Commit fc8e3d40 authored by Nigel Tao's avatar Nigel Tao

exp/draw test.

R=rsc
CC=golang-dev
https://golang.org/cl/203062
parent c27c3aa6
......@@ -121,7 +121,6 @@ DIRS=\
NOTEST=\
debug/proc\
exp/draw\
go/ast\
go/doc\
go/token\
......
// 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 draw
import (
"image"
"testing"
)
func eq(c0, c1 image.Color) bool {
r0, g0, b0, a0 := c0.RGBA()
r1, g1, b1, a1 := c1.RGBA()
return r0 == r1 && g0 == g1 && b0 == b1 && a0 == a1
}
func fillBlue(alpha int) image.Image {
return image.ColorImage{image.RGBAColor{0, 0, uint8(alpha), uint8(alpha)}}
}
func fillAlpha(alpha int) image.Image {
return image.ColorImage{image.AlphaColor{uint8(alpha)}}
}
func vgradGreen(alpha int) image.Image {
m := image.NewRGBA(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.RGBAColor{0, uint8(y * alpha / 15), 0, uint8(alpha)})
}
}
return m
}
func vgradAlpha(alpha int) image.Image {
m := image.NewAlpha(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.AlphaColor{uint8(y * alpha / 15)})
}
}
return m
}
func hgradRed(alpha int) Image {
m := image.NewRGBA(16, 16)
for y := 0; y < 16; y++ {
for x := 0; x < 16; x++ {
m.Set(x, y, image.RGBAColor{uint8(x * alpha / 15), 0, 0, uint8(alpha)})
}
}
return m
}
type drawTest struct {
desc string
src image.Image
mask image.Image
expected image.Color
}
var drawTests = []drawTest{
// Uniform mask (0% opaque) mask.
drawTest{"nop", vgradGreen(255), fillAlpha(0), image.RGBAColor{136, 0, 0, 255}},
// Uniform mask (100%, 75%, nil) and vertical-gradient source.
drawTest{"copy", vgradGreen(90), fillAlpha(255), image.RGBAColor{0, 48, 0, 90}},
drawTest{"copyAlpha", vgradGreen(90), fillAlpha(192), image.RGBAColor{100, 36, 0, 255}},
drawTest{"copyNil", vgradGreen(90), nil, image.RGBAColor{0, 48, 0, 90}},
// Uniform mask (100%, 75%, nil) and uniform source.
drawTest{"fill", fillBlue(90), fillAlpha(255), image.RGBAColor{0, 0, 90, 90}},
drawTest{"fillAlpha", fillBlue(90), fillAlpha(192), image.RGBAColor{100, 0, 68, 255}},
drawTest{"fillNil", fillBlue(90), nil, image.RGBAColor{0, 0, 90, 90}},
// Variable mask. In detail, at (x, y) == (8, 8):
// The destination pixel is {136, 0, 0, 255}.
// The source pixel is {0, 0, 255, 255}.
// The mask pixel's alpha is 102, or 40%.
drawTest{"generic", fillBlue(255), vgradAlpha(192), image.RGBAColor{81, 0, 102, 255}},
}
func TestDraw(t *testing.T) {
for _, test := range drawTests {
dst := hgradRed(255)
DrawMask(dst, Rect(0, 0, 16, 16), test.src, ZP, test.mask, ZP, SoverD)
if !eq(dst.At(8, 8), test.expected) {
t.Errorf("draw %s: %v versus %v", test.desc, dst.At(8, 8), test.expected)
}
}
}
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