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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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