Functional options.

cmd/hello/main.go

@@ -16,6 +16,12 @@ import (
 	"golang.org/x/image/font/gofont/goregular"
 )
 
+func NewButton(face text.Face, t string, c color.RGBA) giowrap.Clickable {
+	lbl := giowrap.NewLabel(t, giowrap.LabelFace(face), giowrap.LabelAlignment(text.Center))
+	bg := giowrap.NewBackground(giowrap.BgColor(c), giowrap.BgRadius(ui.Dp(4)))
+	return giowrap.AsClickable(bg(lbl))
+}
+
 func main() {
 	go func() {
 		w := app.NewWindow(nil)
@@ -25,24 +31,21 @@ func main() {
 		}
 		ctx := giowrap.NewContext(w)
 		t := time.NewTicker(time.Second/30)
-		e1 := giowrap.NewEditor(ctx.Faces.For(regular, ui.Sp(24)), true)
+		e1 := giowrap.NewEditor("text 1",giowrap.EditorFace(ctx.Faces.For(regular, ui.Sp(24))))
-		e1.SetText("text 1")
 		e1.Focus()
 
-		e2 := giowrap.NewEditor(ctx.Faces.For(regular, ui.Sp(24)), true)
+		e2 := giowrap.NewEditor("text 2",giowrap.EditorFace(ctx.Faces.For(regular, ui.Sp(24))))
-		e2.SetText("text 2")
 
-		f := giowrap.NewFlex(layout.Vertical, layout.Start, layout.Start)
+		f1 := giowrap.NewFlex(giowrap.FlexAxis(layout.Vertical))
-		OuterInset := giowrap.NewInset(ui.Dp(10),ui.Dp(10),ui.Dp(10),ui.Dp(10))
+		OuterInset := giowrap.NewInset(giowrap.InsetSize(ui.Dp(10)))
-		InnerInset := giowrap.NewInset(ui.Dp(10),ui.Dp(10),ui.Dp(10),ui.Dp(10))
+		InnerInset := giowrap.NewInset(giowrap.InsetSize(ui.Dp(10)))
 
-		lbl := giowrap.NewLabel(
+		f2 := giowrap.NewFlex(giowrap.FlexAxis(layout.Horizontal))
-			ctx.Faces.For(regular, ui.Sp(24)),
+
-			"push",
+		btn1 := NewButton(ctx.Faces.For(regular, ui.Sp(24)),
-			text.Center,
+			"push1", color.RGBA{A: 0xff, R: 0x3c, G: 0x98, B: 0xc6})
-		)
+		btn2 := NewButton(ctx.Faces.For(regular, ui.Sp(24)),
-		bg := giowrap.NewBackground(color.RGBA{A: 0xff, R: 0x3c, G: 0x98, B: 0xc6}, ui.Dp(4))
+			"push2", color.RGBA{A: 0xff, R: 0x3c, G: 0x98, B: 0xc6})
-		btn := giowrap.Clickable(bg(lbl))
 
 		for {
 			select {
@@ -55,15 +58,22 @@ func main() {
 				case app.DrawEvent:
 					ctx = ctx.Reset(e)
 					ctx = OuterInset(
-						    f(
+						    f1(
 							e1,
 							giowrap.Flexible(5),
 							InnerInset(e2),
 							giowrap.Flexible(10),
-							btn,
+							f2(
+								InnerInset(btn1),
+								giowrap.Flexible(1),
+								InnerInset(btn2),
+							),
 						)).Layout(ctx)
 					ctx.Draw()
-					if btn.Clicked(ctx) {
+					if btn1.Clicked(ctx) {
+						log.Print("Clicked: " + e1.Text() )
+					}
+					if btn2.Clicked(ctx) {
 						log.Print("Clicked: " + e2.Text() )
 					}
 				}

main.go

@@ -2,7 +2,8 @@ package giowrap
 
 import (
 	"image/color"
-	"log"
+	//"log"
+	"sync"
 
 	"gioui.org/ui"
 	"gioui.org/ui/app"
@@ -17,6 +18,24 @@ import (
 	"gioui.org/ui/pointer"
 )
 
+type Extra struct {
+	cur, max int
+	sync.Mutex
+	data []interface{}
+}
+
+var extra Extra
+
+func (e *Extra) New() int {
+	e.Lock()
+	if e.data == nil { e.data = make([]interface{},0) }
+	ret := e.max
+	e.max = e.max + 1
+	e.data = append(e.data,nil)
+	e.Unlock()
+	return ret
+}
+
 type Context struct {
 	Faces measure.Faces
 
