Print only the focused frame. This makes more sense than trying to print all...

printing/image.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PRINTING_IMAGE_H_
 #define PRINTING_IMAGE_H_
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/gfx/size.h"
 #include "base/logging.h"
+#include "printing/native_metafile.h"
 
 namespace printing {
 
-// Lightweight raw-bitmap management. The image, once initialized, is immuable.
+// Lightweight raw-bitmap management. The image, once initialized, is immutable.
 // The main purpose is testing image contents.
 class Image {
  public:
   // Creates the image from the given filename on disk.  Uses extension to
   // defer file type. PNG and EMF (on Windows) currently supported.
   // If image loading fails size().IsEmpty() will be true.
   explicit Image(const std::wstring& filename);
 
+  // Creates the image from the metafile.  Deduces bounds based on bounds in
+  // metafile.  If loading fails size().IsEmpty() will be true.
+  explicit Image(const NativeMetafile& metafile);
+
+  // Copy constructor.
+  explicit Image(const Image& image);
+
   const gfx::Size& size() const {
     return size_;
   }
 
+  // Return a checksum of the image (MD5 over the internal data structure).
+  std::string checksum() const;
+
   // Save image as PNG.
-  bool SaveToPng(const std::wstring& filename);
+  bool SaveToPng(const std::wstring& filename) const;
 
   // Returns % of pixels different
   double PercentageDifferent(const Image& rhs) const;
 
   // Returns the 0x0RGB or 0xARGB value of the pixel at the given location.
   uint32 Color(uint32 color) const {
     if (ignore_alpha_)
       return color & 0xFFFFFF;  // Strip out A.
     else
       return color;
   }
 
   uint32 pixel_at(int x, int y) const {
     DCHECK(x >= 0 && x < size_.width());
     DCHECK(y >= 0 && y < size_.height());
     const uint32* data = reinterpret_cast<const uint32*>(&*data_.begin());
     const uint32* data_row = data + y * row_length_ / sizeof(uint32);
     return Color(data_row[x]);
   }
 
  private:
+  // Construct from metafile.  This is kept internal since it's ambiguous what
+  // kind of data is used (png, bmp, metafile etc).
+  Image(const void* data, size_t size);
+
   bool LoadPng(const std::string& compressed);
 
   bool LoadMetafile(const std::string& data);
 
+  bool LoadMetafile(const NativeMetafile& metafile);
+
   // Pixel dimensions of the image.
   gfx::Size size_;
 
   // Length of a line in bytes.
   int row_length_;
 
   // Actual bitmap data in arrays of RGBAs (so when loaded as uint32, it's
   // 0xABGR).
   std::vector<unsigned char> data_;
 
   // Flag to signal if the comparison functions should ignore the alpha channel.
   const bool ignore_alpha_;  // Currently always true.
 
-  DISALLOW_EVIL_CONSTRUCTORS(Image);
+  // Prevent operator= (this function has no implementation)
+  Image& operator=(const Image& image);
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_IMAGE_H_