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 fyne.Resource containing SVG content, and returns
+// the raw 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 content of the input Resource,
+// and a non-nil error is returned.
+//
+// Since: 2.6
+func RecolorSVG(resource fyne.Resource, color color.Color) ([]byte, error) {
+	return svg.ColorizeError(resource.Content(), color)
+}
+
 // repaint instructs the containing canvas to redraw, even if nothing changed.
 func repaint(obj fyne.CanvasObject) {
 	app := fyne.CurrentApp()

internal/svg/svg.go

@@ -22,22 +22,28 @@ 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 {
+	content, err := ColorizeError(src, clr)
+	if err != nil {
+		fyne.LogError("", err)
+	}
+	return content
+}
+
+// ColorizeError is the same as Colorize, except returning instead of logging any error.
+func ColorizeError(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 {