Refactoring refresh code out of theme apply code.

Update some canvas helper functions too - let's not expose internal details

canvas.go

@@ -17,14 +17,11 @@ type Canvas interface {
 	SetOnKeyDown(func(*KeyEvent))
 }
 
-// GetCanvas returns the canvas containing the passed CanvasObject.
-// It will return nil if the CanvasObject has not been added to any Canvas.
-func GetCanvas(obj CanvasObject) Canvas {
+// RefreshObject instructs the containing canvas to refresh the specified obj.
+func RefreshObject(obj CanvasObject) {
 	for _, window := range GetDriver().AllWindows() {
 		if window.Canvas() != nil && window.Canvas().Contains(obj) {
-			return window.Canvas()
+			window.Canvas().Refresh(obj)
 		}
 	}
-
-	return nil
 }

canvas/base.go

@@ -20,7 +20,7 @@ func (r *baseObject) CurrentSize() fyne.Size {
 func (r *baseObject) Resize(size fyne.Size) {
 	r.Size = size
 
-	// TODO refresh?
+	fyne.RefreshObject(r)
 }
 
 // CurrentPosition gets the current position of this rectangle object, relative to it's parent / canvas
@@ -32,17 +32,17 @@ func (r *baseObject) CurrentPosition() fyne.Position {
 func (r *baseObject) Move(pos fyne.Position) {
 	r.Position = pos
 
-	// TODO refresh?
+	fyne.RefreshObject(r)
 }
 
-// MinSize for a Rectangle simply returns Size{1, 1} as there is no
-// explicit content
+// MinSize returns the specified minumum size, if set, or {0, 0} otherwise
 func (r *baseObject) MinSize() fyne.Size {
 	return r.min
 }
 
+// SetMinSize specifies the smallest size this object should be
 func (r *baseObject) SetMinSize(size fyne.Size) {
 	r.min = size
 
-	// TODO refresh?
+	fyne.RefreshObject(r)
 }

canvas_test.go

@@ -1,15 +1,2 @@
 package fyne
 
-import "testing"
-
-import "github.com/stretchr/testify/assert"
-
-// TestGetMissingCanvas checks for the nil case as no canvas was preset.
-// What we want to do is check for the right canvas but we can't call the test
-// package that provides this due to import loops :-/
-func TestGetMissingCanvas(t *testing.T) {
-	box := new(dummyObject)
-
-	setDriver(new(dummyDriver))
-	assert.Equal(t, nil, GetCanvas(box))
-}

examples/apps/life.go

@@ -209,6 +209,10 @@ func (g *gameRenderer) ApplyTheme() {
 	g.deadColor = theme.BackgroundColor()
 }
 
+func (g *gameRenderer) Refresh() {
+	fyne.RefreshObject(g.render)
+}
+
 func (g *gameRenderer) Objects() []fyne.CanvasObject {
 	return g.objects
 }
@@ -259,7 +263,6 @@ func (g *game) toggleRun() {
 func (g *game) animate() {
 	go func() {
 		tick := time.NewTicker(time.Second / 6)
-		canvas := fyne.GetCanvas(g)
 
 		for {
 			select {
@@ -270,7 +273,7 @@ func (g *game) animate() {
 
 				state := g.board.nextGen()
 				g.board.renderState(state)
-				canvas.Refresh(g)
+				g.Renderer().Refresh()
 			}
 		}
 	}()
@@ -291,7 +294,7 @@ func (g *game) OnMouseDown(ev *fyne.MouseEvent) {
 
 	g.board.cells[ypos][xpos] = !g.board.cells[ypos][xpos]
 
-	fyne.GetCanvas(g).Refresh(g)
+	g.Renderer().Refresh()
 }
 
 func newGame(b *board) *game {

widget.go

@@ -6,7 +6,6 @@ package fyne
 type Widget interface {
 	CanvasObject
 
-	// TODO refresh?
 	Renderer() WidgetRenderer
 }
 
@@ -17,6 +16,7 @@ type WidgetRenderer interface {
 	Layout(Size)
 	MinSize() Size
 
+	Refresh()
 	ApplyTheme()
 	Objects() []CanvasObject
 }

widget/button.go

@@ -48,6 +48,12 @@ func (b *buttonRenderer) Layout(size fyne.Size) {
 func (b *buttonRenderer) ApplyTheme() {
 	b.label.Color = theme.TextColor()
 
+	b.Refresh()
+}
+
+func (b *buttonRenderer) Refresh() {
+	b.label.Text = b.button.Text
+
 	if b.button.Style == PrimaryButton {
 		b.background.FillColor = theme.PrimaryColor()
 	} else {
@@ -57,6 +63,8 @@ func (b *buttonRenderer) ApplyTheme() {
 	if b.button.Icon != nil {
 		b.icon.File = b.button.Icon.CachePath()
 	}
+
+	fyne.RefreshObject(b.button)
 }
 
 func (b *buttonRenderer) Objects() []fyne.CanvasObject {

widget/check.go

@@ -42,11 +42,19 @@ func (c *checkRenderer) ApplyTheme() {
 	c.label.Color = theme.TextColor()
 	c.background.FillColor = theme.BackgroundColor()
 
