widget: add semantic descriptions

Some semantic information is automatically extracted, but some must be
provided by UI components. This change enriches the generic and material
widgets with such information.

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

widget/bool.go

@@ -3,6 +3,7 @@
 package widget
 
 import (
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 )
 
@@ -37,10 +38,14 @@ func (b *Bool) History() []Press {
 }
 
 func (b *Bool) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions {
-	dims := b.clk.Layout(gtx, w)
+	dims := b.clk.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
-	for b.clk.Clicked() {
+		for b.clk.Clicked() {
-		b.Value = !b.Value
+			b.Value = !b.Value
-		b.changed = true
+			b.changed = true
-	}
+		}
+		semantic.SelectedOp(b.Value).Add(gtx.Ops)
+		semantic.DisabledOp(gtx.Queue == nil).Add(gtx.Ops)
+		return w(gtx)
+	})
 	return dims
 }

widget/button.go

@@ -9,6 +9,7 @@ import (
 	"gioui.org/f32"
 	"gioui.org/gesture"
 	"gioui.org/io/key"
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
@@ -97,6 +98,7 @@ func (b *Clickable) Layout(gtx layout.Context, w layout.Widget) layout.Dimension
 	dims := w(gtx)
 	c := m.Stop()
 	defer clip.Rect(image.Rectangle{Max: dims.Size}).Push(gtx.Ops).Pop()
+	semantic.DisabledOp(gtx.Queue == nil).Add(gtx.Ops)
 	b.click.Add(gtx.Ops)
 	c.Add(gtx.Ops)
 	for len(b.history) > 0 {

widget/enum.go

@@ -6,6 +6,7 @@ import (
 	"image"
 
 	"gioui.org/gesture"
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
@@ -76,6 +77,8 @@ func (e *Enum) Layout(gtx layout.Context, key string, content layout.Widget) lay
 		}
 		clk.Add(gtx.Ops)
 	}
+	semantic.SelectedOp(key == e.Value).Add(gtx.Ops)
+	semantic.DisabledOp(gtx.Queue == nil).Add(gtx.Ops)
 	c.Add(gtx.Ops)
 
 	return dims

widget/label.go

@@ -7,6 +7,7 @@ import (
 	"image"
 	"unicode/utf8"
 
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
@@ -184,6 +185,8 @@ func (l Label) Layout(gtx layout.Context, s text.Shaper, font text.Font, size un
 		rcl.Pop()
 		t.Pop()
 	}
+	defer clip.Rect(image.Rectangle{Max: dims.Size}).Push(gtx.Ops).Pop()
+	semantic.LabelOp(txt).Add(gtx.Ops)
 	return dims
 }
 

widget/material/button.go

@@ -9,6 +9,7 @@ import (
 
 	"gioui.org/f32"
 	"gioui.org/internal/f32color"
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
@@ -89,6 +90,7 @@ func IconButton(th *Theme, button *widget.Clickable, icon *widget.Icon, descript
 // decoration.
 func Clickable(gtx layout.Context, button *widget.Clickable, w layout.Widget) layout.Dimensions {
 	return button.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
+		semantic.Button.Add(gtx.Ops)
 		return layout.Stack{}.Layout(gtx,
 			layout.Expanded(func(gtx layout.Context) layout.Dimensions {
 				defer clip.Rect{Max: gtx.Constraints.Min}.Push(gtx.Ops).Pop()
@@ -118,6 +120,7 @@ func (b ButtonStyle) Layout(gtx layout.Context) layout.Dimensions {
 func (b ButtonLayoutStyle) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions {
 	min := gtx.Constraints.Min
 	return b.Button.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
+		semantic.Button.Add(gtx.Ops)
 		return layout.Stack{Alignment: layout.Center}.Layout(gtx,
 			layout.Expanded(func(gtx layout.Context) layout.Dimensions {
 				rr := float32(gtx.Px(b.CornerRadius))
@@ -149,6 +152,10 @@ func (b ButtonLayoutStyle) Layout(gtx layout.Context, w layout.Widget) layout.Di
 func (b IconButtonStyle) Layout(gtx layout.Context) layout.Dimensions {
 	m := op.Record(gtx.Ops)
 	dims := b.Button.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
+		semantic.Button.Add(gtx.Ops)
+		if d := b.Description; d != "" {
+			semantic.DescriptionOp(b.Description).Add(gtx.Ops)
+		}
 		return layout.Stack{Alignment: layout.Center}.Layout(gtx,
 			layout.Expanded(func(gtx layout.Context) layout.Dimensions {
 				sizex, sizey := gtx.Constraints.Min.X, gtx.Constraints.Min.Y

