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Side by Side Diff: gfx/codec/jpeg_codec_unittest.cc

Issue 6246027: Move src/gfx/ to src/ui/gfx... (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src/
Patch Set: '' Created 9 years, 10 months ago
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1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include <math.h>
6
7 #include "gfx/codec/jpeg_codec.h"
8 #include "testing/gtest/include/gtest/gtest.h"
9
10 namespace gfx {
11
12 // out of 100, this indicates how compressed it will be, this should be changed
13 // with jpeg equality threshold
14 // static int jpeg_quality = 75; // FIXME(brettw)
15 static int jpeg_quality = 100;
16
17 // The threshold of average color differences where we consider two images
18 // equal. This number was picked to be a little above the observed difference
19 // using the above quality.
20 static double jpeg_equality_threshold = 1.0;
21
22 // Computes the average difference between each value in a and b. A and b
23 // should be the same size. Used to see if two images are approximately equal
24 // in the presence of compression.
25 static double AveragePixelDelta(const std::vector<unsigned char>& a,
26 const std::vector<unsigned char>& b) {
27 // if the sizes are different, say the average difference is the maximum
28 if (a.size() != b.size())
29 return 255.0;
30 if (a.size() == 0)
31 return 0; // prevent divide by 0 below
32
33 double acc = 0.0;
34 for (size_t i = 0; i < a.size(); i++)
35 acc += fabs(static_cast<double>(a[i]) - static_cast<double>(b[i]));
36
37 return acc / static_cast<double>(a.size());
38 }
39
40 static void MakeRGBImage(int w, int h, std::vector<unsigned char>* dat) {
41 dat->resize(w * h * 3);
42 for (int y = 0; y < h; y++) {
43 for (int x = 0; x < w; x++) {
44 unsigned char* org_px = &(*dat)[(y * w + x) * 3];
45 org_px[0] = x * 3; // r
46 org_px[1] = x * 3 + 1; // g
47 org_px[2] = x * 3 + 2; // b
48 }
49 }
50 }
51
52 TEST(JPEGCodec, EncodeDecodeRGB) {
53 int w = 20, h = 20;
54
55 // create an image with known values
56 std::vector<unsigned char> original;
57 MakeRGBImage(w, h, &original);
58
59 // encode, making sure it was compressed some
60 std::vector<unsigned char> encoded;
61 EXPECT_TRUE(JPEGCodec::Encode(&original[0], JPEGCodec::FORMAT_RGB, w, h,
62 w * 3, jpeg_quality, &encoded));
63 EXPECT_GT(original.size(), encoded.size());
64
65 // decode, it should have the same size as the original
66 std::vector<unsigned char> decoded;
67 int outw, outh;
68 EXPECT_TRUE(JPEGCodec::Decode(&encoded[0], encoded.size(),
69 JPEGCodec::FORMAT_RGB, &decoded,
70 &outw, &outh));
71 ASSERT_EQ(w, outw);
72 ASSERT_EQ(h, outh);
73 ASSERT_EQ(original.size(), decoded.size());
74
75 // Images must be approximately equal (compression will have introduced some
76 // minor artifacts).
77 ASSERT_GE(jpeg_equality_threshold, AveragePixelDelta(original, decoded));
78 }
79
80 TEST(JPEGCodec, EncodeDecodeRGBA) {
81 int w = 20, h = 20;
82
83 // create an image with known values, a must be opaque because it will be
84 // lost during compression
85 std::vector<unsigned char> original;
86 original.resize(w * h * 4);
87 for (int y = 0; y < h; y++) {
88 for (int x = 0; x < w; x++) {
89 unsigned char* org_px = &original[(y * w + x) * 4];
90 org_px[0] = x * 3; // r
91 org_px[1] = x * 3 + 1; // g
92 org_px[2] = x * 3 + 2; // b
93 org_px[3] = 0xFF; // a (opaque)
94 }
95 }
96
97 // encode, making sure it was compressed some
98 std::vector<unsigned char> encoded;
99 EXPECT_TRUE(JPEGCodec::Encode(&original[0], JPEGCodec::FORMAT_RGBA, w, h,
100 w * 4, jpeg_quality, &encoded));
101 EXPECT_GT(original.size(), encoded.size());
102
103 // decode, it should have the same size as the original
104 std::vector<unsigned char> decoded;
105 int outw, outh;
106 EXPECT_TRUE(JPEGCodec::Decode(&encoded[0], encoded.size(),
107 JPEGCodec::FORMAT_RGBA, &decoded,
108 &outw, &outh));
109 ASSERT_EQ(w, outw);
110 ASSERT_EQ(h, outh);
111 ASSERT_EQ(original.size(), decoded.size());
112
113 // Images must be approximately equal (compression will have introduced some
114 // minor artifacts).
115 ASSERT_GE(jpeg_equality_threshold, AveragePixelDelta(original, decoded));
116 }
117
118 // Test that corrupted data decompression causes failures.
119 TEST(JPEGCodec, DecodeCorrupted) {
120 int w = 20, h = 20;
121
122 // some random data (an uncompressed image)
123 std::vector<unsigned char> original;
124 MakeRGBImage(w, h, &original);
125
126 // it should fail when given non-JPEG compressed data
127 std::vector<unsigned char> output;
128 int outw, outh;
129 ASSERT_FALSE(JPEGCodec::Decode(&original[0], original.size(),
130 JPEGCodec::FORMAT_RGB, &output,
131 &outw, &outh));
132
133 // make some compressed data
134 std::vector<unsigned char> compressed;
135 ASSERT_TRUE(JPEGCodec::Encode(&original[0], JPEGCodec::FORMAT_RGB, w, h,
136 w * 3, jpeg_quality, &compressed));
137
138 // try decompressing a truncated version
139 ASSERT_FALSE(JPEGCodec::Decode(&compressed[0], compressed.size() / 2,
140 JPEGCodec::FORMAT_RGB, &output,
141 &outw, &outh));
142
143 // corrupt it and try decompressing that
144 for (int i = 10; i < 30; i++)
145 compressed[i] = i;
146 ASSERT_FALSE(JPEGCodec::Decode(&compressed[0], compressed.size(),
147 JPEGCodec::FORMAT_RGB, &output,
148 &outw, &outh));
149 }
150
151 } // namespace gfx
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