// 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 image_test import ( "bufio" "fmt" "image" "image/color" "os" "testing" _ "image/gif" _ "image/jpeg" _ "image/png" ) type imageTest struct { goldenFilename string filename string tolerance int } var imageTests = []imageTest{ {"testdata/video-001.png", "testdata/video-001.png", 0}, // GIF images are restricted to a 256-color palette and the conversion // to GIF loses significant image quality. {"testdata/video-001.png", "testdata/video-001.gif", 64 << 8}, {"testdata/video-001.png", "testdata/video-001.interlaced.gif", 64 << 8}, {"testdata/video-001.png", "testdata/video-001.5bpp.gif", 128 << 8}, // JPEG is a lossy format and hence needs a non-zero tolerance. {"testdata/video-001.png", "testdata/video-001.jpeg", 8 << 8}, {"testdata/video-001.png", "testdata/video-001.progressive.jpeg", 8 << 8}, {"testdata/video-001.221212.png", "testdata/video-001.221212.jpeg", 8 << 8}, {"testdata/video-001.cmyk.png", "testdata/video-001.cmyk.jpeg", 8 << 8}, {"testdata/video-001.rgb.png", "testdata/video-001.rgb.jpeg", 8 << 8}, {"testdata/video-001.progressive.truncated.png", "testdata/video-001.progressive.truncated.jpeg", 8 << 8}, // Grayscale images. {"testdata/video-005.gray.png", "testdata/video-005.gray.jpeg", 8 << 8}, {"testdata/video-005.gray.png", "testdata/video-005.gray.png", 0}, } func decode(filename string) (image.Image, string, error) { f, err := os.Open(filename) if err != nil { return nil, "", err } defer f.Close() return image.Decode(bufio.NewReader(f)) } func decodeConfig(filename string) (image.Config, string, error) { f, err := os.Open(filename) if err != nil { return image.Config{}, "", err } defer f.Close() return image.DecodeConfig(bufio.NewReader(f)) } func delta(u0, u1 uint32) int { d := int(u0) - int(u1) if d < 0 { return -d } return d } func withinTolerance(c0, c1 color.Color, tolerance int) bool { r0, g0, b0, a0 := c0.RGBA() r1, g1, b1, a1 := c1.RGBA() r := delta(r0, r1) g := delta(g0, g1) b := delta(b0, b1) a := delta(a0, a1) return r <= tolerance && g <= tolerance && b <= tolerance && a <= tolerance } func TestDecode(t *testing.T) { rgba := func(c color.Color) string { r, g, b, a := c.RGBA() return fmt.Sprintf("rgba = 0x%04x, 0x%04x, 0x%04x, 0x%04x for %T%v", r, g, b, a, c, c) } golden := make(map[string]image.Image) loop: for _, it := range imageTests { g := golden[it.goldenFilename] if g == nil { var err error g, _, err = decode(it.goldenFilename) if err != nil { t.Errorf("%s: %v", it.goldenFilename, err) continue loop } golden[it.goldenFilename] = g } m, imageFormat, err := decode(it.filename) if err != nil { t.Errorf("%s: %v", it.filename, err) continue loop } b := g.Bounds() if !b.Eq(m.Bounds()) { t.Errorf("%s: got bounds %v want %v", it.filename, m.Bounds(), b) continue loop } for y := b.Min.Y; y < b.Max.Y; y++ { for x := b.Min.X; x < b.Max.X; x++ { if !withinTolerance(g.At(x, y), m.At(x, y), it.tolerance) { t.Errorf("%s: at (%d, %d):\ngot %v\nwant %v", it.filename, x, y, rgba(m.At(x, y)), rgba(g.At(x, y))) continue loop } } } if imageFormat == "gif" { // Each frame of a GIF can have a frame-local palette override the // GIF-global palette. Thus, image.Decode can yield a different ColorModel // than image.DecodeConfig. continue } c, _, err := decodeConfig(it.filename) if err != nil { t.Errorf("%s: %v", it.filename, err) continue loop } if m.ColorModel() != c.ColorModel { t.Errorf("%s: color models differ", it.filename) continue loop } } }