Made the Cut layout significantly more powerful

layouts/cut.go

@@ -5,87 +5,46 @@ 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
+	branches []*Cut
+	expand   []bool
 	vertical bool
 }
 
-// Vertical divides the layout in equal halves vertically.
-func (this *Cut) Vertical () (top, bottom *Cut) {
-	this.fill()
-	this.even()
+// 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
-	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) {
+// 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()
-	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]
+// 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[0] != nil && this.branches[1] != nil
+	return this != nil && this.branches != nil
 }
 
 func (this *Cut) fill () {
-	this.branches[0] = &Cut { }
-	this.branches[1] = &Cut { }
+	this.branches = make([]*Cut, len(this.expand))
+	for index := range this.branches {
+		this.branches[index] = new(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 {
@@ -126,9 +85,11 @@ func (this *Cut) minimumSize (hints tomo.LayoutHints, boxes []tomo.Box) (image.P
 }
 
 func (this *Cut) arrange (hints tomo.LayoutHints, boxes []tomo.Box) []tomo.Box {
+	nChildren := len(this.branches)
+
 	// collect minimum sizes and physical endpoints
-	var minimums [2]image.Point
-	var leaves   [2]tomo.Box
+	var minimums = make([]image.Point,  nChildren)
+	var leaves   = make([]tomo.Box,     nChildren)
 	var nBranches int
 	remaining := boxes
 	for index, branch := range this.branches {
@@ -163,7 +124,7 @@ func (this *Cut) arrange (hints tomo.LayoutHints, boxes []tomo.Box) []tomo.Box {
 	expandingSize := freeSpace / nExpanding
 
 	// calculate the size and position of branches
-	var bounds [2]image.Rectangle
+	var bounds = make([]image.Rectangle, nChildren)
 	x := float64(hints.Bounds.Min.X)
 	y := float64(hints.Bounds.Min.Y)
 	for index, minimum := range minimums {