widget,widget/material: remove Color field from Icon

Icons are meant to be shared among multiple widgets, but their Color
state may end up with unexpected values after use. Replace the state
with and explicit argument to Layout.

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

widget/icon.go

@@ -18,7 +18,6 @@ import (
 )
 
 type Icon struct {
-	Color color.NRGBA
 	src []byte
 	// Cached values.
 	op       paint.ImageOp
@@ -34,11 +33,11 @@ func NewIcon(data []byte) (*Icon, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &Icon{src: data, Color: color.NRGBA{A: 0xff}}, nil
+	return &Icon{src: data}, nil
 }
 
 // Layout displays the icon with its size set to the X minimum constraint.
-func (ic *Icon) Layout(gtx layout.Context) layout.Dimensions {
+func (ic *Icon) Layout(gtx layout.Context, color color.NRGBA) layout.Dimensions {
 	sz := gtx.Constraints.Min.X
 	if sz == 0 {
 		sz = gtx.Metric.Px(defaultIconSize)
@@ -47,7 +46,7 @@ func (ic *Icon) Layout(gtx layout.Context) layout.Dimensions {
 	defer op.Save(gtx.Ops).Load()
 	clip.Rect{Max: size}.Add(gtx.Ops)
 
-	ico := ic.image(size.X)
+	ico := ic.image(size.X, color)
 	ico.Add(gtx.Ops)
 	paint.PaintOp{}.Add(gtx.Ops)
 	return layout.Dimensions{
@@ -55,8 +54,8 @@ func (ic *Icon) Layout(gtx layout.Context) layout.Dimensions {
 	}
 }
 
-func (ic *Icon) image(sz int) paint.ImageOp {
-	if sz == ic.imgSize && ic.Color == ic.imgColor {
+func (ic *Icon) image(sz int, color color.NRGBA) paint.ImageOp {
+	if sz == ic.imgSize && color == ic.imgColor {
 		return ic.op
 	}
 	m, _ := iconvg.DecodeMetadata(ic.src)
@@ -64,12 +63,12 @@ func (ic *Icon) image(sz int) paint.ImageOp {
 	img := image.NewRGBA(image.Rectangle{Max: image.Point{X: sz, Y: int(float32(sz) * dy / dx)}})
 	var ico iconvg.Rasterizer
 	ico.SetDstImage(img, img.Bounds(), draw.Src)
-	m.Palette[0] = f32color.NRGBAToLinearRGBA(ic.Color)
+	m.Palette[0] = f32color.NRGBAToLinearRGBA(color)
 	iconvg.Decode(&ico, ic.src, &iconvg.DecodeOptions{
 		Palette: &m.Palette,
 	})
 	ic.op = paint.NewImageOp(img)
 	ic.imgSize = sz
-	ic.imgColor = ic.Color
+	ic.imgColor = color
 	return ic.op
 }

widget/icon_test.go

@@ -19,14 +19,14 @@ func TestIcon_Alpha(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	icon.Color = color.NRGBA{B: 0xff, A: 0x40}
+	col := color.NRGBA{B: 0xff, A: 0x40}
 
 	gtx := layout.Context{
 		Ops:         new(op.Ops),
 		Constraints: layout.Exact(image.Pt(100, 100)),
 	}
 
-	_ = icon.Layout(gtx)
+	_ = icon.Layout(gtx, col)
 }
 
 // TestWidgetConstraints tests that widgets returns dimensions within their constraints.
@@ -41,7 +41,7 @@ func TestWidgetConstraints(t *testing.T) {
 			label: "Icon",
 			widget: func(gtx layout.Context) layout.Dimensions {
 				ic, _ := NewIcon(icons.ToggleCheckBox)
-				return ic.Layout(gtx)
+				return ic.Layout(gtx, color.NRGBA{A: 0xff})
 			},
 			constraints: _cs(
 				layout.Constraints{

widget/material/button.go

@@ -169,9 +169,8 @@ func (b IconButtonStyle) Layout(gtx layout.Context) layout.Dimensions {
 			return b.Inset.Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 				size := gtx.Px(b.Size)
 				if b.Icon != nil {
-					b.Icon.Color = b.Color
 					gtx.Constraints.Min = image.Point{X: size}
-					b.Icon.Layout(gtx)
+					b.Icon.Layout(gtx, b.Color)
 				}
 				return layout.Dimensions{
 					Size: image.Point{X: size, Y: size},

widget/material/checkable.go

@@ -63,12 +63,12 @@ func (c *checkable) layout(gtx layout.Context, checked, hovered bool) layout.Dim
 				layout.Stacked(func(gtx layout.Context) layout.Dimensions {
 					return layout.UniformInset(unit.Dp(2)).Layout(gtx, func(gtx layout.Context) layout.Dimensions {
 						size := gtx.Px(c.Size)
-						icon.Color = c.IconColor
+						col := c.IconColor
 						if gtx.Queue == nil {
-							icon.Color = f32color.Disabled(icon.Color)
+							col = f32color.Disabled(col)
 						}
 						gtx.Constraints.Min = image.Point{X: size}
-						icon.Layout(gtx)
+						icon.Layout(gtx, col)
 						return layout.Dimensions{
 							Size: image.Point{X: size, Y: size},
 						}