1// Copyright 2011 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package image_test
6
7import (
8	"bufio"
9	"fmt"
10	"image"
11	"image/color"
12	"os"
13	"testing"
14
15	_ "image/gif"
16	_ "image/jpeg"
17	_ "image/png"
18)
19
20type imageTest struct {
21	goldenFilename string
22	filename       string
23	tolerance      int
24}
25
26var imageTests = []imageTest{
27	{"testdata/video-001.png", "testdata/video-001.png", 0},
28	// GIF images are restricted to a 256-color palette and the conversion
29	// to GIF loses significant image quality.
30	{"testdata/video-001.png", "testdata/video-001.gif", 64 << 8},
31	{"testdata/video-001.png", "testdata/video-001.interlaced.gif", 64 << 8},
32	{"testdata/video-001.png", "testdata/video-001.5bpp.gif", 128 << 8},
33	// JPEG is a lossy format and hence needs a non-zero tolerance.
34	{"testdata/video-001.png", "testdata/video-001.jpeg", 8 << 8},
35	{"testdata/video-001.png", "testdata/video-001.progressive.jpeg", 8 << 8},
36	{"testdata/video-001.221212.png", "testdata/video-001.221212.jpeg", 8 << 8},
37	{"testdata/video-001.cmyk.png", "testdata/video-001.cmyk.jpeg", 8 << 8},
38	{"testdata/video-001.rgb.png", "testdata/video-001.rgb.jpeg", 8 << 8},
39	{"testdata/video-001.progressive.truncated.png", "testdata/video-001.progressive.truncated.jpeg", 8 << 8},
40	// Grayscale images.
41	{"testdata/video-005.gray.png", "testdata/video-005.gray.jpeg", 8 << 8},
42	{"testdata/video-005.gray.png", "testdata/video-005.gray.png", 0},
43}
44
45func decode(filename string) (image.Image, string, error) {
46	f, err := os.Open(filename)
47	if err != nil {
48		return nil, "", err
49	}
50	defer f.Close()
51	return image.Decode(bufio.NewReader(f))
52}
53
54func decodeConfig(filename string) (image.Config, string, error) {
55	f, err := os.Open(filename)
56	if err != nil {
57		return image.Config{}, "", err
58	}
59	defer f.Close()
60	return image.DecodeConfig(bufio.NewReader(f))
61}
62
63func delta(u0, u1 uint32) int {
64	d := int(u0) - int(u1)
65	if d < 0 {
66		return -d
67	}
68	return d
69}
70
71func withinTolerance(c0, c1 color.Color, tolerance int) bool {
72	r0, g0, b0, a0 := c0.RGBA()
73	r1, g1, b1, a1 := c1.RGBA()
74	r := delta(r0, r1)
75	g := delta(g0, g1)
76	b := delta(b0, b1)
77	a := delta(a0, a1)
78	return r <= tolerance && g <= tolerance && b <= tolerance && a <= tolerance
79}
80
81func TestDecode(t *testing.T) {
82	rgba := func(c color.Color) string {
83		r, g, b, a := c.RGBA()
84		return fmt.Sprintf("rgba = 0x%04x, 0x%04x, 0x%04x, 0x%04x for %T%v", r, g, b, a, c, c)
85	}
86
87	golden := make(map[string]image.Image)
88loop:
89	for _, it := range imageTests {
90		g := golden[it.goldenFilename]
91		if g == nil {
92			var err error
93			g, _, err = decode(it.goldenFilename)
94			if err != nil {
95				t.Errorf("%s: %v", it.goldenFilename, err)
96				continue loop
97			}
98			golden[it.goldenFilename] = g
99		}
100		m, imageFormat, err := decode(it.filename)
101		if err != nil {
102			t.Errorf("%s: %v", it.filename, err)
103			continue loop
104		}
105		b := g.Bounds()
106		if !b.Eq(m.Bounds()) {
107			t.Errorf("%s: got bounds %v want %v", it.filename, m.Bounds(), b)
108			continue loop
109		}
110		for y := b.Min.Y; y < b.Max.Y; y++ {
111			for x := b.Min.X; x < b.Max.X; x++ {
112				if !withinTolerance(g.At(x, y), m.At(x, y), it.tolerance) {
113					t.Errorf("%s: at (%d, %d):\ngot  %v\nwant %v",
114						it.filename, x, y, rgba(m.At(x, y)), rgba(g.At(x, y)))
115					continue loop
116				}
117			}
118		}
119		if imageFormat == "gif" {
120			// Each frame of a GIF can have a frame-local palette override the
121			// GIF-global palette. Thus, image.Decode can yield a different ColorModel
122			// than image.DecodeConfig.
123			continue
124		}
125		c, _, err := decodeConfig(it.filename)
126		if m.ColorModel() != c.ColorModel {
127			t.Errorf("%s: color models differ", it.filename)
128			continue loop
129		}
130	}
131}
132