Merge pull request #5315 from andydotxyz/fix/5313

Handle the negative offsets in viewport that Google started using

internal/svg/svg.go

@@ -80,7 +80,8 @@ func (d *Decoder) Draw(width, height int) (*image.NRGBA, error) {
 		imgH = int(float32(width) / config.Aspect)
 	}
 
-	d.icon.SetTarget(0, 0, float64(imgW), float64(imgH))
+	x, y := svgOffset(d.icon, imgW, imgH)
+	d.icon.SetTarget(x, y, float64(imgW), float64(imgH))
 
 	img := image.NewNRGBA(image.Rect(0, 0, imgW, imgH))
 	scanner := rasterx.NewScannerGV(config.Width, config.Height, img, img.Bounds())
@@ -115,6 +116,14 @@ func IsResourceSVG(res fyne.Resource) bool {
 	return false
 }
 
+func svgOffset(icon *oksvg.SvgIcon, _, height int) (x, y float64) {
+	if icon.ViewBox.Y < 0 { // adjust so our positive offset calculations work
+		y = icon.ViewBox.Y + (-icon.ViewBox.Y/icon.ViewBox.H)*float64(height)
+	}
+
+	return 0, y
+}
+
 // svg holds the unmarshaled XML from a Scalable Vector Graphic
 type svg struct {
 	XMLName  xml.Name      `xml:"svg"`

internal/svg/svg_test.go

@@ -44,6 +44,11 @@ func TestColorize(t *testing.T) {
 			color:     color.NRGBA{R: 100, G: 100, B: 100, A: 200},
 			wantImage: "colorized/rects.png",
 		},
+		"negative rects": {
+			svgFile:   "rects-negative.svg",
+			color:     color.NRGBA{R: 100, G: 100, B: 100, A: 200},
+			wantImage: "colorized/rects.png",
+		},
 		"group of paths": {
 			svgFile:   "check_GroupPaths.svg",
 			color:     color.NRGBA{R: 100, G: 100, A: 100},
@@ -195,7 +200,8 @@ func helperDrawSVG(t *testing.T, data []byte) image.Image {
 
 	width := int(icon.ViewBox.W) * 2
 	height := int(icon.ViewBox.H) * 2
-	icon.SetTarget(0, 0, float64(width), float64(height))
+	x, y := svgOffset(icon, width, height)
+	icon.SetTarget(x, y, float64(width), float64(height))
 	img := image.NewNRGBA(image.Rect(0, 0, width, height))
 	scanner := rasterx.NewScannerGV(width, height, img, img.Bounds())
 	raster := rasterx.NewDasher(width, height, scanner)