Add doc comments to the cut layout

layouts/cut.go

@@ -0,0 +1,212 @@
+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 [2]*Cut
+	expand   [2]bool
+	vertical bool
+}
+
+// Vertical divides the layout in equal halves vertically.
+func (this *Cut) Vertical () (top, bottom *Cut) {
+	this.fill()
+	this.even()
+	this.vertical = true
+	return this.Branches()
+}
+
+// Top divides the layout vertically, expanding the top half and contracting the
+// bottom half.
+func (this *Cut) Top () (top, bottom *Cut) {
+	this.fill()
+	this.first()
+	this.vertical = true
+	return this.Branches()
+}
+
+// Bottom divides the layout vertically, expanding the bottom half and
+// contracting the top half.
+func (this *Cut) Bottom () (top, bottom *Cut) {
+	this.fill()
+	this.second()
+	this.vertical = true
+	return this.Branches()
+}
+
+// Horizontal divides the layout in equal halves horizontally.
+func (this *Cut) Horizontal () (top, bottom *Cut) {
+	this.fill()
+	this.even()
+	return this.Branches()
+}
+
+// Left divides the layout horizontally, expanding the left half and contracting
+// the right half.
+func (this *Cut) Left () (top, bottom *Cut) {
+	this.fill()
+	this.first()
+	return this.Branches()
+}
+
+// Right divides the layout horizontally, expanding the right half and
+// contracting the left half.
+func (this *Cut) Right () (top, bottom *Cut) {
+	this.fill()
+	this.second()
+	return this.Branches()
+}
+
+// Branches returns the two halves of this layout.
+func (this *Cut) Branches () (first, second *Cut) {
+	return this.branches[0], this.branches[1]
+}
+
+func (this *Cut) real () bool {
+	return this != nil && this.branches[0] != nil && this.branches[1] != nil
+}
+
+func (this *Cut) fill () {
+	this.branches[0] = &Cut { }
+	this.branches[1] = &Cut { }
+}
+
+func (this *Cut) first () {
+	this.expand[0] = true
+	this.expand[1] = false
+}
+
+func (this *Cut) second () {
+	this.expand[0] = false
+	this.expand[1] = true
+}
+
+func (this *Cut) even () {
+	this.expand[0] = true
+	this.expand[1] = true
+}
+
+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 {
+	// collect minimum sizes and physical endpoints
+	var minimums [2]image.Point
+	var leaves   [2]tomo.Box
+	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 [2]image.Rectangle
+	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
+}

separator.go

@@ -4,11 +4,15 @@ import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/theme"
 
 // Separator is a line for visually separating elements.
-type Separator tomo.Box
+type Separator struct {
+	tomo.Box
+}
 
-// NewSeparator creates a new text label.
-func NewSeparator () Separator {
-	this := Separator(tomo.NewBox())
+// NewSeparator creates a new separator line.
+func NewSeparator () *Separator {
+	this := &Separator {
+		Box: tomo.NewBox(),
+	}
 	theme.Apply(this, theme.R("objects", "Separator", ""))
 	return this
 }

slider.go

@@ -1,38 +1,206 @@
 package objects
 
+import "image"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/theme"
+import "git.tebibyte.media/tomo/tomo/input"
+import "git.tebibyte.media/tomo/tomo/event"
 
+// UNDER CONSTRUCTION!
 
 type Slider struct {
 	tomo.ContainerBox
 	handle     *SliderHandle
-	vertical bool
+	layout     sliderLayout
+	dragging   bool
+	dragOffset image.Point
+	
+	on struct {
+		valueChange event.FuncBroadcaster
+	}
 }
 
 type SliderHandle struct {
 	tomo.Box
 }
 
-func newSlider (orient string) *Slider {
+func newSlider (orient string, value float64) *Slider {
 	this := &Slider {
 		ContainerBox: tomo.NewContainerBox(),
 		handle: &SliderHandle {
 			Box: tomo.NewBox(),
 		},
+		layout: sliderLayout {
 			vertical: orient == "vertical",
+		},
 	}
 	
 	this.Add(this.handle)
+	this.SetFocusable(true)
+	this.SetPropagateEvents(false)
+	this.SetValue(value)
+	this.OnKeyDown(this.handleKeyDown)
+	this.OnMouseDown(this.handleMouseDown)
+	this.OnMouseUp(this.handleMouseUp)
+	this.OnMouseMove(this.handleMouseMove)
 	theme.Apply(this.handle, theme.R("objects", "SliderHandle", orient))
 	theme.Apply(this,        theme.R("objects", "Slider", orient))
 	return this
 }
 
