Source file src/pkg/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.ColorModel, 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 returns whether or not 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	}