@@ -26,16 +45,15 @@ type Context struct {
 	ops *ui.Ops
 	cs layout.Constraints
 	dims layout.Dimens
-	extra map[string]interface{}
 }
 
 func NewContext(w *app.Window) Context {
-	return Context{
+	ret := Context{
 		w: w,
 		ops: new(ui.Ops),
 		q: w.Queue(),
-		extra: make(map[string]interface{}),
 	}
+	return ret
 }
 
 func (ctx Context) Reset(e app.DrawEvent) Context {
@@ -62,12 +80,26 @@ type Label struct {
 	l *text.Label
 }
 
-func NewLabel(face text.Face, t string, alignment text.Alignment) *Label {
+type LabelOpts struct {
+	face text.Face
+	alignment text.Alignment
+}
+type LabelOption func(*LabelOpts)
+func LabelFace(x text.Face) LabelOption {
+	return func(o *LabelOpts) { o.face = x }
+}
+func LabelAlignment(x text.Alignment) LabelOption {
+	return func(o *LabelOpts) { o.alignment = x }
+}
+
+func NewLabel(t string, lops ...LabelOption) *Label {
 	ret := &Label{}
+	opts := &LabelOpts{}
+	for _,o := range lops { o(opts) }
 	ret.l = &text.Label{
-		Face: face,
+		Face: opts.face,
 		Text: t,
-		Alignment: alignment,
+		Alignment: opts.alignment,
 	}
 	return ret
 }
@@ -81,9 +113,24 @@ type Editor struct {
 	e *text.Editor
 }
 
-func NewEditor(face text.Face, singleline bool) *Editor {
+type EditorOpts struct {
+	face text.Face
+	singleline bool
+}
+type EditorOption func(*EditorOpts)
+func EditorFace(x text.Face) EditorOption {
+	return func(o *EditorOpts) { o.face = x }
+}
+func EditorSingleline() EditorOption {
+	return func(o *EditorOpts) { o.singleline = true }
+}
+
+func NewEditor(t string, eops ...EditorOption) *Editor {
 	ret := &Editor{}
-	ret.e = &text.Editor{ Face: face, SingleLine: singleline }
+	opts := &EditorOpts{}
+	for _,o := range eops { o(opts) }
+	ret.e = &text.Editor{ Face: opts.face, SingleLine: opts.singleline }
+	ret.SetText(t)
 	return ret
 }
 
@@ -110,33 +157,56 @@ func (fw fWidget) Layout(ctx Context) Context {
 
 type Flex WidgetCombinator
 
-// This "Widget" does nothing except set the Flexible key of ctx.extra.
+// This "Widget" does nothing except set the Flexible field of a FlexOpts
+// struct within the Extra data structure
 func Flexible(v float32) Widget {
 	return NewfWidget(func(ctx Context) Context {
-		ctx.extra["Flexible"] = v
+		extra.data[extra.cur].(*FlexOpts).flexible = v
 		return ctx
 	})
 }
 
+type FlexOpts struct {
+	axis layout.Axis
+	mainAxisAlignment layout.MainAxisAlignment
+	crossAxisAlignment layout.CrossAxisAlignment
+	flexible float32
+}
+
+type FlexOption func(*FlexOpts)
+
+func FlexAxis(x layout.Axis) FlexOption {
+	return func(o *FlexOpts) { o.axis = x }
+}
+
+func MainAxisAlignment(x layout.MainAxisAlignment) FlexOption {
+	return func(o *FlexOpts) { o.mainAxisAlignment = x }
+}
+func CrossAxisAlignment(x layout.CrossAxisAlignment) FlexOption {
+	return func(o *FlexOpts) { o.crossAxisAlignment = x }
+}
+
 // NewFlex returns a WidgetCombinator that wraps the layout.Flex element.
-func NewFlex(axis layout.Axis, mainAxisAlignment layout.MainAxisAlignment, crossAxisAlignment layout.CrossAxisAlignment) Flex {
+func NewFlex(fos ...FlexOption) Flex {
+	opts := &FlexOpts{}
+	for _,o := range fos { o(opts) }
 	f := layout.Flex{
-		Axis: axis,
+		Axis: opts.axis,
-		MainAxisAlignment: mainAxisAlignment,
+		MainAxisAlignment: opts.mainAxisAlignment,
-		CrossAxisAlignment: crossAxisAlignment,
+		CrossAxisAlignment: opts.crossAxisAlignment,
 	}
+	index := extra.New()
+	extra.data[index] = opts
+
 	return func(ws ...Widget) Widget {
 		return NewfWidget(func(ctx Context) Context {
+			extra.cur = index
+			opts := extra.data[index].(*FlexOpts)
 			f.Init(ctx.ops, ctx.cs)
 			fcs := make([]layout.FlexChild,len(ws))
 			for i, w := range ws {
-				if v,ok := ctx.extra["Flexible"]; ok {
+				if v := opts.flexible; v != 0 {
-					switch v := v.(type) {
+					ctx.cs = f.Flexible(v)
-					case float32:
-						ctx.cs = f.Flexible(v)
-					default:
-						log.Fatal("Type error")
-					}
 				} else {
 					ctx.cs = f.Rigid()
 				}
@@ -144,15 +214,43 @@ func NewFlex(axis layout.Axis, mainAxisAlignment layout.MainAxisAlignment, cross
 				fcs[i] = f.End(ctx.dims)
 			}
 			ctx.dims = f.Layout(fcs...)
-			delete(ctx.extra, "Flexible")
 			return ctx
 		})
 	}
 }
 
