text,widget,opentype: change text.Face.Shape to return a clip.PathSpec

With this change, the Shape function returns a clip.PathSpec
instead of a clip.Outline op. It is then possible to create
a clip.Outline or clip.Stroke op to fill the text path or
draw its stroke.

Signed-off-by: Christophe Meessen <meessen@cppm.in2p3.fr>

font/opentype/opentype.go

@@ -119,7 +119,7 @@ func (f *Font) Layout(ppem fixed.Int26_6, maxWidth int, txt io.Reader) ([]text.L
 	return layoutText(&buf, ppem, maxWidth, fonts, glyphs)
 }
 
-func (f *Font) Shape(ppem fixed.Int26_6, str text.Layout) clip.Op {
+func (f *Font) Shape(ppem fixed.Int26_6, str text.Layout) clip.PathSpec {
 	var buf sfnt.Buffer
 	return textPath(&buf, ppem, []*opentype{{Font: f.font, Hinting: font.HintingFull}}, str)
 }
@@ -139,7 +139,7 @@ func (c *Collection) Layout(ppem fixed.Int26_6, maxWidth int, txt io.Reader) ([]
 	return layoutText(&buf, ppem, maxWidth, c.fonts, glyphs)
 }
 
-func (c *Collection) Shape(ppem fixed.Int26_6, str text.Layout) clip.Op {
+func (c *Collection) Shape(ppem fixed.Int26_6, str text.Layout) clip.PathSpec {
 	var buf sfnt.Buffer
 	return textPath(&buf, ppem, c.fonts, str)
 }
@@ -261,12 +261,11 @@ func toLayout(glyphs []glyph) text.Layout {
 	return text.Layout{Text: buf.String(), Advances: advs}
 }
 
-func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, fonts []*opentype, str text.Layout) clip.Op {
+func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, fonts []*opentype, str text.Layout) clip.PathSpec {
 	var lastPos f32.Point
 	var builder clip.Path
-	ops := new(op.Ops)
 	var x fixed.Int26_6
-	builder.Begin(ops)
+	builder.Begin(new(op.Ops))
 	rune := 0
 	for _, r := range str.Text {
 		if !unicode.IsSpace(r) {
@@ -323,9 +322,7 @@ func textPath(buf *sfnt.Buffer, ppem fixed.Int26_6, fonts []*opentype, str text.
 		x += str.Advances[rune]
 		rune++
 	}
-	return clip.Outline{
+	return builder.End()
-		Path: builder.End(),
-	}.Op()
 }
 
 func readGlyphs(r io.Reader) ([]glyph, error) {

font/opentype/opentype_test.go

@@ -70,7 +70,7 @@ func TestCollectionAsFace(t *testing.T) {
 
 	// All shapes from the original fonts should be distinct because the glyphs are distinct, including the replacement
 	// glyphs.
-	distinctShapes := []clip.Op{shapeValid1, shapeInvalid1, shapeValid2, shapeInvalid2}
+	distinctShapes := []clip.PathSpec{shapeValid1, shapeInvalid1, shapeValid2, shapeInvalid2}
 	for i := 0; i < len(distinctShapes); i++ {
 		for j := i + 1; j < len(distinctShapes); j++ {
 			if areShapesEqual(distinctShapes[i], distinctShapes[j]) {
@@ -174,23 +174,23 @@ func mergeFonts(ttf1, ttf2 []byte) []byte {
 }
 
 // shapeRune uses a given Face to shape exactly one rune at a fixed size, then returns the resulting shape data.
-func shapeRune(f text.Face, r rune) (clip.Op, error) {
+func shapeRune(f text.Face, r rune) (clip.PathSpec, error) {
 	ppem := fixed.I(200)
 	lines, err := f.Layout(ppem, 2000, strings.NewReader(string(r)))
 	if err != nil {
-		return clip.Op{}, err
+		return clip.PathSpec{}, err
 	}
 	if len(lines) != 1 {
-		return clip.Op{}, fmt.Errorf("unexpected rendering for \"U+%08X\": got %d lines (expected: 1)", r, len(lines))
+		return clip.PathSpec{}, fmt.Errorf("unexpected rendering for \"U+%08X\": got %d lines (expected: 1)", r, len(lines))
 	}
 	return f.Shape(ppem, lines[0].Layout), nil
 }
 
 // areShapesEqual returns true iff both given text shapes are produced with identical operations.
-func areShapesEqual(shape1, shape2 clip.Op) bool {
+func areShapesEqual(shape1, shape2 clip.PathSpec) bool {
 	var ops1, ops2 op.Ops
-	shape1.Push(&ops1).Pop()
+	clip.Outline{Path: shape1}.Op().Push(&ops1).Pop()
-	shape2.Push(&ops2).Pop()
+	clip.Outline{Path: shape2}.Op().Push(&ops2).Pop()
 	var r1, r2 ops.Reader
 	r1.Reset(&ops1.Internal)
 	r2.Reset(&ops2.Internal)

text/lru.go

@@ -26,7 +26,7 @@ type layoutElem struct {
 type path struct {
 	next, prev *path
 	key        pathKey
-	val        clip.Op
+	val        clip.PathSpec
 }
 
 type layoutKey struct {
@@ -81,16 +81,16 @@ func (l *layoutCache) insert(lt *layoutElem) {
 	lt.next.prev = lt
 }
 