-func NewVerticalSlider () *Slider {
-	return newSlider("vertical")
+func NewVerticalSlider (value float64) *Slider {
+	return newSlider("vertical", value)
 }
 
-func NewHorizontalSlider () *Slider {
-	return newSlider("horizontal")
+func NewHorizontalSlider (value float64) *Slider {
+	return newSlider("horizontal", value)
+}
+
+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.on.valueChange.Broadcast()
+}
+
+func (this *Slider) Value () float64 {
+	return this.layout.value
+}
+
+func (this *Slider) OnValueChange (callback func ()) event.Cookie {
+	return this.on.valueChange.Connect(callback)
+}
+
+func (this *Slider) handleKeyDown (key input.Key, numpad bool) {
+	switch key {
+	case input.KeyUp, input.KeyLeft:
+		if this.Modifiers().Alt {
+			this.SetValue(0)
+		} else {
+			this.SetValue(this.Value() - 0.05)		
+		}
+	case input.KeyDown, input.KeyRight:
+		if this.Modifiers().Alt {
+			this.SetValue(1)
+		} else {
+			this.SetValue(this.Value() + 0.05)		
+		}
+	case input.KeyHome:
+		this.SetValue(0)
+	case input.KeyEnd:
+		this.SetValue(1)
+	}
+}
+
+func (this *Slider) handleMouseDown (button input.Button) {
+	pointer := this.MousePosition()
+	handle  := this.handle.Bounds()
+	var above, within bool
+	
+	if pointer.In(handle) {
+		within = true
+	} else if this.layout.vertical {
+		above = pointer.Y < handle.Min.Y
+	} else {
+		above = pointer.X < handle.Min.X
+	}
+	
+	switch button {
+	case input.ButtonLeft:
+		if within {
+			this.dragging   = true
+			this.dragOffset =
+				pointer.Sub(this.handle.Bounds().Min).
+				Add(this.InnerBounds().Min)
+			this.drag()
+		} else {
+			this.dragOffset = this.fallbackDragOffset()
+			this.dragging   = true
+			this.drag()
+		}
+	case input.ButtonMiddle:
+		if above {
+			this.SetValue(0)
+		} else {
+			this.SetValue(1)
+		}
+	case input.ButtonRight:
+		if above {
+			this.SetValue(this.Value() - 0.05)
+		} else {
+			this.SetValue(this.Value() + 0.05)
+		}
+	}
+}
+
+func (this *Slider) handleMouseUp (button input.Button) {
+	if button != input.ButtonLeft || !this.dragging { return }
+	this.dragging = false
+}
+
+func (this *Slider) handleMouseMove () {
+	if !this.dragging { return }
+	this.drag()
+}
+
+func (this *Slider) drag () {
+	pointer := this.MousePosition().Sub(this.dragOffset)
+	gutter  := this.InnerBounds()
+	handle  := this.handle.Bounds()
+
+	if this.layout.vertical {
+		this.SetValue (
+			float64(pointer.Y) /
+			float64(gutter.Dy() - handle.Dy()))
+	} else {
+		this.SetValue (
+			float64(pointer.X) /
+			float64(gutter.Dx() - handle.Dx()))
+	}
+}
+
+func (this *Slider) fallbackDragOffset () image.Point {
+	if this.layout.vertical {
+		return this.InnerBounds().Min.
+			Add(image.Pt(0, this.handle.Bounds().Dy() / 2))
+	} else {
+		return this.InnerBounds().Min.
+			Add(image.Pt(this.handle.Bounds().Dx() / 2, 0))
+	}
+}
+
+type sliderLayout struct {
+	vertical bool
+	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 (this sliderLayout) Arrange (hints tomo.LayoutHints, boxes []tomo.Box) {
+	if len(boxes) != 1 { return }
+	handle := image.Rectangle { Max: boxes[0].MinimumSize() }
+	gutter := hints.Bounds
+	
+	if this.vertical {
+		height := gutter.Dy() - handle.Dy()
+		offset := int(float64(height) * this.value)
+		gutter.Max.X = handle.Max.X
+		boxes[0].SetBounds (
+			handle.
+			Add(image.Pt(0, offset)).
+			Add(gutter.Min))
+	} else {
+		width  := gutter.Dx() - handle.Dx()
+		offset := int(float64(width) * this.value)
+		gutter.Max.Y = handle.Max.Y
+		boxes[0].SetBounds (
+			handle.
+			Add(image.Pt(offset, 0)).
+			Add(gutter.Min))
+	}
 }