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// Copyright 2013 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 gif
import (
"bytes"
"image"
"image/color"
_ "image/png"
"io/ioutil"
"math/rand"
"os"
"testing"
)
func readImg(filename string) (image.Image, error) {
f, err := os.Open(filename)
if err != nil {
return nil, err
}
defer f.Close()
m, _, err := image.Decode(f)
return m, err
}
func readGIF(filename string) (*GIF, error) {
f, err := os.Open(filename)
if err != nil {
return nil, err
}
defer f.Close()
return DecodeAll(f)
}
func delta(u0, u1 uint32) int64 {
d := int64(u0) - int64(u1)
if d < 0 {
return -d
}
return d
}
// averageDelta returns the average delta in RGB space. The two images must
// have the same bounds.
func averageDelta(m0, m1 image.Image) int64 {
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
}
}
return sum / n
}
var testCase = []struct {
filename string
tolerance int64
}{
{"../testdata/video-001.png", 1 << 12},
{"../testdata/video-001.gif", 0},
{"../testdata/video-001.interlaced.gif", 0},
}
func TestWriter(t *testing.T) {
for _, tc := range testCase {
m0, err := readImg(tc.filename)
if err != nil {
t.Error(tc.filename, err)
continue
}
var buf bytes.Buffer
err = Encode(&buf, m0, nil)
if err != nil {
t.Error(tc.filename, err)
continue
}
m1, err := Decode(&buf)
if err != nil {
t.Error(tc.filename, err)
continue
}
if m0.Bounds() != m1.Bounds() {
t.Errorf("%s, bounds differ: %v and %v", tc.filename, m0.Bounds(), m1.Bounds())
continue
}
// Compare the average delta to the tolerance level.
avgDelta := averageDelta(m0, m1)
if avgDelta > tc.tolerance {
t.Errorf("%s: average delta is too high. expected: %d, got %d", tc.filename, tc.tolerance, avgDelta)
continue
}
}
}
func TestSubImage(t *testing.T) {
m0, err := readImg("../testdata/video-001.gif")
if err != nil {
t.Fatalf("readImg: %v", err)
}
m0 = m0.(*image.Paletted).SubImage(image.Rect(0, 0, 50, 30))
var buf bytes.Buffer
err = Encode(&buf, m0, nil)
if err != nil {
t.Fatalf("Encode: %v", err)
}
m1, err := Decode(&buf)
if err != nil {
t.Fatalf("Decode: %v", err)
}
if m0.Bounds() != m1.Bounds() {
t.Fatalf("bounds differ: %v and %v", m0.Bounds(), m1.Bounds())
}
if averageDelta(m0, m1) != 0 {
t.Fatalf("images differ")
}
}
var frames = []string{
"../testdata/video-001.gif",
"../testdata/video-005.gray.gif",
}
func TestEncodeAll(t *testing.T) {
g0 := &GIF{
Image: make([]*image.Paletted, len(frames)),
Delay: make([]int, len(frames)),
LoopCount: 5,
}
for i, f := range frames {
m, err := readGIF(f)
if err != nil {
t.Fatal(f, err)
}
g0.Image[i] = m.Image[0]
}
var buf bytes.Buffer
if err := EncodeAll(&buf, g0); err != nil {
t.Fatal("EncodeAll:", err)
}
g1, err := DecodeAll(&buf)
if err != nil {
t.Fatal("DecodeAll:", err)
}
if g0.LoopCount != g1.LoopCount {
t.Errorf("loop counts differ: %d and %d", g0.LoopCount, g1.LoopCount)
}
for i := range g0.Image {
m0, m1 := g0.Image[i], g1.Image[i]
if m0.Bounds() != m1.Bounds() {
t.Errorf("%s, bounds differ: %v and %v", frames[i], m0.Bounds(), m1.Bounds())
}
d0, d1 := g0.Delay[i], g1.Delay[i]
if d0 != d1 {
t.Errorf("%s: delay values differ: %d and %d", frames[i], d0, d1)
}
}
g1.Delay = make([]int, 1)
if err := EncodeAll(ioutil.Discard, g1); err == nil {
t.Error("expected error from mismatched delay and image slice lengths")
}
if err := EncodeAll(ioutil.Discard, &GIF{}); err == nil {
t.Error("expected error from providing empty gif")
}
}
func BenchmarkEncode(b *testing.B) {
b.StopTimer()
bo := image.Rect(0, 0, 640, 480)
rnd := rand.New(rand.NewSource(123))
// Restrict to a 256-color paletted image to avoid quantization path.
palette := make(color.Palette, 256)
for i := range palette {
palette[i] = color.RGBA{
uint8(rnd.Intn(256)),
uint8(rnd.Intn(256)),
uint8(rnd.Intn(256)),
255,
}
}
img := image.NewPaletted(image.Rect(0, 0, 640, 480), palette)
for y := bo.Min.Y; y < bo.Max.Y; y++ {
for x := bo.Min.X; x < bo.Max.X; x++ {
img.Set(x, y, palette[rnd.Intn(256)])
}
}
b.SetBytes(640 * 480 * 4)
b.StartTimer()
for i := 0; i < b.N; i++ {
Encode(ioutil.Discard, img, nil)
}
}
func BenchmarkQuantizedEncode(b *testing.B) {
b.StopTimer()
img := image.NewRGBA(image.Rect(0, 0, 640, 480))
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.SetRGBA(x, y, color.RGBA{
uint8(rnd.Intn(256)),
uint8(rnd.Intn(256)),
uint8(rnd.Intn(256)),
255,
})
}
}
b.SetBytes(640 * 480 * 4)
b.StartTimer()
for i := 0; i < b.N; i++ {
Encode(ioutil.Discard, img, nil)
}
}
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