op/clip: add RoundRect

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

widget/material/material.go

@@ -9,8 +9,6 @@ import (
 	"gioui.org/f32"
 	"gioui.org/font"
 	"gioui.org/layout"
-	"gioui.org/op"
-	"gioui.org/op/clip"
 	"gioui.org/op/paint"
 	"gioui.org/text"
 	"gioui.org/unit"
@@ -75,20 +73,3 @@ func fill(gtx *layout.Context, col color.RGBA) {
 	paint.PaintOp{Rect: dr}.Add(gtx.Ops)
 	gtx.Dimensions = layout.Dimensions{Size: d}
 }
-
-// https://pomax.github.io/bezierinfo/#circles_cubic.
-func rrect(ops *op.Ops, width, height, se, sw, nw, ne float32) {
-	w, h := float32(width), float32(height)
-	const c = 0.55228475 // 4*(sqrt(2)-1)/3
-	var b clip.Path
-	b.Begin(ops)
-	b.Move(f32.Point{X: w, Y: h - se})
-	b.Cube(f32.Point{X: 0, Y: se * c}, f32.Point{X: -se + se*c, Y: se}, f32.Point{X: -se, Y: se}) // SE
-	b.Line(f32.Point{X: sw - w + se, Y: 0})
-	b.Cube(f32.Point{X: -sw * c, Y: 0}, f32.Point{X: -sw, Y: -sw + sw*c}, f32.Point{X: -sw, Y: -sw}) // SW
-	b.Line(f32.Point{X: 0, Y: nw - h + sw})
-	b.Cube(f32.Point{X: 0, Y: -nw * c}, f32.Point{X: nw - nw*c, Y: -nw}, f32.Point{X: nw, Y: -nw}) // NW
-	b.Line(f32.Point{X: w - ne - nw, Y: 0})
-	b.Cube(f32.Point{X: ne * c, Y: 0}, f32.Point{X: ne, Y: ne - ne*c}, f32.Point{X: ne, Y: ne}) // NE
-	b.End().Add(ops)
-}