Add a new SimpleRenderer to handle simple cases.

dialog/color_picker.go

@@ -192,7 +192,7 @@ func (p *colorAdvancedPicker) CreateRenderer() fyne.WidgetRenderer {
 	))
 
 	r := &colorPickerRenderer{
-		BaseRenderer:      internalwidget.NewBaseRenderer([]fyne.CanvasObject{contents}),
+		SimpleRenderer:    internalwidget.NewSimpleRenderer(contents),
 		picker:            p,
 		redChannel:        redChannel,
 		greenChannel:      greenChannel,
@@ -253,7 +253,7 @@ func (p *colorAdvancedPicker) updateRGBA(r, g, b, a int) bool {
 var _ fyne.WidgetRenderer = (*colorPickerRenderer)(nil)
 
 type colorPickerRenderer struct {
-	internalwidget.BaseRenderer
+	*internalwidget.SimpleRenderer
 	picker            *colorAdvancedPicker
 	redChannel        *colorChannel
 	greenChannel      *colorChannel
@@ -268,19 +268,9 @@ type colorPickerRenderer struct {
 	contents          fyne.CanvasObject
 }
 
-func (r *colorPickerRenderer) Layout(size fyne.Size) {
-	r.contents.Move(fyne.NewPos(0, 0))
-	r.contents.Resize(size)
-}
-
-func (r *colorPickerRenderer) MinSize() fyne.Size {
-	return r.contents.MinSize()
-}
-
 func (r *colorPickerRenderer) Refresh() {
 	r.updateObjects()
-	r.Layout(r.picker.Size())
-	canvas.Refresh(r.picker)
+	r.SimpleRenderer.Refresh()
 }
 
 func (r *colorPickerRenderer) updateObjects() {

internal/app/focus_manager_test.go

@@ -151,12 +151,12 @@ var _ fyne.Disableable = (*focusable)(nil)
 
 type focusable struct {
 	widget.DisableableWidget
-	children []fyne.CanvasObject
-	focused  bool
+	child   fyne.CanvasObject
+	focused bool
 }
 
 func (f *focusable) CreateRenderer() fyne.WidgetRenderer {
-	return &focusableRenderer{BaseRenderer: internalWidget.NewBaseRenderer(f.children)}
+	return internalWidget.NewSimpleRenderer(f.child)
 }
 
 func (f *focusable) FocusGained() {
@@ -176,27 +176,11 @@ func (f *focusable) TypedRune(_ rune) {
 func (f *focusable) TypedKey(_ *fyne.KeyEvent) {
 }
 
-var _ fyne.WidgetRenderer = (*focusableRenderer)(nil)
-
-type focusableRenderer struct {
-	internalWidget.BaseRenderer
-}
-
-func (f focusableRenderer) Layout(_ fyne.Size) {
-}
-
-func (f focusableRenderer) MinSize() fyne.Size {
-	return fyne.NewSize(0, 0)
-}
-
-func (f focusableRenderer) Refresh() {
-}
-
 func setupFocusManager(t *testing.T) (m *app.FocusManager, entry1, hidden, visibleInsideHidden, entry2, disabled, entry3 *focusable) {
 	entry1 = &focusable{}
 	visibleInsideHidden = &focusable{}
 	hidden = &focusable{
-		children: []fyne.CanvasObject{visibleInsideHidden},
+		child: visibleInsideHidden,
 	}
 	hidden.Hide()
 	entry2 = &focusable{}

