			this.on.valueChange.Broadcast()
 		}
 	} ()
 
+	typ := func () {
+		this.text, dot = text.Type(this.text, dot, rune(key))
+		changed = true
+	}
+
+	if this.multiline && !modifiers.Control {
+		switch {
+		case key == '\n', key == '\t':
+			typ()
+			return true
+		}
+	}
+
 	switch {
 	case isConfirmationKey(key):
 		this.on.confirm.Broadcast()
@@ -99,8 +178,7 @@ func (this *TextInput) handleKeyDown (key input.Key, numpad bool) bool {
 		changed = true
 		return true
 	case key.Printable() && !modifiers.Control:
-		this.text, dot = text.Type(this.text, dot, rune(key))
-		changed = true
+		typ()
 		return true
 	default:
 		return false
@@ -108,7 +186,15 @@ func (this *TextInput) handleKeyDown (key input.Key, numpad bool) bool {
 }
 
 func (this *TextInput) handleKeyUp (key input.Key, numpad bool) bool {
-	modifiers := this.Window().Modifiers()
+	modifiers := this.box.Window().Modifiers()
+
+	if this.multiline && !modifiers.Control {
+		switch {
+		case key == '\n', key == '\t':
+			return true
+		}
+	}
+	
 	switch {
 	case isConfirmationKey(key):
 		return true

textview.go

@@ -2,23 +2,83 @@ 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"))
-	this.SetFocusable(true)
-	this.SetSelectable(true)
-	this.SetText(text)
-	this.SetAttr(tomo.AOverflow(false, true))
-	this.SetAttr(tomo.AWrap(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
+}
+
+// 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 {