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Diffstat (limited to 'src/pkg/image/jpeg/writer_test.go')
| -rw-r--r-- | src/pkg/image/jpeg/writer_test.go | 232 |
1 files changed, 0 insertions, 232 deletions
diff --git a/src/pkg/image/jpeg/writer_test.go b/src/pkg/image/jpeg/writer_test.go deleted file mode 100644 index 3df3cfcc5..000000000 --- a/src/pkg/image/jpeg/writer_test.go +++ /dev/null @@ -1,232 +0,0 @@ -// 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" - "fmt" - "image" - "image/color" - "image/png" - "io/ioutil" - "math/rand" - "os" - "testing" -) - -// zigzag maps from the natural ordering to the zig-zag ordering. For example, -// zigzag[0*8 + 3] is the zig-zag sequence number of the element in the fourth -// column and first row. -var zigzag = [blockSize]int{ - 0, 1, 5, 6, 14, 15, 27, 28, - 2, 4, 7, 13, 16, 26, 29, 42, - 3, 8, 12, 17, 25, 30, 41, 43, - 9, 11, 18, 24, 31, 40, 44, 53, - 10, 19, 23, 32, 39, 45, 52, 54, - 20, 22, 33, 38, 46, 51, 55, 60, - 21, 34, 37, 47, 50, 56, 59, 61, - 35, 36, 48, 49, 57, 58, 62, 63, -} - -func TestZigUnzig(t *testing.T) { - for i := 0; i < blockSize; i++ { - if unzig[zigzag[i]] != i { - t.Errorf("unzig[zigzag[%d]] == %d", i, unzig[zigzag[i]]) - } - if zigzag[unzig[i]] != i { - t.Errorf("zigzag[unzig[%d]] == %d", i, zigzag[unzig[i]]) - } - } -} - -// unscaledQuantInNaturalOrder are the unscaled quantization tables in -// natural (not zig-zag) order, as specified in section K.1. -var unscaledQuantInNaturalOrder = [nQuantIndex][blockSize]byte{ - // Luminance. - { - 16, 11, 10, 16, 24, 40, 51, 61, - 12, 12, 14, 19, 26, 58, 60, 55, - 14, 13, 16, 24, 40, 57, 69, 56, - 14, 17, 22, 29, 51, 87, 80, 62, - 18, 22, 37, 56, 68, 109, 103, 77, - 24, 35, 55, 64, 81, 104, 113, 92, - 49, 64, 78, 87, 103, 121, 120, 101, - 72, 92, 95, 98, 112, 100, 103, 99, - }, - // Chrominance. - { - 17, 18, 24, 47, 99, 99, 99, 99, - 18, 21, 26, 66, 99, 99, 99, 99, - 24, 26, 56, 99, 99, 99, 99, 99, - 47, 66, 99, 99, 99, 99, 99, 99, - 99, 99, 99, 99, 99, 99, 99, 99, - 99, 99, 99, 99, 99, 99, 99, 99, - 99, 99, 99, 99, 99, 99, 99, 99, - 99, 99, 99, 99, 99, 99, 99, 99, - }, -} - -func TestUnscaledQuant(t *testing.T) { - bad := false - for i := quantIndex(0); i < nQuantIndex; i++ { - for zig := 0; zig < blockSize; zig++ { - got := unscaledQuant[i][zig] - want := unscaledQuantInNaturalOrder[i][unzig[zig]] - if got != want { - t.Errorf("i=%d, zig=%d: got %d, want %d", i, zig, got, want) - bad = true - } - } - } - if bad { - names := [nQuantIndex]string{"Luminance", "Chrominance"} - buf := &bytes.Buffer{} - for i, name := range names { - fmt.Fprintf(buf, "// %s.\n{\n", name) - for zig := 0; zig < blockSize; zig++ { - fmt.Fprintf(buf, "%d, ", unscaledQuantInNaturalOrder[i][unzig[zig]]) - if zig%8 == 7 { - buf.WriteString("\n") - } - } - buf.WriteString("},\n") - } - t.Logf("expected unscaledQuant values:\n%s", buf.String()) - } -} - -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 - } - 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. - if averageDelta(m0, m1) > tc.tolerance { - t.Errorf("%s, quality=%d: average delta is too high", tc.filename, tc.quality) - continue - } - } -} - -// TestWriteGrayscale tests that a grayscale images survives a round-trip -// through encode/decode cycle. -func TestWriteGrayscale(t *testing.T) { - m0 := image.NewGray(image.Rect(0, 0, 32, 32)) - for i := range m0.Pix { - m0.Pix[i] = uint8(i) - } - var buf bytes.Buffer - if err := Encode(&buf, m0, nil); err != nil { - t.Fatal(err) - } - m1, err := Decode(&buf) - if err != nil { - t.Fatal(err) - } - if m0.Bounds() != m1.Bounds() { - t.Fatalf("bounds differ: %v and %v", m0.Bounds(), m1.Bounds()) - } - if _, ok := m1.(*image.Gray); !ok { - t.Errorf("got %T, want *image.Gray", m1) - } - // Compare the average delta to the tolerance level. - want := int64(2 << 8) - if got := averageDelta(m0, m1); got > want { - t.Errorf("average delta too high; got %d, want <= %d", got, want) - } -} - -// 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 -} - -func BenchmarkEncode(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() - options := &Options{Quality: 90} - for i := 0; i < b.N; i++ { - Encode(ioutil.Discard, img, options) - } -} |