Change Layout() type to Layout(Context) Context

main.go

@@ -23,12 +23,14 @@ type Context struct {
 	cs layout.Constraints
 	dims layout.Dimens
 	faces measure.Faces
+	extra map[string]interface{}
 }
 
-func NewContext(w *app.Window) *Context {
-	return &Context{
+func NewContext(w *app.Window) Context {
+	return Context{
 		ops: new(ui.Ops),
 		q: w.Queue(),
+		extra: make(map[string]interface{}),
 	}
 }
 
@@ -39,36 +41,53 @@ func (ctx *Context) Reset(e app.DrawEvent) {
 	ctx.faces.Reset(ctx.c)
 }
 
-func (fw fWidget) Layout(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
-	return fw.l(c, q, ops, cs)
+func (fw fWidget) Layout(ctx Context) Context {
+	return fw.l(ctx)
 }
 
 type Widget interface {
-	Layout(ui.Config, input.Queue, *ui.Ops, layout.Constraints) layout.Dimens
+	Layout(Context) Context
 }
 
+type WidgetCombinator func(...Widget) Widget
+
 type fWidget struct {
 	l Layout
 }
 
-type WidgetCombinator func(...Widget) Widget
-
-type Layout func(ui.Config, input.Queue, *ui.Ops, layout.Constraints) layout.Dimens
+type Layout func(Context) Context
 
 type LayoutCombinator func(...Layout) Layout
 
-func (ctx *Context) Do(ls ...Layout) {
+func LayoutWithContext(ctx Context, ls ...Layout) Context {
 	for _, l := range ls {
-		ctx.dims = l(ctx.c, ctx.q, ctx.ops, ctx.cs)
+		ctx = l(ctx)
 	}
+	return ctx
 }
 
 type Label struct {
 	l *text.Label
 }
 
-func (l *Label) Layout(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
-	return l.l.Layout(ops, cs)
+func (l *Label) Layout(ctx Context) Context {
+	ctx.dims = l.l.Layout(ctx.ops, ctx.cs)
+	return ctx
+}
+
+type Editor struct {
+	e *text.Editor
+}
+
+func NewEditor(face text.Face, singleline bool) *Editor {
+	ret := &Editor{}
+	ret.e = &text.Editor{ Face: face, SingleLine: singleline }
+	return ret
+}
+
+func (e *Editor) Layout(ctx Context) Context {
+	ctx.dims = e.e.Layout(ctx.c, ctx.q, ctx.ops, ctx.cs)
+	return ctx
 }
 
 func main() {
@@ -80,21 +99,16 @@ func main() {
 		}
 		ctx := NewContext(w)
 		t := time.NewTicker(time.Second/30)
-		e1 := &text.Editor{
-			Face: ctx.faces.For(regular, ui.Sp(24)),
-			SingleLine: true,
-		}
-		e1.SetText("hi there")
-		e1.Focus()
+		e1 := NewEditor(ctx.faces.For(regular, ui.Sp(24)), true)
+		e1.e.SetText("hi there")
+		e1.e.Focus()
 
-		e2 := &text.Editor{
-			Face: ctx.faces.For(regular, ui.Sp(24)),
-			SingleLine: true,
-		}
-		e2.SetText("ok bye")
-		f := Flex(layout.Vertical, layout.Start, layout.Start)
-		ins10a := Inset(ui.Dp(10),ui.Dp(10),ui.Dp(10),ui.Dp(10))
-		ins10b := Inset(ui.Dp(10),ui.Dp(10),ui.Dp(10),ui.Dp(10))
+		e2 := NewEditor( ctx.faces.For(regular, ui.Sp(24)), true)
+		e2.e.SetText("ok bye")
+
+		f := NewFlex(layout.Vertical, layout.Start, layout.Start)
+		ins10a := NewInset(ui.Dp(10),ui.Dp(10),ui.Dp(10),ui.Dp(10))
+		ins10b := NewInset(ui.Dp(10),ui.Dp(10),ui.Dp(10),ui.Dp(10))
 
 		btn := &Label{}
 		btn.l = &text.Label{
@@ -113,11 +127,13 @@ func main() {
 					return
 				case app.DrawEvent:
 					ctx.Reset(e)
-					ctx.Do(
+					LayoutWithContext(ctx,
 						ins10a(f(
-							FlexChild{10,e1},
-							FlexChild{5,ins10b(e2)},
-							FlexChild{1,btn},
+							e1,
+							Flexible(5),
+							ins10b(e2),
+							Flexible(10),
+							btn,
 						)).Layout)
 					w.Draw(ctx.ops)
 				}
@@ -132,43 +148,60 @@ type FlexChild struct {
 	w Widget
 }
 
-func Flex(axis layout.Axis, mainAxisAlignment layout.MainAxisAlignment, crossAxisAlignment layout.CrossAxisAlignment) func(...FlexChild) Widget {
+func Flexible(v float32) Widget {
+	ret := fWidget{}
+	ret.l = func(ctx Context) Context {
+		ctx.extra["Flexible"] = v
+		return ctx
+	}
+	return ret
+}
+
+func NewFlex(axis layout.Axis, mainAxisAlignment layout.MainAxisAlignment, crossAxisAlignment layout.CrossAxisAlignment) WidgetCombinator {
 	f := layout.Flex{
 		Axis: axis,
 		MainAxisAlignment: mainAxisAlignment,
 		CrossAxisAlignment: crossAxisAlignment,
 	}
-	return func(ws ...FlexChild) Widget {
+	return func(ws ...Widget) Widget {
 		ret := fWidget{}
-		ret.l = func(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
-			f.Init(ops, cs)
-			cs = f.Rigid()
-			var dims layout.Dimens
+		ret.l = func(ctx Context) Context {
+			f.Init(ctx.ops, ctx.cs)
 			fcs := make([]layout.FlexChild,len(ws))
 			for i, w := range ws {
-				if i > 0 {
-					cs = f.Flexible(w.x)
+				if v,ok := ctx.extra["Flexible"]; ok {
+					switch v := v.(type) {
+					case float32:
+						ctx.cs = f.Flexible(v)
+					default:
+						log.Fatal("Type error")
+					}
+				} else {
+					ctx.cs = f.Rigid()
 				}
-				dims = w.w.Layout(c, q, ops, cs)
-				fcs[i] = f.End(dims)
+				ctx = w.Layout(ctx)
+				fcs[i] = f.End(ctx.dims)
 			}
-			return f.Layout(fcs...)
+			ctx.dims = f.Layout(fcs...)
+			delete(ctx.extra, "Flexible")
+			return ctx
 		}
 		return ret
 	}
 }
 
-func Inset(top, right, bottom, left ui.Value) WidgetCombinator {
+func NewInset(top, right, bottom, left ui.Value) WidgetCombinator {
 	ins := layout.Inset{ Top: top, Right: right, Bottom: bottom, Left: left }
 	return func(ws ...Widget) Widget {
 		ret := fWidget{}
-		ret.l = func(c ui.Config, q input.Queue, ops *ui.Ops, cs layout.Constraints) layout.Dimens {
-			cs = ins.Begin(c, ops, cs)
+		ret.l = func(ctx Context) Context {
+			ctx.cs = ins.Begin(ctx.c, ctx.ops, ctx.cs)
 			var dims layout.Dimens
 			for _, w := range ws {
-				dims = w.Layout(c, q, ops, cs)
+				ctx = w.Layout(ctx)
 			}
-			return ins.End(dims)
+			ctx.dims = ins.End(dims)
+			return ctx
 		}
 		return ret
 	}