Subversion Repositories openrisc

// Copyright 2011 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 jpeg

import (
        "bytes"
        "image"
        "image/color"
        "image/png"
        "io/ioutil"
        "math/rand"
        "os"
        "testing"
)

var testCase = []struct {
        filename  string
        quality   int
        tolerance int64
}{
        {"../testdata/video-001.png", 1, 24 << 8},
        {"../testdata/video-001.png", 20, 12 << 8},
        {"../testdata/video-001.png", 60, 8 << 8},
        {"../testdata/video-001.png", 80, 6 << 8},
        {"../testdata/video-001.png", 90, 4 << 8},
        {"../testdata/video-001.png", 100, 2 << 8},
}

func delta(u0, u1 uint32) int64 {
        d := int64(u0) - int64(u1)
        if d < 0 {
                return -d
        }
        return d
}

func readPng(filename string) (image.Image, error) {
        f, err := os.Open(filename)
        if err != nil {
                return nil, err
        }
        defer f.Close()
        return png.Decode(f)
}

func TestWriter(t *testing.T) {
        for _, tc := range testCase {
                // Read the image.
                m0, err := readPng(tc.filename)
                if err != nil {
                        t.Error(tc.filename, err)
                        continue
                }
                // Encode that image as JPEG.
                var buf bytes.Buffer
                err = Encode(&buf, m0, &Options{Quality: tc.quality})
                if err != nil {
                        t.Error(tc.filename, err)
                        continue
                }
                // Decode that JPEG.
                m1, err := Decode(&buf)
                if err != nil {
                        t.Error(tc.filename, err)
                        continue
                }
                // Compute the average delta in RGB space.
                b := m0.Bounds()
                var sum, n int64
                for y := b.Min.Y; y < b.Max.Y; y++ {
                        for x := b.Min.X; x < b.Max.X; x++ {
                                c0 := m0.At(x, y)
                                c1 := m1.At(x, y)
                                r0, g0, b0, _ := c0.RGBA()
                                r1, g1, b1, _ := c1.RGBA()
                                sum += delta(r0, r1)
                                sum += delta(g0, g1)
                                sum += delta(b0, b1)
                                n += 3
                        }
                }
                // Compare the average delta to the tolerance level.
                if sum/n > tc.tolerance {
                        t.Errorf("%s, quality=%d: average delta is too high", tc.filename, tc.quality)
                        continue
                }
        }
}

func BenchmarkEncodeRGBOpaque(b *testing.B) {
        b.StopTimer()
        img := image.NewRGBA(image.Rect(0, 0, 640, 480))
        // Set all pixels to 0xFF alpha to force opaque mode.
        bo := img.Bounds()
        rnd := rand.New(rand.NewSource(123))
        for y := bo.Min.Y; y < bo.Max.Y; y++ {
                for x := bo.Min.X; x < bo.Max.X; x++ {
                        img.Set(x, y, color.RGBA{
                                uint8(rnd.Intn(256)),
                                uint8(rnd.Intn(256)),
                                uint8(rnd.Intn(256)),
                                255})
                }
        }
        if !img.Opaque() {
                b.Fatal("expected image to be opaque")
        }
        b.SetBytes(640 * 480 * 4)
        b.StartTimer()
        options := &Options{Quality: 90}
        for i := 0; i < b.N; i++ {
                Encode(ioutil.Discard, img, options)
        }
}