all: rename c to gtx for *layout.Context parameters

Short like `ctx` but not as easily confused with context.Context
values.

Suggested by Larry Clapp.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/layout/flex.go

@@ -68,12 +68,12 @@ const (
 )
 
 // Init must be called before Rigid or Flexible.
-func (f *Flex) Init(c *Context) *Flex {
+func (f *Flex) Init(gtx *Context) *Flex {
 	if f.mode > modeBegun {
 		panic("must End the current child before calling Init again")
 	}
 	f.mode = modeBegun
-	f.ctx = c
+	f.ctx = gtx
 	f.size = 0
 	f.rigidSize = 0
 	f.maxCross = 0

ui/layout/layout.go

@@ -133,12 +133,12 @@ type Inset struct {
 type Align Direction
 
 // Layout a widget.
-func (in Inset) Layout(c *Context, w Widget) {
-	top := c.Px(in.Top)
-	right := c.Px(in.Right)
-	bottom := c.Px(in.Bottom)
-	left := c.Px(in.Left)
-	mcs := c.Constraints
+func (in Inset) Layout(gtx *Context, w Widget) {
+	top := gtx.Px(in.Top)
+	right := gtx.Px(in.Right)
+	bottom := gtx.Px(in.Bottom)
+	left := gtx.Px(in.Left)
+	mcs := gtx.Constraints
 	mcs.Width.Min -= left + right
 	mcs.Width.Max -= left + right
 	if mcs.Width.Min < 0 {
@@ -156,12 +156,12 @@ func (in Inset) Layout(c *Context, w Widget) {
 		mcs.Height.Max = mcs.Height.Min
 	}
 	var stack ui.StackOp
-	stack.Push(c.Ops)
-	ui.TransformOp{}.Offset(toPointF(image.Point{X: left, Y: top})).Add(c.Ops)
-	dims := c.Layout(mcs, w)
+	stack.Push(gtx.Ops)
+	ui.TransformOp{}.Offset(toPointF(image.Point{X: left, Y: top})).Add(gtx.Ops)
+	dims := gtx.Layout(mcs, w)
 	stack.Pop()
-	c.Dimensions = Dimensions{
-		Size:     c.Constraints.Constrain(dims.Size.Add(image.Point{X: right + left, Y: top + bottom})),
+	gtx.Dimensions = Dimensions{
+		Size:     gtx.Constraints.Constrain(dims.Size.Add(image.Point{X: right + left, Y: top + bottom})),
 		Baseline: dims.Baseline + top,
 	}
 }
@@ -173,14 +173,14 @@ func UniformInset(v ui.Value) Inset {
 }
 
 // Layout a widget.
-func (a Align) Layout(c *Context, w Widget) {
+func (a Align) Layout(gtx *Context, w Widget) {
 	var macro ui.MacroOp
-	macro.Record(c.Ops)
-	cs := c.Constraints
+	macro.Record(gtx.Ops)
+	cs := gtx.Constraints
 	mcs := cs
 	mcs.Width.Min = 0
 	mcs.Height.Min = 0
-	dims := c.Layout(mcs, w)
+	dims := gtx.Layout(mcs, w)
 	macro.Stop()
 	sz := dims.Size
 	if sz.X < cs.Width.Min {
@@ -203,11 +203,11 @@ func (a Align) Layout(c *Context, w Widget) {
 		p.Y = sz.Y - dims.Size.Y
 	}
 	var stack ui.StackOp
-	stack.Push(c.Ops)
-	ui.TransformOp{}.Offset(toPointF(p)).Add(c.Ops)
-	macro.Add(c.Ops)
+	stack.Push(gtx.Ops)
+	ui.TransformOp{}.Offset(toPointF(p)).Add(gtx.Ops)
+	macro.Add(gtx.Ops)
 	stack.Pop()
-	c.Dimensions = Dimensions{
+	gtx.Dimensions = Dimensions{
 		Size:     sz,
 		Baseline: dims.Baseline,
 	}

ui/layout/list.go

@@ -67,11 +67,11 @@ const (
 const inf = 1e6
 
 // Init prepares the list for iterating through its children with Next.
-func (l *List) init(c *Context, len int) {
+func (l *List) init(gtx *Context, len int) {
 	if l.more() {
 		panic("unfinished child")
 	}
-	l.ctx = c
+	l.ctx = gtx
 	l.maxSize = 0
 	l.children = l.children[:0]
 	l.len = len
@@ -84,20 +84,20 @@ func (l *List) init(c *Context, len int) {
 		l.offset = 0
 		l.first = len
 	}
-	l.macro.Record(c.Ops)
+	l.macro.Record(gtx.Ops)
 	l.next()
 }
 
 // Layout the List and return its dimensions.
-func (l *List) Layout(c *Context, len int, w ListElement) {
-	for l.init(c, len); l.more(); l.next() {
+func (l *List) Layout(gtx *Context, len int, w ListElement) {
+	for l.init(gtx, len); l.more(); l.next() {
 		cs := axisConstraints(l.Axis, Constraint{Max: inf}, axisCrossConstraint(l.Axis, l.ctx.Constraints))
 		i := l.index()
-		l.end(c.Layout(cs, func() {
+		l.end(gtx.Layout(cs, func() {
 			w(i)
 		}))
 	}
-	c.Dimensions = l.layout()
+	gtx.Dimensions = l.layout()
 }
 
 func (l *List) scrollToEnd() bool {

ui/layout/stack.go

@@ -29,8 +29,8 @@ type StackChild struct {
 }
 
 // Init a stack before calling Rigid or Expand.
-func (s *Stack) Init(c *Context) *Stack {
-	s.ctx = c
+func (s *Stack) Init(gtx *Context) *Stack {
+	s.ctx = gtx
 	s.constrained = true
 	s.maxSZ = image.Point{}
 	s.baseline = 0