widget/material/checkbox.go

@@ -3,6 +3,7 @@
 package material
 
 import (
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/unit"
 	"gioui.org/widget"
@@ -32,6 +33,7 @@ func CheckBox(th *Theme, checkBox *widget.Bool, label string) CheckBoxStyle {
 // Layout updates the checkBox and displays it.
 func (c CheckBoxStyle) Layout(gtx layout.Context) layout.Dimensions {
 	return c.CheckBox.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
+		semantic.CheckBox.Add(gtx.Ops)
 		return c.layout(gtx, c.CheckBox.Value, c.CheckBox.Hovered())
 	})
 }

widget/material/editor.go

@@ -6,6 +6,7 @@ import (
 	"image/color"
 
 	"gioui.org/internal/f32color"
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/paint"
@@ -59,6 +60,7 @@ func (e EditorStyle) Layout(gtx layout.Context) layout.Dimensions {
 		gtx.Constraints.Min.Y = h
 	}
 	dims = e.Editor.Layout(gtx, e.shaper, e.Font, e.TextSize, func(gtx layout.Context) layout.Dimensions {
+		semantic.Editor.Add(gtx.Ops)
 		disabled := gtx.Queue == nil
 		if e.Editor.Len() > 0 {
 			paint.ColorOp{Color: blendDisabledColor(disabled, e.SelectionColor)}.Add(gtx.Ops)

widget/material/radiobutton.go

@@ -3,6 +3,7 @@
 package material
 
 import (
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/unit"
 	"gioui.org/widget"
@@ -38,6 +39,7 @@ func RadioButton(th *Theme, group *widget.Enum, key, label string) RadioButtonSt
 func (r RadioButtonStyle) Layout(gtx layout.Context) layout.Dimensions {
 	hovered, hovering := r.Group.Hovered()
 	return r.Group.Layout(gtx, r.Key, func(gtx layout.Context) layout.Dimensions {
+		semantic.RadioButton.Add(gtx.Ops)
 		return r.layout(gtx, r.Group.Value == r.Key, hovering && hovered == r.Key)
 	})
 }

widget/material/switch.go

@@ -8,6 +8,7 @@ import (
 
 	"gioui.org/f32"
 	"gioui.org/internal/f32color"
+	"gioui.org/io/semantic"
 	"gioui.org/layout"
 	"gioui.org/op"
 	"gioui.org/op/clip"
@@ -127,6 +128,10 @@ func (s SwitchStyle) Layout(gtx layout.Context) layout.Dimensions {
 	sz := image.Pt(clickSize, clickSize)
 	defer clip.Ellipse(f32.Rectangle{Max: layout.FPt(sz)}).Push(gtx.Ops).Pop()
 	s.Switch.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
+		if d := s.Description; d != "" {
+			semantic.DescriptionOp(d).Add(gtx.Ops)
+		}
+		semantic.Switch.Add(gtx.Ops)
 		return layout.Dimensions{Size: sz}
 	})
 

widget/widget_test.go

@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package widget_test
+
+import (
+	"image"
+	"testing"
+
+	"gioui.org/f32"
+	"gioui.org/io/pointer"
+	"gioui.org/io/router"
+	"gioui.org/io/semantic"
+	"gioui.org/io/system"
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/widget"
+)
+
+func TestBool(t *testing.T) {
+	var (
+		ops op.Ops
+		r   router.Router
+		b   widget.Bool
+	)
+	gtx := layout.NewContext(&ops, system.FrameEvent{Queue: &r})
+	layout := func() {
+		b.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
+			semantic.CheckBox.Add(gtx.Ops)
+			semantic.DescriptionOp("description").Add(gtx.Ops)
+			return layout.Dimensions{Size: image.Pt(100, 100)}
+		})
+	}
+	layout()
+	r.Frame(gtx.Ops)
+	r.Queue(
+		pointer.Event{
+			Source:   pointer.Touch,
+			Type:     pointer.Press,
+			Position: f32.Pt(50, 50),
+		},
+		pointer.Event{
+			Source:   pointer.Touch,
+			Type:     pointer.Release,
+			Position: f32.Pt(50, 50),
+		},
+	)
+	ops.Reset()
+	layout()
+	r.Frame(gtx.Ops)
+	tree := r.AppendSemantics(nil)
+	n := tree[0].Children[0].Desc
+	if n.Description != "description" {
+		t.Errorf("unexpected semantic description: %s", n.Description)
+	}
+	if n.Class != semantic.CheckBox {
+		t.Errorf("unexpected semantic class: %v", n.Class)
+	}
+	if !b.Value || !n.Selected {
+		t.Error("click did not select")
+	}
+}