1*c8dee2aaSAndroid Build Coastguard Worker // Copyright 2019 Google LLC.
2*c8dee2aaSAndroid Build Coastguard Worker // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3*c8dee2aaSAndroid Build Coastguard Worker
4*c8dee2aaSAndroid Build Coastguard Worker // Image Diff: Provides a metric for measuring the difference between two encoded images. Prints
5*c8dee2aaSAndroid Build Coastguard Worker // out a single floating-point number between 0.0 and 1.0; 0 means that the images are identical; 1
6*c8dee2aaSAndroid Build Coastguard Worker // means that each pixel is maximally different in each channel. A non-zero return value indicates
7*c8dee2aaSAndroid Build Coastguard Worker // that something went wrong.
8*c8dee2aaSAndroid Build Coastguard Worker
9*c8dee2aaSAndroid Build Coastguard Worker #include "include/codec/SkCodec.h"
10*c8dee2aaSAndroid Build Coastguard Worker #include "include/core/SkBitmap.h"
11*c8dee2aaSAndroid Build Coastguard Worker #include "include/core/SkData.h"
12*c8dee2aaSAndroid Build Coastguard Worker #include "include/core/SkPixmap.h"
13*c8dee2aaSAndroid Build Coastguard Worker #include "include/core/SkSize.h"
14*c8dee2aaSAndroid Build Coastguard Worker
15*c8dee2aaSAndroid Build Coastguard Worker #include <cmath>
16*c8dee2aaSAndroid Build Coastguard Worker #include <cstdio>
17*c8dee2aaSAndroid Build Coastguard Worker
main(int argc,char ** argv)18*c8dee2aaSAndroid Build Coastguard Worker int main(int argc, char** argv) {
19*c8dee2aaSAndroid Build Coastguard Worker if (argc != 3) {
20*c8dee2aaSAndroid Build Coastguard Worker const char usage[] = "\nUsage:\n %s {FILE1}.png {FILE2}.png\n\n";
21*c8dee2aaSAndroid Build Coastguard Worker fprintf(stderr, usage, argv[0]);
22*c8dee2aaSAndroid Build Coastguard Worker return 1;
23*c8dee2aaSAndroid Build Coastguard Worker }
24*c8dee2aaSAndroid Build Coastguard Worker SkBitmap bm[2];
25*c8dee2aaSAndroid Build Coastguard Worker for (int i = 0; i < 2; ++i) {
26*c8dee2aaSAndroid Build Coastguard Worker const char* path = argv[i + 1];
27*c8dee2aaSAndroid Build Coastguard Worker if (std::unique_ptr<SkCodec> codec =
28*c8dee2aaSAndroid Build Coastguard Worker SkCodec::MakeFromData(SkData::MakeFromFileName(path))) {
29*c8dee2aaSAndroid Build Coastguard Worker bm[i].allocN32Pixels(codec->dimensions().fWidth, codec->dimensions().fHeight);
30*c8dee2aaSAndroid Build Coastguard Worker if (SkCodec::kSuccess == codec->getPixels(bm[i].pixmap())) {
31*c8dee2aaSAndroid Build Coastguard Worker continue;
32*c8dee2aaSAndroid Build Coastguard Worker }
33*c8dee2aaSAndroid Build Coastguard Worker }
34*c8dee2aaSAndroid Build Coastguard Worker fprintf(stderr, "\nBad file: '%s'.\n\n", path);
35*c8dee2aaSAndroid Build Coastguard Worker return 2;
36*c8dee2aaSAndroid Build Coastguard Worker }
37*c8dee2aaSAndroid Build Coastguard Worker SkISize dim = bm[0].dimensions();
38*c8dee2aaSAndroid Build Coastguard Worker if (dim != bm[1].dimensions()) {
39*c8dee2aaSAndroid Build Coastguard Worker fprintf(stderr, "\nImages must be same size: (%d,%d) != (%d,%d)\n\n",
40*c8dee2aaSAndroid Build Coastguard Worker dim.fWidth, dim.fHeight, bm[1].dimensions().fWidth, bm[1].dimensions().fHeight);
41*c8dee2aaSAndroid Build Coastguard Worker return 3;
42*c8dee2aaSAndroid Build Coastguard Worker }
43*c8dee2aaSAndroid Build Coastguard Worker int64_t totalDiffs = 0; // Manhattan distance in ARGB color-space.
44*c8dee2aaSAndroid Build Coastguard Worker for (int y = 0; y < dim.fHeight; ++y) {
45*c8dee2aaSAndroid Build Coastguard Worker const uint8_t* row1 = reinterpret_cast<const uint8_t*>(bm[0].pixmap().addr32(0, y));
46*c8dee2aaSAndroid Build Coastguard Worker const uint8_t* row2 = reinterpret_cast<const uint8_t*>(bm[1].pixmap().addr32(0, y));
47*c8dee2aaSAndroid Build Coastguard Worker for (size_t i = 0; i < (size_t)dim.fWidth * (size_t)4; ++i) {
48*c8dee2aaSAndroid Build Coastguard Worker totalDiffs += std::abs((int)row1[i] - (int)row2[i]);
49*c8dee2aaSAndroid Build Coastguard Worker }
50*c8dee2aaSAndroid Build Coastguard Worker }
51*c8dee2aaSAndroid Build Coastguard Worker printf("%g\n", (double)totalDiffs /
52*c8dee2aaSAndroid Build Coastguard Worker ((uint64_t)255 * 4 * (uint64_t)dim.fWidth * (uint64_t)dim.fHeight));
53*c8dee2aaSAndroid Build Coastguard Worker return 0;
54*c8dee2aaSAndroid Build Coastguard Worker }
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