Add new canvas.RecolorSVG API

canvas/canvas.go

@@ -1,6 +1,11 @@
 package canvas
 
-import "fyne.io/fyne/v2"
+import (
+	"image/color"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/internal/svg"
+)
 
 // Refresh instructs the containing canvas to refresh the specified obj.
 func Refresh(obj fyne.CanvasObject) {
@@ -15,6 +20,19 @@ func Refresh(obj fyne.CanvasObject) {
 	}
 }
 
+// RecolorSVG takes a []byte containing SVG content, and returns
+// new SVG content, re-colorized to be monochrome with the given color.
+// The content can be assigned to a new fyne.StaticResource with an appropriate name
+// to be used in a widget.Button, canvas.Image, etc.
+//
+// If an error occurs, the returned content will be the original un-modified content,
+// and a non-nil error is returned.
+//
+// Since: 2.6
+func RecolorSVG(svgContent []byte, color color.Color) ([]byte, error) {
+	return svg.Colorize(svgContent, color)
+}
+
 // repaint instructs the containing canvas to redraw, even if nothing changed.
 func repaint(obj fyne.CanvasObject) {
 	app := fyne.CurrentApp()

canvas/image.go

@@ -279,7 +279,11 @@ func (i *Image) updateReader() (io.ReadCloser, error) {
 			th := cache.WidgetTheme(i)
 			if th != nil {
 				col := th.Color(res.ThemeColorName(), fyne.CurrentApp().Settings().ThemeVariant())
-				content = svg.Colorize(content, col)
+				var err error
+				content, err = svg.Colorize(content, col)
+				if err != nil {
+					fyne.LogError("", err)
+				}
 			}
 		}
 		return io.NopCloser(bytes.NewReader(content)), nil

internal/driver/glfw/menu_darwin.go

@@ -179,9 +179,13 @@ func insertNativeMenuItem(nsMenu unsafe.Pointer, item *fyne.MenuItem, nextItemID
 			if _, isThemed := rsc.(*theme.ThemedResource); isThemed {
 				var r, g, b, a C.int
 				C.getTextColorRGBA(&r, &g, &b, &a)
+				content, err := svg.Colorize(rsc.Content(), color.NRGBA{R: uint8(r), G: uint8(g), B: uint8(b), A: uint8(a)})
+				if err != nil {
+					fyne.LogError("", err)
+				}
 				rsc = &fyne.StaticResource{
 					StaticName:    rsc.Name(),
-					StaticContent: svg.Colorize(rsc.Content(), color.NRGBA{R: uint8(r), G: uint8(g), B: uint8(b), A: uint8(a)}),
+					StaticContent: content,
 				}
 			}
 			size := int(C.menuFontSize())

internal/svg/svg.go

@@ -21,23 +21,20 @@ import (
 )
 
 // Colorize creates a new SVG from a given one by replacing all fill colors by the given color.
-func Colorize(src []byte, clr color.Color) []byte {
+func Colorize(src []byte, clr color.Color) ([]byte, error) {
 	rdr := bytes.NewReader(src)
 	s, err := svgFromXML(rdr)
 	if err != nil {
-		fyne.LogError("could not load SVG, falling back to static content:", err)
-		return src
+		return src, fmt.Errorf("could not load SVG, falling back to static content: %v", err)
 	}
 	if err := s.replaceFillColor(clr); err != nil {
-		fyne.LogError("could not replace fill color, falling back to static content:", err)
-		return src
+		return src, fmt.Errorf("could not replace fill color, falling back to static content: %v", err)
 	}
 	colorized, err := xml.Marshal(s)
 	if err != nil {
-		fyne.LogError("could not marshal svg, falling back to static content:", err)
-		return src
+		return src, fmt.Errorf("could not marshal svg, falling back to static content: %v", err)
 	}
-	return colorized
+	return colorized, nil
 }
 
 type Decoder struct {

internal/svg/svg_test.go

@@ -144,7 +144,8 @@ func TestColorize(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			bytes, err := os.ReadFile(filepath.Join("testdata", tt.svgFile))
 			require.NoError(t, err)
-			got := helperDrawSVG(t, Colorize(bytes, tt.color))
+			content, _ := Colorize(bytes, tt.color)
+			got := helperDrawSVG(t, content)
 			test.AssertImageMatches(t, tt.wantImage, got)
 		})
 	}

theme/icons.go

@@ -1,6 +1,8 @@
 package theme
 
 import (
+	"image/color"
+
 	"fyne.io/fyne/v2"
 	"fyne.io/fyne/v2/internal/svg"
 )
@@ -712,7 +714,7 @@ func (res *ThemedResource) ThemeColorName() fyne.ThemeColorName {
 
 // Content returns the underlying content of the resource adapted to the current text color.
 func (res *ThemedResource) Content() []byte {
-	return svg.Colorize(unwrapResource(res.source).Content(), Color(res.ThemeColorName()))
+	return colorizeLogError(unwrapResource(res.source).Content(), Color(res.ThemeColorName()))
 }
 
 // Error returns a different resource for indicating an error.
@@ -742,7 +744,7 @@ func (res *InvertedThemedResource) Name() string {
 // Content returns the underlying content of the resource adapted to the current background color.
 func (res *InvertedThemedResource) Content() []byte {
 	clr := Color(ColorNameBackground)
-	return svg.Colorize(unwrapResource(res.source).Content(), clr)
+	return colorizeLogError(unwrapResource(res.source).Content(), clr)
 }
 
 // ThemeColorName returns the fyne.ThemeColorName that is used as foreground color.
@@ -775,7 +777,7 @@ func (res *ErrorThemedResource) Name() string {
 
 // Content returns the underlying content of the resource adapted to the current background color.
 func (res *ErrorThemedResource) Content() []byte {
-	return svg.Colorize(unwrapResource(res.source).Content(), Color(ColorNameError))
+	return colorizeLogError(unwrapResource(res.source).Content(), Color(ColorNameError))
 }
 
 // Original returns the underlying resource that this error themed resource was adapted from
@@ -810,7 +812,7 @@ func (res *PrimaryThemedResource) Name() string {
 
 // Content returns the underlying content of the resource adapted to the current background color.
 func (res *PrimaryThemedResource) Content() []byte {
-	return svg.Colorize(unwrapResource(res.source).Content(), Color(ColorNamePrimary))
+	return colorizeLogError(unwrapResource(res.source).Content(), Color(ColorNamePrimary))
 }
 
 // Original returns the underlying resource that this primary themed resource was adapted from
@@ -839,7 +841,7 @@ func (res *DisabledResource) Name() string {
 
 // Content returns the disabled style content of the correct resource for the current theme
 func (res *DisabledResource) Content() []byte {
-	return svg.Colorize(unwrapResource(res.source).Content(), Color(ColorNameDisabled))
+	return colorizeLogError(unwrapResource(res.source).Content(), Color(ColorNameDisabled))
 }
 
 // ThemeColorName returns the fyne.ThemeColorName that is used as foreground color.
@@ -1399,3 +1401,11 @@ func unwrapResource(res fyne.Resource) fyne.Resource {
 		}
 	}
 }
+
+func colorizeLogError(src []byte, clr color.Color) []byte {
+	content, err := svg.Colorize(src, clr)
+	if err != nil {
+		fyne.LogError("", err)
+	}
+	return content
+}