internal/widget/simple_renderer.go

@@ -0,0 +1,65 @@
+package widget
+
+import "fyne.io/fyne/v2"
+
+var _ fyne.WidgetRenderer = (*SimpleRenderer)(nil)
+
+// SimpleRenderer is a basic renderer that satisfies widget.Renderer interface by wrapping
+// a single fyne.CanvasObject.
+//
+// Since: 2.1
+type SimpleRenderer struct {
+	objects []fyne.CanvasObject
+}
+
+// NewSimpleRenderer creates a new SimpleRenderer to render a widget using a
+// single CanvasObject.
+//
+// Since: 2.1
+func NewSimpleRenderer(object fyne.CanvasObject) *SimpleRenderer {
+	return &SimpleRenderer{[]fyne.CanvasObject{object}}
+}
+
+// Destroy does nothing in this implementation.
+//
+// Implements: fyne.WidgetRenderer
+//
+// Since: 2.1
+func (r *SimpleRenderer) Destroy() {
+}
+
+// Layout updates the contained object to be the requested size.
+//
+// Implements: fyne.WidgetRenderer
+//
+// Since: 2.1
+func (r *SimpleRenderer) Layout(s fyne.Size) {
+	r.objects[0].Resize(s)
+}
+
+// MinSize returns the smallest size that this render can use, returned from the underlying object.
+//
+// Implements: fyne.WidgetRenderer
+//
+// Since: 2.1
+func (r *SimpleRenderer) MinSize() fyne.Size {
+	return r.objects[0].MinSize()
+}
+
+// Objects returns the objects that should be rendered.
+//
+// Implements: fyne.WidgetRenderer
+//
+// Since: 2.1
+func (r *SimpleRenderer) Objects() []fyne.CanvasObject {
+	return r.objects
+}
+
+// Refresh requests the underlying object to redraw.
+//
+// Implements: fyne.WidgetRenderer
+//
+// Since: 2.1
+func (r *SimpleRenderer) Refresh() {
+	r.objects[0].Refresh()
+}

internal/widget/simple_renderer_test.go

@@ -0,0 +1,30 @@
+package widget_test
+
+import (
+	"image/color"
+	"testing"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/internal/widget"
+	"fyne.io/fyne/v2/test"
+)
+
+func TestNewSimpleRenderer(t *testing.T) {
+	r := canvas.NewRectangle(color.Transparent)
+	o := &simpleWidget{obj: r}
+	o.ExtendBaseWidget(o)
+	w := test.NewWindow(o)
+	w.Resize(fyne.NewSize(100, 100))
+
+	test.AssertRendersToMarkup(t, "simple_renderer.xml", w.Canvas())
+}
+
+type simpleWidget struct {
+	widget.Base
+	obj fyne.CanvasObject
+}
+
+func (s *simpleWidget) CreateRenderer() fyne.WidgetRenderer {
+	return widget.NewSimpleRenderer(s.obj)
+}

internal/widget/testdata/simple_renderer.xml

@@ -0,0 +1,7 @@
+<canvas padded size="100x100">
+	<content>
+		<widget pos="4,4" size="92x92" type="*widget_test.simpleWidget">
+			<rectangle size="92x92"/>
+		</widget>
+	</content>
+</canvas>

widget/entry_password.go

@@ -1,12 +1,9 @@
 package widget
 
 import (
-	"image/color"
-
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
 	"fyne.io/fyne/v2/driver/desktop"
-	"fyne.io/fyne/v2/internal/widget"
 	"fyne.io/fyne/v2/theme"
 )
 
@@ -32,9 +29,9 @@ func newPasswordRevealer(e *Entry) *passwordRevealer {
 
 func (r *passwordRevealer) CreateRenderer() fyne.WidgetRenderer {
 	return &passwordRevealerRenderer{
-		BaseRenderer: widget.NewBaseRenderer([]fyne.CanvasObject{r.icon}),
-		icon:         r.icon,
-		entry:        r.entry,
+		WidgetRenderer: NewSimpleRenderer(r.icon),
+		icon:           r.icon,
+		entry:          r.entry,
 	}
 }
 
@@ -52,15 +49,11 @@ func (r *passwordRevealer) Tapped(*fyne.PointEvent) {
 var _ fyne.WidgetRenderer = (*passwordRevealerRenderer)(nil)
 
 type passwordRevealerRenderer struct {
-	widget.BaseRenderer
+	fyne.WidgetRenderer
 	entry *Entry
 	icon  *canvas.Image
 }
 
-func (r *passwordRevealerRenderer) BackgroundColor() color.Color {
-	return color.Transparent
-}
-
 func (r *passwordRevealerRenderer) Layout(size fyne.Size) {
 	r.icon.Resize(fyne.NewSize(theme.IconInlineSize(), theme.IconInlineSize()))
 	r.icon.Move(fyne.NewPos((size.Width-theme.IconInlineSize())/2, (size.Height-theme.IconInlineSize())/2))

widget/entry_validation.go

@@ -3,7 +3,6 @@ package widget
 import (
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
-	"fyne.io/fyne/v2/internal/widget"
 	"fyne.io/fyne/v2/theme"
 )
 
