1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package image 6 7 import ( 8 "image/color" 9 ) 10 11 var ( 12 // Black is an opaque black uniform image. 13 Black = NewUniform(color.Black) 14 // White is an opaque white uniform image. 15 White = NewUniform(color.White) 16 // Transparent is a fully transparent uniform image. 17 Transparent = NewUniform(color.Transparent) 18 // Opaque is a fully opaque uniform image. 19 Opaque = NewUniform(color.Opaque) 20 ) 21 22 // Uniform is an infinite-sized Image of uniform color. 23 // It implements the color.Color, color.Model, and Image interfaces. 24 type Uniform struct { 25 C color.Color 26 } 27 28 func (c *Uniform) RGBA() (r, g, b, a uint32) { 29 return c.C.RGBA() 30 } 31 32 func (c *Uniform) ColorModel() color.Model { 33 return c 34 } 35 36 func (c *Uniform) Convert(color.Color) color.Color { 37 return c.C 38 } 39 40 func (c *Uniform) Bounds() Rectangle { return Rectangle{Point{-1e9, -1e9}, Point{1e9, 1e9}} } 41 42 func (c *Uniform) At(x, y int) color.Color { return c.C } 43 44 // Opaque scans the entire image and reports whether it is fully opaque. 45 func (c *Uniform) Opaque() bool { 46 _, _, _, a := c.C.RGBA() 47 return a == 0xffff 48 } 49 50 func NewUniform(c color.Color) *Uniform { 51 return &Uniform{c} 52 } 53
