layout: added Axis methods

Signed-off-by: pierre <pierre.curto@gmail.com>

layout/flex.go

@@ -3,8 +3,6 @@
 package layout
 
 import (
-	"image"
-
 	"gioui.org/op"
 )
 
@@ -83,8 +81,8 @@ func Flexed(weight float32, widget Widget) FlexChild {
 func (f Flex) Layout(gtx Context, children ...FlexChild) Dimensions {
 	size := 0
 	cs := gtx.Constraints
-	mainMin, mainMax := axisMainConstraint(f.Axis, cs)
-	crossMin, crossMax := axisCrossConstraint(f.Axis, cs)
+	mainMin, mainMax := f.Axis.mainConstraint(cs)
+	crossMin, crossMax := f.Axis.crossConstraint(cs)
 	remaining := mainMax
 	var totalWeight float32
 	cgtx := gtx
@@ -95,10 +93,10 @@ func (f Flex) Layout(gtx Context, children ...FlexChild) Dimensions {
 			continue
 		}
 		macro := op.Record(gtx.Ops)
-		cgtx.Constraints = axisConstraints(f.Axis, 0, remaining, crossMin, crossMax)
+		cgtx.Constraints = f.Axis.constraints(0, remaining, crossMin, crossMax)
 		dims := child.widget(cgtx)
 		c := macro.Stop()
-		sz := axisMain(f.Axis, dims.Size)
+		sz := f.Axis.Main(dims.Size)
 		size += sz
 		remaining -= sz
 		if remaining < 0 {
@@ -130,10 +128,10 @@ func (f Flex) Layout(gtx Context, children ...FlexChild) Dimensions {
 			}
 		}
 		macro := op.Record(gtx.Ops)
-		cgtx.Constraints = axisConstraints(f.Axis, flexSize, flexSize, crossMin, crossMax)
+		cgtx.Constraints = f.Axis.constraints(flexSize, flexSize, crossMin, crossMax)
 		dims := child.widget(cgtx)
 		c := macro.Stop()
-		sz := axisMain(f.Axis, dims.Size)
+		sz := f.Axis.Main(dims.Size)
 		size += sz
 		remaining -= sz
 		if remaining < 0 {
@@ -145,7 +143,7 @@ func (f Flex) Layout(gtx Context, children ...FlexChild) Dimensions {
 	var maxCross int
 	var maxBaseline int
 	for _, child := range children {
-		if c := axisCross(f.Axis, child.dims.Size); c > maxCross {
+		if c := f.Axis.Cross(child.dims.Size); c > maxCross {
 			maxCross = c
 		}
 		if b := child.dims.Size.Y - child.dims.Baseline; b > maxBaseline {
@@ -175,19 +173,19 @@ func (f Flex) Layout(gtx Context, children ...FlexChild) Dimensions {
 		var cross int
 		switch f.Alignment {
 		case End:
-			cross = maxCross - axisCross(f.Axis, dims.Size)
+			cross = maxCross - f.Axis.Cross(dims.Size)
 		case Middle:
-			cross = (maxCross - axisCross(f.Axis, dims.Size)) / 2
+			cross = (maxCross - f.Axis.Cross(dims.Size)) / 2
 		case Baseline:
 			if f.Axis == Horizontal {
 				cross = maxBaseline - b
 			}
 		}
 		stack := op.Push(gtx.Ops)
-		op.Offset(FPt(axisPoint(f.Axis, mainSize, cross))).Add(gtx.Ops)
+		op.Offset(FPt(f.Axis.point(mainSize, cross))).Add(gtx.Ops)
 		child.call.Add(gtx.Ops)
 		stack.Pop()
-		mainSize += axisMain(f.Axis, dims.Size)
+		mainSize += f.Axis.Main(dims.Size)
 		if i < len(children)-1 {
 			switch f.Spacing {
 			case SpaceEvenly:
@@ -215,58 +213,10 @@ func (f Flex) Layout(gtx Context, children ...FlexChild) Dimensions {
 			mainSize += space / (len(children) * 2)
 		}
 	}
-	sz := axisPoint(f.Axis, mainSize, maxCross)
+	sz := f.Axis.point(mainSize, maxCross)
 	return Dimensions{Size: sz, Baseline: sz.Y - maxBaseline}
 }
 