@@ -69,16 +68,16 @@ func (r *validationStatus) CreateRenderer() fyne.WidgetRenderer {
 	icon := &canvas.Image{}
 	icon.Hide()
 	return &validationStatusRenderer{
-		BaseRenderer: widget.NewBaseRenderer([]fyne.CanvasObject{icon}),
-		icon:         icon,
-		entry:        r.entry,
+		WidgetRenderer: NewSimpleRenderer(icon),
+		icon:           icon,
+		entry:          r.entry,
 	}
 }
 
 var _ fyne.WidgetRenderer = (*validationStatusRenderer)(nil)
 
 type validationStatusRenderer struct {
-	widget.BaseRenderer
+	fyne.WidgetRenderer
 	entry *Entry
 	icon  *canvas.Image
 }

widget/form.go

@@ -6,6 +6,7 @@ import (
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
 	"fyne.io/fyne/v2/internal/cache"
+	internalWidget "fyne.io/fyne/v2/internal/widget"
 	"fyne.io/fyne/v2/layout"
 	"fyne.io/fyne/v2/theme"
 )
@@ -261,7 +262,7 @@ func (f *Form) CreateRenderer() fyne.WidgetRenderer {
 	}
 	f.itemGrid = fyne.NewContainerWithLayout(layout.NewFormLayout(), objects...)
 
-	renderer := &simpleRenderer{content: fyne.NewContainerWithLayout(layout.NewVBoxLayout(), f.itemGrid, f.buttonBox)}
+	renderer := internalWidget.NewSimpleRenderer(fyne.NewContainerWithLayout(layout.NewVBoxLayout(), f.itemGrid, f.buttonBox))
 	f.updateButtons()      // will set correct visibility on the submit/cancel btns
 	f.checkValidation(nil) // will trigger a validation check for correct initial validation status
 	return renderer

widget/separator.go

@@ -3,7 +3,6 @@ package widget
 import (
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
-	"fyne.io/fyne/v2/internal/widget"
 	"fyne.io/fyne/v2/theme"
 )
 
@@ -31,11 +30,10 @@ func NewSeparator() *Separator {
 func (s *Separator) CreateRenderer() fyne.WidgetRenderer {
 	s.ExtendBaseWidget(s)
 	bar := canvas.NewRectangle(theme.DisabledColor())
-	objects := []fyne.CanvasObject{bar}
 	return &separatorRenderer{
-		BaseRenderer: widget.NewBaseRenderer(objects),
-		bar:          bar,
-		d:            s,
+		WidgetRenderer: NewSimpleRenderer(bar),
+		bar:            bar,
+		d:              s,
 	}
 }
 
@@ -51,15 +49,11 @@ func (s *Separator) MinSize() fyne.Size {
 var _ fyne.WidgetRenderer = (*separatorRenderer)(nil)
 
 type separatorRenderer struct {
-	widget.BaseRenderer
+	fyne.WidgetRenderer
 	bar *canvas.Rectangle
 	d   *Separator
 }
 
-func (r *separatorRenderer) Layout(size fyne.Size) {
-	r.bar.Resize(size)
-}
-
 func (r *separatorRenderer) MinSize() fyne.Size {
 	t := theme.SeparatorThicknessSize()
 	return fyne.NewSize(t, t)

widget/widget.go

@@ -7,6 +7,7 @@ import (
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/canvas"
 	"fyne.io/fyne/v2/internal/cache"
+	internalWidget "fyne.io/fyne/v2/internal/widget"
 )
 
 // BaseWidget provides a helper that handles basic widget behaviours.
@@ -198,25 +199,10 @@ func (w *DisableableWidget) Disabled() bool {
 	return w.disabled
 }
 
-type simpleRenderer struct {
-	content *fyne.Container
-}
-
-func (s *simpleRenderer) Destroy() {
-}
-
-func (s *simpleRenderer) Layout(size fyne.Size) {
-	s.content.Resize(size)
-}
-
-func (s *simpleRenderer) MinSize() fyne.Size {
-	return s.content.MinSize()
-}
-
-func (s *simpleRenderer) Objects() []fyne.CanvasObject {
-	return []fyne.CanvasObject{s.content}
-}
-
-func (s *simpleRenderer) Refresh() {
-	s.content.Refresh()
+// NewSimpleRenderer creates a new SimpleRenderer to render a widget using a
+// single fyne.CanvasObject.
+//
+// Since: 2.1
+func NewSimpleRenderer(object fyne.CanvasObject) fyne.WidgetRenderer {
+	return internalWidget.NewSimpleRenderer(object)
 }