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) {
 	}
 }
 
+// ColorizeSVG 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 ColorizeSVG(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

@@ -22,19 +22,32 @@ 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 {
+	return colorizeImpl(src, clr, fyne.LogError)
+}
+
+// ColorizeError is the same as Colorize, except returning instead of logging any error.
+func ColorizeError(src []byte, clr color.Color) ([]byte, error) {
+	var err error
+	content := colorizeImpl(src, clr, func(s string, e error) {
+		err = fmt.Errorf("%s %s", s, e.Error())
+	})
+	return content, err
+}
+
+func colorizeImpl(src []byte, clr color.Color, errFn func(string, error)) []byte {
 	rdr := bytes.NewReader(src)
 	s, err := svgFromXML(rdr)
 	if err != nil {
-		fyne.LogError("could not load SVG, falling back to static content:", err)
+		errFn("could not load SVG, falling back to static content:", err)
 		return src
 	}
 	if err := s.replaceFillColor(clr); err != nil {
-		fyne.LogError("could not replace fill color, falling back to static content:", err)
+		errFn("could not replace fill color, falling back to static content:", err)
 		return src
 	}
 	colorized, err := xml.Marshal(s)
 	if err != nil {
-		fyne.LogError("could not marshal svg, falling back to static content:", err)
+		errFn("could not marshal svg, falling back to static content:", err)
 		return src
 	}
 	return colorized