libgo/go/image/names.go

   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 }