+type InsetOpts struct {
+	top, right, bottom, left ui.Value
+}
+
+type InsetOption func(*InsetOpts)
+
+func InsetTop(x ui.Value) InsetOption {
+	return func(o *InsetOpts) { o.top = x }
+}
+func InsetRight(x ui.Value) InsetOption {
+	return func(o *InsetOpts) { o.right = x }
+}
+func InsetBottom(x ui.Value) InsetOption {
+	return func(o *InsetOpts) { o.bottom = x }
+}
+func InsetLeft(x ui.Value) InsetOption {
+	return func(o *InsetOpts) { o.left = x }
+}
+func InsetSize(x ui.Value) InsetOption {
+	return func(o *InsetOpts) {
+		o.top = x
+		o.right = x
+		o.bottom = x
+		o.left = x
+	}
+}
+
 //NewInset returns a WidgetCombinator that wraps the layout.Inset element.
-func NewInset(top, right, bottom, left ui.Value) WidgetCombinator {
+func NewInset(insos ...InsetOption) WidgetCombinator {
-	ins := layout.Inset{ Top: top, Right: right, Bottom: bottom, Left: left }
+	opts := &InsetOpts{}
+	for _,o := range insos { o(opts) }
+	ins := layout.Inset{ Top: opts.top, Right: opts.right, Bottom: opts.bottom, Left: opts.left }
 	return func(ws ...Widget) Widget {
 		return NewfWidget(func(ctx Context) Context {
 			ctx.cs = ins.Begin(ctx.c, ctx.ops, ctx.cs)
@@ -190,12 +288,27 @@ func Enclose(e Enclosure, ws ...Widget) Widget {
 	})
 }
 
-func NewBackground(color color.RGBA, radius ui.Value) WidgetCombinator {
+type BackgroundOpts struct {
+	c color.RGBA
+	radius ui.Value
+}
+
+type BackgroundOption func(*BackgroundOpts)
+func BgColor(c color.RGBA) BackgroundOption {
+	return func(o *BackgroundOpts) { o.c = c }
+}
+func BgRadius(x ui.Value) BackgroundOption {
+	return func(o *BackgroundOpts) { o.radius = x }
+}
+
+func NewBackground(bos ...BackgroundOption) WidgetCombinator {
+	opts := &BackgroundOpts{}
+	for _,o := range bos { o(opts) }
 	bg := &Background{
-		Color: color,
+		Color: opts.c,
-		Radius: radius,
+		Radius: opts.radius,
-		Inset: layout.UniformInset(radius), 	// FIXME: need to be able to
+		Inset: layout.UniformInset(opts.radius),
-	}						// do math ops on Values
+	}
 	return func(ws ...Widget) Widget {
 		return Enclose(bg, ws...)
 	}
@@ -244,6 +357,11 @@ func rrect(ops *ui.Ops, width, height, se, sw, nw, ne float32) {
 	b.End()
 }
 
+type Clickable interface {
+	Widget
+	Clicked(Context) bool
+}
+
 //cWidget is a clickable Widget that provides the Clicked() method.
 type cWidget struct {
 	w Widget
@@ -267,6 +385,6 @@ func (w cWidget) Clicked(ctx Context) bool {
 }
 
 //Clickable converts any Widget into a clickable Widget.
-func Clickable(w Widget) cWidget {
+func AsClickable(w Widget) cWidget {
 	return cWidget{ w: w, click: new(gesture.Click) }
 }