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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [image/] [jpeg/] [writer_test.go] - Blame information for rev 747

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1 747 jeremybenn 
// 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/color"
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        "image/png"
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        "io/ioutil"
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        "math/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, 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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                var buf bytes.Buffer
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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(image.Rect(0, 0, 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, color.RGBA{
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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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                b.Fatal("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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