printing/image.cc

   1 // Copyright (c) 2011 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 "printing/image.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/file_util.h"
  10 #include "base/md5.h"
  11 #include "base/safe_numerics.h"
  12 #include "base/string_number_conversions.h"
  13 #include "printing/metafile.h"
  14 #include "printing/metafile_impl.h"
  15 #include "third_party/skia/include/core/SkColor.h"
  16 #include "ui/gfx/codec/png_codec.h"
  17
  18 namespace printing {
  19
  20 Image::Image(const base::FilePath& path)
  21     : row_length_(0),
  22       ignore_alpha_(true) {
  23   std::string data;
  24   file_util::ReadFileToString(path, &data);
  25   bool success = false;
  26   if (path.MatchesExtension(FILE_PATH_LITERAL(".png"))) {
  27     success = LoadPng(data);
  28   } else if (path.MatchesExtension(FILE_PATH_LITERAL(".emf"))) {
  29     success = LoadMetafile(data);
  30   } else {
  31     DCHECK(false);
  32   }
  33   if (!success) {
  34     size_.SetSize(0, 0);
  35     row_length_ = 0;
  36     data_.clear();
  37   }
  38 }
  39
  40 Image::Image(const Metafile& metafile)
  41     : row_length_(0),
  42       ignore_alpha_(true) {
  43   LoadMetafile(metafile);
  44 }
  45
  46 Image::Image(const Image& image)
  47     : size_(image.size_),
  48       row_length_(image.row_length_),
  49       data_(image.data_),
  50       ignore_alpha_(image.ignore_alpha_) {
  51 }
  52
  53 Image::~Image() {}
  54
  55 std::string Image::checksum() const {
  56   base::MD5Digest digest;
  57   base::MD5Sum(&data_[0], data_.size(), &digest);
  58   return base::HexEncode(&digest, sizeof(digest));
  59 }
  60
  61 bool Image::SaveToPng(const base::FilePath& filepath) const {
  62   DCHECK(!data_.empty());
  63   std::vector<unsigned char> compressed;
  64   bool success = gfx::PNGCodec::Encode(&*data_.begin(),
  65                                        gfx::PNGCodec::FORMAT_BGRA,
  66                                        size_,
  67                                        row_length_,
  68                                        true,
  69                                        std::vector<gfx::PNGCodec::Comment>(),
  70                                        &compressed);
  71   DCHECK(success && compressed.size());
  72   if (success) {
  73     int write_bytes = file_util::WriteFile(
  74         filepath,
  75         reinterpret_cast<char*>(&*compressed.begin()),
  76         base::checked_numeric_cast<int>(compressed.size()));
  77     success = (write_bytes == static_cast<int>(compressed.size()));
  78     DCHECK(success);
  79   }
  80   return success;
  81 }
  82
  83 double Image::PercentageDifferent(const Image& rhs) const {
  84   if (size_.width() == 0 || size_.height() == 0 ||
  85     rhs.size_.width() == 0 || rhs.size_.height() == 0)
  86     return 100.;
  87
  88   int width = std::min(size_.width(), rhs.size_.width());
  89   int height = std::min(size_.height(), rhs.size_.height());
  90   // Compute pixels different in the overlap
  91   int pixels_different = 0;
  92   for (int y = 0; y < height; ++y) {
  93     for (int x = 0; x < width; ++x) {
  94       uint32 lhs_pixel = pixel_at(x, y);
  95       uint32 rhs_pixel = rhs.pixel_at(x, y);
  96       if (lhs_pixel != rhs_pixel)
  97         ++pixels_different;
  98     }
  99
 100     // Look for extra right lhs pixels. They should be white.
 101     for (int x = width; x < size_.width(); ++x) {
 102       uint32 lhs_pixel = pixel_at(x, y);
 103       if (lhs_pixel != Color(SK_ColorWHITE))
 104         ++pixels_different;
 105     }
 106
 107     // Look for extra right rhs pixels. They should be white.
 108     for (int x = width; x < rhs.size_.width(); ++x) {
 109       uint32 rhs_pixel = rhs.pixel_at(x, y);
 110       if (rhs_pixel != Color(SK_ColorWHITE))
 111         ++pixels_different;
 112     }
 113   }
 114
 115   // Look for extra bottom lhs pixels. They should be white.
 116   for (int y = height; y < size_.height(); ++y) {
 117     for (int x = 0; x < size_.width(); ++x) {
 118       uint32 lhs_pixel = pixel_at(x, y);
 119       if (lhs_pixel != Color(SK_ColorWHITE))
 120         ++pixels_different;
 121     }
 122   }
 123
 124   // Look for extra bottom rhs pixels. They should be white.
 125   for (int y = height; y < rhs.size_.height(); ++y) {
 126     for (int x = 0; x < rhs.size_.width(); ++x) {
 127       uint32 rhs_pixel = rhs.pixel_at(x, y);
 128       if (rhs_pixel != Color(SK_ColorWHITE))
 129         ++pixels_different;
 130     }
 131   }
 132
 133   // Like the WebKit ImageDiff tool, we define percentage different in terms
 134   // of the size of the 'actual' bitmap.
 135   double total_pixels = static_cast<double>(size_.width()) *
 136       static_cast<double>(height);
 137   return static_cast<double>(pixels_different) / total_pixels * 100.;
 138 }
 139
 140 bool Image::LoadPng(const std::string& compressed) {
 141   int w;
 142   int h;
 143   bool success = gfx::PNGCodec::Decode(
 144       reinterpret_cast<const unsigned char*>(compressed.c_str()),
 145       compressed.size(), gfx::PNGCodec::FORMAT_BGRA, &data_, &w, &h);
 146   size_.SetSize(w, h);
 147   row_length_ = size_.width() * sizeof(uint32);
 148   return success;
 149 }
 150
 151 bool Image::LoadMetafile(const std::string& data) {
 152   DCHECK(!data.empty());
 153   NativeMetafile metafile;
 154   if (!metafile.InitFromData(data.data(),
 155                              base::checked_numeric_cast<uint32>(data.size())))
 156     return false;
 157   return LoadMetafile(metafile);
 158 }
 159
 160 }  // namespace printing