text: render SVG font as black-white outline

Previously, using SVG fonts will cause Gio to render invisible
"characters".

Now, some fonts (like Noto Sans Emoji) will be rendered
based on "Outline". Gio don't support SVG fonts, but now
it will show the outline ("black-and-white") alternative.

Signed-off-by: Lucas Rodrigues <inkeliz@inkeliz.com>

text/gotext.go

@@ -656,12 +656,20 @@ func (s *shaperImpl) Shape(pathOps *op.Ops, gs []Glyph) clip.PathSpec {
 		}
 		scaleFactor := fixedToFloat(ppem) / float32(face.Upem())
 		glyphData := face.GlyphData(gid)
+
+		var outline font.GlyphOutline
 		switch glyphData := glyphData.(type) {
 		case font.GlyphOutline:
-			outline := glyphData
+			outline = glyphData
+		case font.GlyphSVG:
+			outline = glyphData.Outline
+		default:
+			continue
+		}
+
 		// Move to glyph position.
 		pos := f32.Point{
-				X: fixedToFloat((g.X - x) + g.Offset.X),
+			X: fixedToFloat((g.X - x) - g.Offset.X),
 			Y: -fixedToFloat(g.Offset.Y),
 		}
 		builder.Move(pos.Sub(lastPos))
@@ -703,7 +711,6 @@ func (s *shaperImpl) Shape(pathOps *op.Ops, gs []Glyph) clip.PathSpec {
 		}
 		lastPos = lastPos.Add(lastArg)
 	}
-	}
 	return builder.End()
 }