+	c.Refresh()
+}
+
+func (c *checkRenderer) Refresh() {
+	c.label.Text = c.check.Text
+
 	if c.check.Checked {
 		c.icon.File = theme.CheckedIcon().CachePath()
 	} else {
 		c.icon.File = theme.UncheckedIcon().CachePath()
 	}
+
+	fyne.RefreshObject(c.check)
 }
 
 func (c *checkRenderer) Objects() []fyne.CanvasObject {
@@ -65,12 +73,11 @@ type Check struct {
 // OnMouseDown is called when a mouse down event is captured and triggers any change handler
 func (c *Check) OnMouseDown(*fyne.MouseEvent) {
 	c.Checked = !c.Checked
-	c.Renderer().ApplyTheme()
 
 	if c.OnChanged != nil {
 		c.OnChanged(c.Checked)
 	}
-	fyne.GetCanvas(c).Refresh(c)
+	c.Renderer().Refresh()
 }
 
 func (c *Check) createRenderer() fyne.WidgetRenderer {

widget/entry.go

@@ -40,15 +40,21 @@ func (e *entryRenderer) Layout(size fyne.Size) {
 
 // ApplyTheme is called when the Entry may need to update it's look.
 func (e *entryRenderer) ApplyTheme() {
-	e.label.Text = e.entry.Text
 	e.label.Color = theme.TextColor()
+	e.box.FillColor = theme.BackgroundColor()
+	e.Refresh()
+}
+
+func (e *entryRenderer) Refresh() {
+	e.label.Text = e.entry.Text
 
 	if e.entry.focused {
 		e.bg.FillColor = theme.FocusColor()
 	} else {
 		e.bg.FillColor = theme.ButtonColor()
 	}
-	e.box.FillColor = theme.BackgroundColor()
+
+	fyne.RefreshObject(e.entry)
 }
 
 func (e *entryRenderer) Objects() []fyne.CanvasObject {
@@ -73,22 +79,21 @@ func (e *Entry) SetText(text string) {
 		e.OnChanged(text)
 	}
 
-	e.ApplyTheme()
-	fyne.GetCanvas(e).Refresh(e)
+	e.Renderer().Refresh()
 }
 
 // OnFocusGained is called when the Entry has been given focus.
 func (e *Entry) OnFocusGained() {
 	e.focused = true
-	e.ApplyTheme()
-	fyne.GetCanvas(e).Refresh(e)
+
+	e.Renderer().Refresh()
 }
 
 // OnFocusLost is called when the Entry has had focus removed.
 func (e *Entry) OnFocusLost() {
 	e.focused = false
-	e.Renderer().ApplyTheme()
-	fyne.GetCanvas(e).Refresh(e)
+
+	e.Renderer().Refresh()
 }
 
 // Focused returns whether or not this Entry has focus.

widget/label.go

@@ -33,9 +33,14 @@ func (l *labelRenderer) ApplyTheme() {
 	l.background.FillColor = theme.BackgroundColor()
 
 	l.text.Color = theme.TextColor()
+}
+
+func (l *labelRenderer) Refresh() {
 	l.text.Alignment = l.label.Alignment
 	l.text.TextStyle = l.label.TextStyle
 	l.text.Text = l.label.Text
+
+	fyne.RefreshObject(l.label)
 }
 
 // Label widget is a basic text component with appropriate padding and layout.
@@ -50,8 +55,8 @@ type Label struct {
 // SetText updates the text of the label widget
 func (l *Label) SetText(text string) {
 	l.Text = text
-	l.ApplyTheme()
-	fyne.GetCanvas(l).Refresh(l)
+
+	l.Renderer().Refresh()
 }
 
 func (l *Label) createRenderer() fyne.WidgetRenderer {

widget/list.go

@@ -14,20 +14,14 @@ type List struct {
 func (l *List) Prepend(object fyne.CanvasObject) {
 	l.Children = append([]fyne.CanvasObject{object}, l.Children...)
 
-	render := l.Renderer().(*listRenderer)
-	render.objects = l.Children
-	render.Layout(l.CurrentSize())
-
-	fyne.GetCanvas(l).Refresh(l)
+	l.Renderer().Refresh()
 }
 
 // Append adds a new CanvasObject to the end of the list
 func (l *List) Append(object fyne.CanvasObject) {
 	l.Children = append(l.Children, object)
 
-	render := l.Renderer().(*listRenderer)
-
-	render.Refresh()
+	l.Renderer().Refresh()
 }
 
 func (l *List) createRenderer() fyne.WidgetRenderer {
@@ -85,5 +79,5 @@ func (l *listRenderer) Refresh() {
 	l.objects = l.list.Children
 	l.Layout(l.list.CurrentSize())
 
-	fyne.GetCanvas(l.list).Refresh(l.list)
+	fyne.RefreshObject(l.list)
 }