op/clip: expose Circle.Path and RRect.Path.

These can be nicely used together with clip.Stroke.

Signed-off-by: Egon Elbre <egonelbre@gmail.com>

widget/border.go

@@ -7,7 +7,6 @@ import (
 
 	"gioui.org/f32"
 	"gioui.org/layout"
-	"gioui.org/op"
 	"gioui.org/op/clip"
 	"gioui.org/op/paint"
 	"gioui.org/unit"
@@ -23,24 +22,20 @@ type Border struct {
 func (b Border) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions {
 	dims := w(gtx)
 	sz := dims.Size
+
 	rr := float32(gtx.Px(b.CornerRadius))
-	st := op.Save(gtx.Ops)
-	width := gtx.Px(b.Width)
-	sz.X -= width
-	sz.Y -= width
-	op.Offset(f32.Point{
-		X: float32(width) * 0.5,
-		Y: float32(width) * 0.5,
-	}).Add(gtx.Ops)
-	clip.Border{
-		Rect: f32.Rectangle{
-			Max: layout.FPt(sz),
-		},
-		NE: rr, NW: rr, SE: rr, SW: rr,
-		Width: float32(width),
-	}.Add(gtx.Ops)
-	paint.ColorOp{Color: b.Color}.Add(gtx.Ops)
-	paint.PaintOp{}.Add(gtx.Ops)
-	st.Load()
+	width := float32(gtx.Px(b.Width))
+
+	r := f32.Rectangle{Max: layout.FPt(sz)}
+	r = r.Add(f32.Point{X: width * 0.5, Y: width * 0.5})
+
+	paint.FillShape(gtx.Ops,
+		b.Color,
+		clip.Stroke{
+			Path:  clip.UniformRRect(r, rr).Path(gtx.Ops),
+			Style: clip.StrokeStyle{Width: width},
+		}.Op(),
+	)
+
 	return dims
 }