-func (c *pathCache) Get(k pathKey) (clip.Op, bool) {
+func (c *pathCache) Get(k pathKey) (clip.PathSpec, bool) {
 	if v, ok := c.m[k]; ok {
 		c.remove(v)
 		c.insert(v)
 		return v.val, true
 	}
-	return clip.Op{}, false
+	return clip.PathSpec{}, false
 }
 
-func (c *pathCache) Put(k pathKey, v clip.Op) {
+func (c *pathCache) Put(k pathKey, v clip.PathSpec) {
 	if c.m == nil {
 		c.m = make(map[pathKey]*path)
 		c.head = new(path)

text/lru_test.go

@@ -24,7 +24,7 @@ func TestLayoutLRU(t *testing.T) {
 func TestPathLRU(t *testing.T) {
 	c := new(pathCache)
 	put := func(i int) {
-		c.Put(pathKey{str: strconv.Itoa(i)}, clip.Op{})
+		c.Put(pathKey{str: strconv.Itoa(i)}, clip.PathSpec{})
 	}
 	get := func(i int) bool {
 		_, ok := c.Get(pathKey{str: strconv.Itoa(i)})

text/shaper.go

@@ -18,7 +18,7 @@ type Shaper interface {
 	// LayoutString is Layout for strings.
 	LayoutString(font Font, size fixed.Int26_6, maxWidth int, str string) []Line
 	// Shape a line of text and return a clipping operation for its outline.
-	Shape(font Font, size fixed.Int26_6, layout Layout) clip.Op
+	Shape(font Font, size fixed.Int26_6, layout Layout) clip.PathSpec
 }
 
 // A FontFace is a Font and a matching Face.
@@ -121,7 +121,7 @@ func (c *Cache) LayoutString(font Font, size fixed.Int26_6, maxWidth int, str st
 
 // Shape is a caching implementation of the Shaper interface. Shape assumes that the layout
 // argument is unchanged from a call to Layout or LayoutString.
-func (c *Cache) Shape(font Font, size fixed.Int26_6, layout Layout) clip.Op {
+func (c *Cache) Shape(font Font, size fixed.Int26_6, layout Layout) clip.PathSpec {
 	cache := c.lookup(font)
 	return cache.shape(size, layout)
 }
@@ -143,9 +143,9 @@ func (f *faceCache) layout(ppem fixed.Int26_6, maxWidth int, str string) []Line
 	return l
 }
 
-func (f *faceCache) shape(ppem fixed.Int26_6, layout Layout) clip.Op {
+func (f *faceCache) shape(ppem fixed.Int26_6, layout Layout) clip.PathSpec {
 	if f == nil {
-		return clip.Op{}
+		return clip.PathSpec{}
 	}
 	pk := pathKey{
 		ppem: ppem,

text/text.go

@@ -48,7 +48,7 @@ type Font struct {
 // methods must be safe for concurrent use.
 type Face interface {
 	Layout(ppem fixed.Int26_6, maxWidth int, txt io.Reader) ([]Line, error)
-	Shape(ppem fixed.Int26_6, str Layout) clip.Op
+	Shape(ppem fixed.Int26_6, str Layout) clip.PathSpec
 }
 
 // Typeface identifies a particular typeface design. The empty

widget/editor.go

@@ -531,8 +531,8 @@ func (e *Editor) layout(gtx layout.Context, content layout.Widget) layout.Dimens
 		if !ok {
 			break
 		}
-		path := e.shaper.Shape(e.font, e.textSize, layout)
+		op := clip.Outline{Path: e.shaper.Shape(e.font, e.textSize, layout)}.Op()
-		e.shapes = append(e.shapes, line{off, path, selected, yOffs, size})
+		e.shapes = append(e.shapes, line{off, op, selected, yOffs, size})
 	}
 
 	key.InputOp{Tag: &e.eventKey, Hint: e.InputHint}.Add(gtx.Ops)

widget/label.go

@@ -179,7 +179,7 @@ func (l Label) Layout(gtx layout.Context, s text.Shaper, font text.Font, size un
 		}
 		t := op.Offset(layout.FPt(off)).Push(gtx.Ops)
 		rcl := clip.Rect(cl.Sub(off)).Push(gtx.Ops)
-		cl := s.Shape(font, textSize, l).Push(gtx.Ops)
+		cl := clip.Outline{Path: s.Shape(font, textSize, l)}.Op().Push(gtx.Ops)
 		paint.PaintOp{}.Add(gtx.Ops)
 		cl.Pop()
 		rcl.Pop()