diff options
Diffstat (limited to 'vendor/gioui.org/op/clip/shapes.go')
| -rw-r--r-- | vendor/gioui.org/op/clip/shapes.go | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/vendor/gioui.org/op/clip/shapes.go b/vendor/gioui.org/op/clip/shapes.go new file mode 100644 index 0000000..30609e5 --- /dev/null +++ b/vendor/gioui.org/op/clip/shapes.go @@ -0,0 +1,185 @@ +// SPDX-License-Identifier: Unlicense OR MIT + +package clip + +import ( + "image" + "math" + + "gioui.org/f32" + "gioui.org/internal/ops" + "gioui.org/op" +) + +// Rect represents the clip area of a pixel-aligned rectangle. +type Rect image.Rectangle + +// Op returns the op for the rectangle. +func (r Rect) Op() Op { + return Op{ + outline: true, + path: r.Path(), + } +} + +// Push the clip operation on the clip stack. +func (r Rect) Push(ops *op.Ops) Stack { + return r.Op().Push(ops) +} + +// Path returns the PathSpec for the rectangle. +func (r Rect) Path() PathSpec { + return PathSpec{ + shape: ops.Rect, + bounds: image.Rectangle(r), + } +} + +// UniformRRect returns an RRect with all corner radii set to the +// provided radius. +func UniformRRect(rect f32.Rectangle, radius float32) RRect { + return RRect{ + Rect: rect, + SE: radius, + SW: radius, + NE: radius, + NW: radius, + } +} + +// RRect represents the clip area of a rectangle with rounded +// corners. +// +// Specify a square with corner radii equal to half the square size to +// construct a circular clip area. +type RRect struct { + Rect f32.Rectangle + // The corner radii. + SE, SW, NW, NE float32 +} + +// Op returns the op for the rounded rectangle. +func (rr RRect) Op(ops *op.Ops) Op { + if rr.SE == 0 && rr.SW == 0 && rr.NW == 0 && rr.NE == 0 { + r := image.Rectangle{ + Min: image.Point{X: int(rr.Rect.Min.X), Y: int(rr.Rect.Min.Y)}, + Max: image.Point{X: int(rr.Rect.Max.X), Y: int(rr.Rect.Max.Y)}, + } + // Only use Rect if rr is pixel-aligned, as Rect is guaranteed to be. + if fPt(r.Min) == rr.Rect.Min && fPt(r.Max) == rr.Rect.Max { + return Rect(r).Op() + } + } + return Outline{Path: rr.Path(ops)}.Op() +} + +// Push the rectangle clip on the clip stack. +func (rr RRect) Push(ops *op.Ops) Stack { + return rr.Op(ops).Push(ops) +} + +// Path returns the PathSpec for the rounded rectangle. +func (rr RRect) Path(ops *op.Ops) PathSpec { + var p Path + p.Begin(ops) + + // https://pomax.github.io/bezierinfo/#circles_cubic. + const q = 4 * (math.Sqrt2 - 1) / 3 + const iq = 1 - q + + se, sw, nw, ne := rr.SE, rr.SW, rr.NW, rr.NE + w, n, e, s := rr.Rect.Min.X, rr.Rect.Min.Y, rr.Rect.Max.X, rr.Rect.Max.Y + + p.MoveTo(f32.Point{X: w + nw, Y: n}) + p.LineTo(f32.Point{X: e - ne, Y: n}) // N + p.CubeTo( // NE + f32.Point{X: e - ne*iq, Y: n}, + f32.Point{X: e, Y: n + ne*iq}, + f32.Point{X: e, Y: n + ne}) + p.LineTo(f32.Point{X: e, Y: s - se}) // E + p.CubeTo( // SE + f32.Point{X: e, Y: s - se*iq}, + f32.Point{X: e - se*iq, Y: s}, + f32.Point{X: e - se, Y: s}) + p.LineTo(f32.Point{X: w + sw, Y: s}) // S + p.CubeTo( // SW + f32.Point{X: w + sw*iq, Y: s}, + f32.Point{X: w, Y: s - sw*iq}, + f32.Point{X: w, Y: s - sw}) + p.LineTo(f32.Point{X: w, Y: n + nw}) // W + p.CubeTo( // NW + f32.Point{X: w, Y: n + nw*iq}, + f32.Point{X: w + nw*iq, Y: n}, + f32.Point{X: w + nw, Y: n}) + + return p.End() +} + +// Ellipse represents the largest axis-aligned ellipse that +// is contained in its bounds. +type Ellipse f32.Rectangle + +// Op returns the op for the filled ellipse. +func (e Ellipse) Op(ops *op.Ops) Op { + return Outline{Path: e.Path(ops)}.Op() +} + +// Push the filled ellipse clip op on the clip stack. +func (e Ellipse) Push(ops *op.Ops) Stack { + return e.Op(ops).Push(ops) +} + +// Path constructs a path for the ellipse. +func (e Ellipse) Path(o *op.Ops) PathSpec { + bounds := f32.Rectangle(e) + if bounds.Dx() == 0 || bounds.Dy() == 0 { + return PathSpec{shape: ops.Rect} + } + + var p Path + p.Begin(o) + + center := bounds.Max.Add(bounds.Min).Mul(.5) + diam := bounds.Dx() + r := diam * .5 + // We'll model the ellipse as a circle scaled in the Y + // direction. + scale := bounds.Dy() / diam + + // https://pomax.github.io/bezierinfo/#circles_cubic. + const q = 4 * (math.Sqrt2 - 1) / 3 + + curve := r * q + top := f32.Point{X: center.X, Y: center.Y - r*scale} + + p.MoveTo(top) + p.CubeTo( + f32.Point{X: center.X + curve, Y: center.Y - r*scale}, + f32.Point{X: center.X + r, Y: center.Y - curve*scale}, + f32.Point{X: center.X + r, Y: center.Y}, + ) + p.CubeTo( + f32.Point{X: center.X + r, Y: center.Y + curve*scale}, + f32.Point{X: center.X + curve, Y: center.Y + r*scale}, + f32.Point{X: center.X, Y: center.Y + r*scale}, + ) + p.CubeTo( + f32.Point{X: center.X - curve, Y: center.Y + r*scale}, + f32.Point{X: center.X - r, Y: center.Y + curve*scale}, + f32.Point{X: center.X - r, Y: center.Y}, + ) + p.CubeTo( + f32.Point{X: center.X - r, Y: center.Y - curve*scale}, + f32.Point{X: center.X - curve, Y: center.Y - r*scale}, + top, + ) + ellipse := p.End() + ellipse.shape = ops.Ellipse + return ellipse +} + +func fPt(p image.Point) f32.Point { + return f32.Point{ + X: float32(p.X), Y: float32(p.Y), + } +} |