116 lines
2.5 KiB
Go
116 lines
2.5 KiB
Go
// Copyright 2011 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 jpeg
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import (
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"bytes"
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"image"
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"image/png"
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"io/ioutil"
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"rand"
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"os"
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"testing"
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)
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var testCase = []struct {
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filename string
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quality int
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tolerance int64
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}{
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{"../testdata/video-001.png", 1, 24 << 8},
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{"../testdata/video-001.png", 20, 12 << 8},
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{"../testdata/video-001.png", 60, 8 << 8},
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{"../testdata/video-001.png", 80, 6 << 8},
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{"../testdata/video-001.png", 90, 4 << 8},
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{"../testdata/video-001.png", 100, 2 << 8},
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}
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func delta(u0, u1 uint32) int64 {
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d := int64(u0) - int64(u1)
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if d < 0 {
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return -d
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}
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return d
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}
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func readPng(filename string) (image.Image, os.Error) {
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f, err := os.Open(filename)
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if err != nil {
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return nil, err
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}
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defer f.Close()
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return png.Decode(f)
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}
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func TestWriter(t *testing.T) {
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for _, tc := range testCase {
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// Read the image.
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m0, err := readPng(tc.filename)
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if err != nil {
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t.Error(tc.filename, err)
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continue
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}
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// Encode that image as JPEG.
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buf := bytes.NewBuffer(nil)
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err = Encode(buf, m0, &Options{Quality: tc.quality})
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if err != nil {
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t.Error(tc.filename, err)
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continue
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}
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// Decode that JPEG.
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m1, err := Decode(buf)
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if err != nil {
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t.Error(tc.filename, err)
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continue
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}
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// Compute the average delta in RGB space.
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b := m0.Bounds()
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var sum, n int64
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for y := b.Min.Y; y < b.Max.Y; y++ {
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for x := b.Min.X; x < b.Max.X; x++ {
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c0 := m0.At(x, y)
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c1 := m1.At(x, y)
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r0, g0, b0, _ := c0.RGBA()
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r1, g1, b1, _ := c1.RGBA()
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sum += delta(r0, r1)
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sum += delta(g0, g1)
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sum += delta(b0, b1)
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n += 3
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}
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}
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// Compare the average delta to the tolerance level.
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if sum/n > tc.tolerance {
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t.Errorf("%s, quality=%d: average delta is too high", tc.filename, tc.quality)
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continue
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}
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}
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}
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func BenchmarkEncodeRGBOpaque(b *testing.B) {
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b.StopTimer()
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img := image.NewRGBA(640, 480)
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// Set all pixels to 0xFF alpha to force opaque mode.
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bo := img.Bounds()
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rnd := rand.New(rand.NewSource(123))
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for y := bo.Min.Y; y < bo.Max.Y; y++ {
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for x := bo.Min.X; x < bo.Max.X; x++ {
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img.Set(x, y, image.RGBAColor{
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uint8(rnd.Intn(256)),
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uint8(rnd.Intn(256)),
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uint8(rnd.Intn(256)),
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255})
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}
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}
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if !img.Opaque() {
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panic("expected image to be opaque")
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}
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b.SetBytes(640 * 480 * 4)
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b.StartTimer()
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options := &Options{Quality: 90}
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for i := 0; i < b.N; i++ {
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Encode(ioutil.Discard, img, options)
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}
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}
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