Optimize radio item renderer to be 50% faster

goos: linux
goarch: amd64
pkg: fyne.io/fyne/v2/widget
cpu: Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz
                      │   old.txt   │               new.txt               │
                      │   sec/op    │   sec/op     vs base                │
RadioCreateRenderer-8   664.0n ± 2%   351.4n ± 2%  -47.09% (p=0.000 n=10)

                      │  old.txt   │              new.txt              │
                      │    B/op    │    B/op     vs base               │
RadioCreateRenderer-8   736.0 ± 0%   704.0 ± 0%  -4.35% (p=0.000 n=10)

                      │  old.txt   │              new.txt               │
                      │ allocs/op  │ allocs/op   vs base                │
RadioCreateRenderer-8   9.000 ± 0%   4.000 ± 0%  -55.56% (p=0.000 n=10)

widget/radio_item.go

@@ -37,19 +37,8 @@ type radioItem struct {
 //
 // Implements: fyne.Widget
 func (i *radioItem) CreateRenderer() fyne.WidgetRenderer {
-	focusIndicator := canvas.NewCircle(color.Transparent)
-	icon := canvas.NewImageFromResource(theme.RadioButtonFillIcon())
-	over := canvas.NewImageFromResource(theme.NewThemedResource(theme.RadioButtonIcon()))
-	label := canvas.NewText(i.Label, theme.ForegroundColor())
-	label.Alignment = fyne.TextAlignLeading
-	r := &radioItemRenderer{
-		BaseRenderer:   widget.NewBaseRenderer([]fyne.CanvasObject{focusIndicator, icon, over, label}),
-		focusIndicator: focusIndicator,
-		icon:           icon,
-		over:           over,
-		item:           i,
-		label:          label,
-	}
+	r := &radioItemRenderer{item: i, label: canvas.Text{Alignment: fyne.TextAlignLeading}}
+	r.SetObjects([]fyne.CanvasObject{&r.focusIndicator, &r.icon, &r.over, &r.label})
 	r.update()
 	return r
 }
@@ -149,11 +138,11 @@ func (i *radioItem) toggle() {
 
 type radioItemRenderer struct {
 	widget.BaseRenderer
+	item *radioItem
 
-	focusIndicator *canvas.Circle
-	icon, over     *canvas.Image
-	item           *radioItem
-	label          *canvas.Text
+	focusIndicator canvas.Circle
+	icon, over     canvas.Image
+	label          canvas.Text
 }
 
 func (r *radioItemRenderer) Layout(size fyne.Size) {
@@ -191,10 +180,11 @@ func (r *radioItemRenderer) Refresh() {
 
 func (r *radioItemRenderer) update() {
 	r.label.Text = r.item.Label
-	r.label.Color = theme.ForegroundColor()
 	r.label.TextSize = theme.TextSize()
 	if r.item.Disabled() {
 		r.label.Color = theme.DisabledColor()
+	} else {
+		r.label.Color = theme.ForegroundColor()
 	}
 
 	out := theme.NewThemedResource(theme.RadioButtonIcon())

widget/radio_item_test.go

@@ -10,6 +10,21 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var globalRadioRenderer fyne.WidgetRenderer
+
+func BenchmarkRadioCreateRenderer(b *testing.B) {
+	var renderer fyne.WidgetRenderer
+	widget := &radioItem{}
+	b.ReportAllocs()
+
+	for i := 0; i < b.N; i++ {
+		renderer = widget.CreateRenderer()
+	}
+
+	// Avoid having the value optimized out by the compiler.
+	globalRadioRenderer = renderer
+}
+
 func TestRadioItem_FocusIndicator_Centered_Vertically(t *testing.T) {
 	item := newRadioItem("Hello", nil)
 	render := test.WidgetRenderer(item).(*radioItemRenderer)