mirror of
https://github.com/golang/go
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90 lines
2.6 KiB
Go
90 lines
2.6 KiB
Go
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package draw
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import (
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"image"
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"testing"
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)
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func eq(c0, c1 image.Color) bool {
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r0, g0, b0, a0 := c0.RGBA()
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r1, g1, b1, a1 := c1.RGBA()
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return r0 == r1 && g0 == g1 && b0 == b1 && a0 == a1
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}
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func fillBlue(alpha int) image.Image {
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return image.ColorImage{image.RGBAColor{0, 0, uint8(alpha), uint8(alpha)}}
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}
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func fillAlpha(alpha int) image.Image {
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return image.ColorImage{image.AlphaColor{uint8(alpha)}}
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}
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func vgradGreen(alpha int) image.Image {
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m := image.NewRGBA(16, 16)
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for y := 0; y < 16; y++ {
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for x := 0; x < 16; x++ {
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m.Set(x, y, image.RGBAColor{0, uint8(y * alpha / 15), 0, uint8(alpha)})
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}
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}
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return m
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}
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func vgradAlpha(alpha int) image.Image {
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m := image.NewAlpha(16, 16)
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for y := 0; y < 16; y++ {
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for x := 0; x < 16; x++ {
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m.Set(x, y, image.AlphaColor{uint8(y * alpha / 15)})
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}
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}
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return m
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}
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func hgradRed(alpha int) Image {
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m := image.NewRGBA(16, 16)
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for y := 0; y < 16; y++ {
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for x := 0; x < 16; x++ {
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m.Set(x, y, image.RGBAColor{uint8(x * alpha / 15), 0, 0, uint8(alpha)})
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}
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}
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return m
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}
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type drawTest struct {
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desc string
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src image.Image
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mask image.Image
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expected image.Color
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}
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var drawTests = []drawTest{
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// Uniform mask (0% opaque) mask.
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drawTest{"nop", vgradGreen(255), fillAlpha(0), image.RGBAColor{136, 0, 0, 255}},
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// Uniform mask (100%, 75%, nil) and vertical-gradient source.
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drawTest{"copy", vgradGreen(90), fillAlpha(255), image.RGBAColor{0, 48, 0, 90}},
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drawTest{"copyAlpha", vgradGreen(90), fillAlpha(192), image.RGBAColor{100, 36, 0, 255}},
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drawTest{"copyNil", vgradGreen(90), nil, image.RGBAColor{0, 48, 0, 90}},
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// Uniform mask (100%, 75%, nil) and uniform source.
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drawTest{"fill", fillBlue(90), fillAlpha(255), image.RGBAColor{0, 0, 90, 90}},
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drawTest{"fillAlpha", fillBlue(90), fillAlpha(192), image.RGBAColor{100, 0, 68, 255}},
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drawTest{"fillNil", fillBlue(90), nil, image.RGBAColor{0, 0, 90, 90}},
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// Variable mask. In detail, at (x, y) == (8, 8):
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// The destination pixel is {136, 0, 0, 255}.
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// The source pixel is {0, 0, 255, 255}.
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// The mask pixel's alpha is 102, or 40%.
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drawTest{"generic", fillBlue(255), vgradAlpha(192), image.RGBAColor{81, 0, 102, 255}},
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}
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func TestDraw(t *testing.T) {
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for _, test := range drawTests {
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dst := hgradRed(255)
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DrawMask(dst, Rect(0, 0, 16, 16), test.src, ZP, test.mask, ZP, SoverD)
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if !eq(dst.At(8, 8), test.expected) {
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t.Errorf("draw %s: %v versus %v", test.desc, dst.At(8, 8), test.expected)
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}
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}
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}
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