1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7#include "skdiff.h"
8#include "skdiff_utils.h"
9#include "SkBitmap.h"
10#include "SkData.h"
11#include "SkImageDecoder.h"
12#include "SkImageEncoder.h"
13#include "SkStream.h"
14#include "SkTemplates.h"
15#include "SkTypes.h"
16
17bool are_buffers_equal(SkData* skdata1, SkData* skdata2) {
18    if ((NULL == skdata1) || (NULL == skdata2)) {
19        return false;
20    }
21    if (skdata1->size() != skdata2->size()) {
22        return false;
23    }
24    return (0 == memcmp(skdata1->data(), skdata2->data(), skdata1->size()));
25}
26
27SkData* read_file(const char* file_path) {
28    SkData* data = SkData::NewFromFileName(file_path);
29    if (!data) {
30        SkDebugf("WARNING: could not open file <%s> for reading\n", file_path);
31    }
32    return data;
33}
34
35bool get_bitmap(SkData* fileBits, DiffResource& resource, SkImageDecoder::Mode mode) {
36    SkMemoryStream stream(fileBits->data(), fileBits->size());
37
38    SkImageDecoder* codec = SkImageDecoder::Factory(&stream);
39    if (NULL == codec) {
40        SkDebugf("ERROR: no codec found for <%s>\n", resource.fFullPath.c_str());
41        resource.fStatus = DiffResource::kCouldNotDecode_Status;
42        return false;
43    }
44
45    // In debug, the DLL will automatically be unloaded when this is deleted,
46    // but that shouldn't be a problem in release mode.
47    SkAutoTDelete<SkImageDecoder> ad(codec);
48
49    stream.rewind();
50    if (!codec->decode(&stream, &resource.fBitmap, kN32_SkColorType, mode)) {
51        SkDebugf("ERROR: codec failed for basePath <%s>\n", resource.fFullPath.c_str());
52        resource.fStatus = DiffResource::kCouldNotDecode_Status;
53        return false;
54    }
55
56    resource.fStatus = DiffResource::kDecoded_Status;
57    return true;
58}
59
60/** Thanks to PNG, we need to force all pixels 100% opaque. */
61static void force_all_opaque(const SkBitmap& bitmap) {
62   SkAutoLockPixels lock(bitmap);
63   for (int y = 0; y < bitmap.height(); y++) {
64       for (int x = 0; x < bitmap.width(); x++) {
65           *bitmap.getAddr32(x, y) |= (SK_A32_MASK << SK_A32_SHIFT);
66       }
67   }
68}
69
70bool write_bitmap(const SkString& path, const SkBitmap& bitmap) {
71    SkBitmap copy;
72    bitmap.copyTo(&copy, kN32_SkColorType);
73    force_all_opaque(copy);
74    return SkImageEncoder::EncodeFile(path.c_str(), copy,
75                                      SkImageEncoder::kPNG_Type, 100);
76}
77
78/// Return a copy of the "input" string, within which we have replaced all instances
79/// of oldSubstring with newSubstring.
80///
81/// TODO: If we like this, we should move it into the core SkString implementation,
82/// adding more checks and ample test cases, and paying more attention to efficiency.
83static SkString replace_all(const SkString &input,
84                            const char oldSubstring[], const char newSubstring[]) {
85    SkString output;
86    const char *input_cstr = input.c_str();
87    const char *first_char = input_cstr;
88    const char *match_char;
89    size_t oldSubstringLen = strlen(oldSubstring);
90    while ((match_char = strstr(first_char, oldSubstring))) {
91        output.append(first_char, (match_char - first_char));
92        output.append(newSubstring);
93        first_char = match_char + oldSubstringLen;
94    }
95    output.append(first_char);
96    return output;
97}
98
99static SkString filename_to_derived_filename(const SkString& filename, const char *suffix) {
100    SkString diffName (filename);
101    const char* cstring = diffName.c_str();
102    size_t dotOffset = strrchr(cstring, '.') - cstring;
103    diffName.remove(dotOffset, diffName.size() - dotOffset);
104    diffName.append(suffix);
105
106    // In case we recursed into subdirectories, replace slashes with something else
107    // so the diffs will all be written into a single flat directory.
108    diffName = replace_all(diffName, PATH_DIV_STR, "_");
109    return diffName;
110}
111
112SkString filename_to_diff_filename(const SkString& filename) {
113    return filename_to_derived_filename(filename, "-diff.png");
114}
115
116SkString filename_to_white_filename(const SkString& filename) {
117    return filename_to_derived_filename(filename, "-white.png");
118}
119
120void create_and_write_diff_image(DiffRecord* drp,
121                                 DiffMetricProc dmp,
122                                 const int colorThreshold,
123                                 const SkString& outputDir,
124                                 const SkString& filename) {
125    const int w = drp->fBase.fBitmap.width();
126    const int h = drp->fBase.fBitmap.height();
127
128    if (w != drp->fComparison.fBitmap.width() || h != drp->fComparison.fBitmap.height()) {
129        drp->fResult = DiffRecord::kDifferentSizes_Result;
130    } else {
131        drp->fDifference.fBitmap.allocN32Pixels(w, h);
132
133        drp->fWhite.fBitmap.allocN32Pixels(w, h);
134
135        SkASSERT(DiffRecord::kUnknown_Result == drp->fResult);
136        compute_diff(drp, dmp, colorThreshold);
137        SkASSERT(DiffRecord::kUnknown_Result != drp->fResult);
138    }
139
140    if (outputDir.isEmpty()) {
141        drp->fDifference.fStatus = DiffResource::kUnspecified_Status;
142        drp->fWhite.fStatus = DiffResource::kUnspecified_Status;
143
144    } else {
145        drp->fDifference.fFilename = filename_to_diff_filename(filename);
146        drp->fDifference.fFullPath = outputDir;
147        drp->fDifference.fFullPath.append(drp->fDifference.fFilename);
148        drp->fDifference.fStatus = DiffResource::kSpecified_Status;
149
150        drp->fWhite.fFilename = filename_to_white_filename(filename);
151        drp->fWhite.fFullPath = outputDir;
152        drp->fWhite.fFullPath.append(drp->fWhite.fFilename);
153        drp->fWhite.fStatus = DiffResource::kSpecified_Status;
154
155        if (DiffRecord::kDifferentPixels_Result == drp->fResult) {
156            if (write_bitmap(drp->fDifference.fFullPath, drp->fDifference.fBitmap)) {
157                drp->fDifference.fStatus = DiffResource::kExists_Status;
158            } else {
159                drp->fDifference.fStatus = DiffResource::kDoesNotExist_Status;
160            }
161            if (write_bitmap(drp->fWhite.fFullPath, drp->fWhite.fBitmap)) {
162                drp->fWhite.fStatus = DiffResource::kExists_Status;
163            } else {
164                drp->fWhite.fStatus = DiffResource::kDoesNotExist_Status;
165            }
166        }
167    }
168}
169