-func axisPoint(a Axis, main, cross int) image.Point {
-	if a == Horizontal {
-		return image.Point{main, cross}
-	} else {
-		return image.Point{cross, main}
-	}
-}
-
-func axisMain(a Axis, sz image.Point) int {
-	if a == Horizontal {
-		return sz.X
-	} else {
-		return sz.Y
-	}
-}
-
-func axisCross(a Axis, sz image.Point) int {
-	if a == Horizontal {
-		return sz.Y
-	} else {
-		return sz.X
-	}
-}
-
-func axisMainConstraint(a Axis, cs Constraints) (int, int) {
-	if a == Horizontal {
-		return cs.Min.X, cs.Max.X
-	} else {
-		return cs.Min.Y, cs.Max.Y
-	}
-}
-
-func axisCrossConstraint(a Axis, cs Constraints) (int, int) {
-	if a == Horizontal {
-		return cs.Min.Y, cs.Max.Y
-	} else {
-		return cs.Min.X, cs.Max.X
-	}
-}
-
-func axisConstraints(a Axis, mainMin, mainMax, crossMin, crossMax int) Constraints {
-	if a == Horizontal {
-		return Constraints{Min: image.Pt(mainMin, crossMin), Max: image.Pt(mainMax, crossMax)}
-	} else {
-		return Constraints{Min: image.Pt(crossMin, mainMin), Max: image.Pt(crossMax, mainMax)}
-	}
-}
-
 func (s Spacing) String() string {
 	switch s {
 	case SpaceEnd:

layout/layout.go

@@ -225,6 +225,57 @@ func (a Alignment) String() string {
 	}
 }
 
+// Main returns the main axis of p.
+// I.e. if a is Horizontal, then the returned value is p.X.
+func (a Axis) Main(p image.Point) int {
+	if a == Horizontal {
+		return p.X
+	}
+	return p.Y
+}
+
+// Cross returns the cross axis of p.
+// I.e. if a is Horizontal, then the returned value is p.Y.
+func (a Axis) Cross(p image.Point) int {
+	if a == Horizontal {
+		return p.Y
+	}
+	return p.X
+}
+
+// point returns the point having its values set based on the axis.
+// I.e. if a is Horizontal, then the returned value is image.Point{X: main, Y: cross}.
+func (a Axis) point(main, cross int) image.Point {
+	if a == Horizontal {
+		return image.Pt(main, cross)
+	}
+	return image.Pt(cross, main)
+}
+
+// mainConstraint returns the min and max main constraints for axis a.
+func (a Axis) mainConstraint(cs Constraints) (int, int) {
+	if a == Horizontal {
+		return cs.Min.X, cs.Max.X
+	}
+	return cs.Min.Y, cs.Max.Y
+}
+
+// crossConstraint returns the min and max cross constraints for axis a.
+func (a Axis) crossConstraint(cs Constraints) (int, int) {
+	if a == Horizontal {
+		return cs.Min.Y, cs.Max.Y
+	}
+	return cs.Min.X, cs.Max.X
+}
+
+// constraints returns the constraints for axis a.
+func (a Axis) constraints(mainMin, mainMax, crossMin, crossMax int) Constraints {
+	if a == Horizontal {
+		return Constraints{Min: image.Pt(mainMin, crossMin), Max: image.Pt(mainMax, crossMax)}
+	}
+	return Constraints{Min: image.Pt(crossMin, mainMin), Max: image.Pt(crossMax, mainMax)}
+}
+
 func (a Axis) String() string {
 	switch a {
 	case Horizontal:

layout/list.go

@@ -98,8 +98,8 @@ func (l *List) init(gtx Context, len int) {
 // Layout the List.
 func (l *List) Layout(gtx Context, len int, w ListElement) Dimensions {
 	l.init(gtx, len)
-	crossMin, crossMax := axisCrossConstraint(l.Axis, gtx.Constraints)
-	gtx.Constraints = axisConstraints(l.Axis, 0, inf, crossMin, crossMax)
+	crossMin, crossMax := l.Axis.crossConstraint(gtx.Constraints)
+	gtx.Constraints = l.Axis.constraints(0, inf, crossMin, crossMax)
 	macro := op.Record(gtx.Ops)
 	for l.next(); l.more(); l.next() {
 		child := op.Record(gtx.Ops)
@@ -155,7 +155,7 @@ func (l *List) more() bool {
 }
 
 func (l *List) nextDir() iterationDir {
-	_, vsize := axisMainConstraint(l.Axis, l.cs)
+	_, vsize := l.Axis.mainConstraint(l.cs)
 	last := l.Position.First + len(l.children)
 	// Clamp offset.
 	if l.maxSize-l.Position.Offset < vsize && last == l.len {
@@ -178,7 +178,7 @@ func (l *List) nextDir() iterationDir {
 // End the current child by specifying its dimensions.
 func (l *List) end(dims Dimensions, call op.CallOp) {
 	child := scrollChild{dims.Size, call}
-	mainSize := axisMain(l.Axis, child.size)
+	mainSize := l.Axis.Main(child.size)
 	l.maxSize += mainSize
 	switch l.dir {
 	case iterateForward:
@@ -200,12 +200,12 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 	if l.more() {
 		panic("unfinished child")
 	}
-	mainMin, mainMax := axisMainConstraint(l.Axis, l.cs)
+	mainMin, mainMax := l.Axis.mainConstraint(l.cs)
 	children := l.children
 	// Skip invisible children
 	for len(children) > 0 {
 		sz := children[0].size
-		mainSize := axisMain(l.Axis, sz)
+		mainSize := l.Axis.Main(sz)
 		if l.Position.Offset <= mainSize {
 			break
 		}
@@ -217,10 +217,10 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 	var maxCross int
 	for i, child := range children {
 		sz := child.size
-		if c := axisCross(l.Axis, sz); c > maxCross {
+		if c := l.Axis.Cross(sz); c > maxCross {
 			maxCross = c
 		}
-		size += axisMain(l.Axis, sz)
+		size += l.Axis.Main(sz)
 		if size >= mainMax {
 			children = children[:i+1]
 			break
@@ -236,11 +236,11 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 		var cross int
 		switch l.Alignment {
 		case End:
-			cross = maxCross - axisCross(l.Axis, sz)
+			cross = maxCross - l.Axis.Cross(sz)
 		case Middle:
-			cross = (maxCross - axisCross(l.Axis, sz)) / 2
+			cross = (maxCross - l.Axis.Cross(sz)) / 2
 		}
-		childSize := axisMain(l.Axis, sz)
+		childSize := l.Axis.Main(sz)
 		max := childSize + pos
 		if max > mainMax {
 			max = mainMax
@@ -250,12 +250,12 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 			min = 0
 		}
 		r := image.Rectangle{
-			Min: axisPoint(l.Axis, min, -inf),
-			Max: axisPoint(l.Axis, max, inf),
+			Min: l.Axis.point(min, -inf),
+			Max: l.Axis.point(max, inf),
 		}
 		stack := op.Push(ops)
 		clip.Rect(r).Add(ops)
-		op.Offset(FPt(axisPoint(l.Axis, pos, cross))).Add(ops)
+		op.Offset(FPt(l.Axis.point(pos, cross))).Add(ops)
 		child.call.Add(ops)
 		stack.Pop()
 		pos += childSize
@@ -272,7 +272,7 @@ func (l *List) layout(ops *op.Ops, macro op.MacroOp) Dimensions {
 	if pos > mainMax {
 		pos = mainMax
 	}
-	dims := axisPoint(l.Axis, pos, maxCross)
+	dims := l.Axis.point(pos, maxCross)
 	call := macro.Stop()
 	defer op.Push(ops).Pop()
 	pointer.Rect(image.Rectangle{Max: dims}).Add(ops)