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-rw-r--r--libgo/go/image/names.go67
1 files changed, 67 insertions, 0 deletions
diff --git a/libgo/go/image/names.go b/libgo/go/image/names.go
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+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package image
+
+var (
+ // Black is an opaque black ColorImage.
+ Black = NewColorImage(Gray16Color{0})
+ // White is an opaque white ColorImage.
+ White = NewColorImage(Gray16Color{0xffff})
+ // Transparent is a fully transparent ColorImage.
+ Transparent = NewColorImage(Alpha16Color{0})
+ // Opaque is a fully opaque ColorImage.
+ Opaque = NewColorImage(Alpha16Color{0xffff})
+)
+
+// A ColorImage is an infinite-sized Image of uniform Color.
+// It implements both the Color and Image interfaces.
+type ColorImage struct {
+ C Color
+}
+
+func (c *ColorImage) RGBA() (r, g, b, a uint32) {
+ return c.C.RGBA()
+}
+
+func (c *ColorImage) ColorModel() ColorModel {
+ return ColorModelFunc(func(Color) Color { return c.C })
+}
+
+func (c *ColorImage) Bounds() Rectangle { return Rectangle{Point{-1e9, -1e9}, Point{1e9, 1e9}} }
+
+func (c *ColorImage) At(x, y int) Color { return c.C }
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (c *ColorImage) Opaque() bool {
+ _, _, _, a := c.C.RGBA()
+ return a == 0xffff
+}
+
+func NewColorImage(c Color) *ColorImage {
+ return &ColorImage{c}
+}
+
+// A Tiled is an infinite-sized Image that repeats another Image in both
+// directions. Tiled{i, p}.At(x, y) will equal i.At(x+p.X, y+p.Y) for all
+// points {x+p.X, y+p.Y} within i's Bounds.
+type Tiled struct {
+ I Image
+ Offset Point
+}
+
+func (t *Tiled) ColorModel() ColorModel {
+ return t.I.ColorModel()
+}
+
+func (t *Tiled) Bounds() Rectangle { return Rectangle{Point{-1e9, -1e9}, Point{1e9, 1e9}} }
+
+func (t *Tiled) At(x, y int) Color {
+ p := Point{x, y}.Add(t.Offset).Mod(t.I.Bounds())
+ return t.I.At(p.X, p.Y)
+}
+
+func NewTiled(i Image, offset Point) *Tiled {
+ return &Tiled{i, offset}
+}