gpu,op/clip: encode lines as compute line commands, not quads

The new renderer supports lines natively; encode them as such and
convert them to a quadratic beziér.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/gpu.go

@@ -1393,6 +1393,12 @@ func decodeToOutlineQuads(qs *quadSplitter, tr f32.Affine2D, pathData []byte) {
 		qs.contour = bo.Uint32(pathData)
 		cmd := ops.DecodeCommand(pathData[4:])
 		switch cmd.Op() {
+		case scene.OpFillLine:
+			var q quadSegment
+			q.From, q.To = scene.DecodeLine(cmd)
+			q.Ctrl = q.From.Add(q.To).Mul(.5)
+			q = q.Transform(tr)
+			qs.splitAndEncode(q)
 		case scene.OpFillQuad:
 			var q quadSegment
 			q.From, q.Ctrl, q.To = scene.DecodeQuad(cmd)
@@ -1413,6 +1419,15 @@ func decodeToStrokeQuads(pathData []byte) strokeQuads {
 		contour := bo.Uint32(pathData)
 		cmd := ops.DecodeCommand(pathData[4:])
 		switch cmd.Op() {
+		case scene.OpFillLine:
+			var q quadSegment
+			q.From, q.To = scene.DecodeLine(cmd)
+			q.Ctrl = q.From.Add(q.To).Mul(.5)
+			quad := strokeQuad{
+				contour: contour,
+				quad:    q,
+			}
+			quads = append(quads, quad)
 		case scene.OpFillQuad:
 			var q quadSegment
 			q.From, q.Ctrl, q.To = scene.DecodeQuad(cmd)

op/clip/clip.go

@@ -138,8 +138,12 @@ func (p *Path) Line(delta f32.Point) {
 
 // LineTo moves the pen to the absolute point specified, recording a line.
 func (p *Path) LineTo(to f32.Point) {
-	// Model lines as degenerate quadratic Béziers.
-	p.QuadTo(to.Add(p.pen).Mul(.5), to)
+	data := p.ops.Write(scene.CommandSize + 4)
+	bo := binary.LittleEndian
+	bo.PutUint32(data[0:], uint32(p.contour))
+	ops.EncodeCommand(data[4:], scene.Line(p.pen, to, false, 0))
+	p.pen = to
+	p.hasSegments = true
 }
 
 // Quad records a quadratic Bézier from the pen to end