printing/emf_win.h

   1 // Copyright (c) 2012 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 #ifndef PRINTING_EMF_WIN_H_
   6 #define PRINTING_EMF_WIN_H_
   7
   8 #include <windows.h>
   9
  10 #include <vector>
  11
  12 #include "base/basictypes.h"
  13 #include "base/compiler_specific.h"
  14 #include "base/gtest_prod_util.h"
  15 #include "printing/metafile.h"
  16
  17 namespace base {
  18 class FilePath;
  19 }
  20
  21 namespace gfx {
  22 class Rect;
  23 class Size;
  24 }
  25
  26 namespace printing {
  27
  28 // http://msdn2.microsoft.com/en-us/library/ms535522.aspx
  29 // Windows 2000/XP: When a page in a spooled file exceeds approximately 350
  30 // MB, it can fail to print and not send an error message.
  31 const size_t kMetafileMaxSize = 350*1024*1024;
  32
  33 // Simple wrapper class that manage an EMF data stream and its virtual HDC.
  34 class PRINTING_EXPORT Emf : public Metafile {
  35  public:
  36   class Record;
  37   class Enumerator;
  38   struct EnumerationContext;
  39
  40   // Generates a virtual HDC that will record every GDI commands and compile
  41   // it in a EMF data stream.
  42   Emf();
  43   virtual ~Emf();
  44
  45   // Closes metafile.
  46   void Close();
  47
  48   // Generates a new metafile that will record every GDI command, and will
  49   // be saved to |metafile_path|.
  50   virtual bool InitToFile(const base::FilePath& metafile_path);
  51
  52   // Initializes the Emf with the data in |metafile_path|.
  53   virtual bool InitFromFile(const base::FilePath& metafile_path);
  54
  55   // Metafile methods.
  56   virtual bool Init() OVERRIDE;
  57   virtual bool InitFromData(const void* src_buffer,
  58                             uint32 src_buffer_size) OVERRIDE;
  59
  60   virtual SkBaseDevice* StartPageForVectorCanvas(
  61       const gfx::Size& page_size, const gfx::Rect& content_area,
  62       const float& scale_factor) OVERRIDE;
  63   // Inserts a custom GDICOMMENT records indicating StartPage/EndPage calls
  64   // (since StartPage and EndPage do not work in a metafile DC). Only valid
  65   // when hdc_ is non-NULL. |page_size|, |content_area|, and |scale_factor| are
  66   // ignored.
  67   virtual bool StartPage(const gfx::Size& page_size,
  68                          const gfx::Rect& content_area,
  69                          const float& scale_factor) OVERRIDE;
  70   virtual bool FinishPage() OVERRIDE;
  71   virtual bool FinishDocument() OVERRIDE;
  72
  73   virtual uint32 GetDataSize() const OVERRIDE;
  74   virtual bool GetData(void* buffer, uint32 size) const OVERRIDE;
  75
  76   // Saves the EMF data to a file as-is. It is recommended to use the .emf file
  77   // extension but it is not enforced. This function synchronously writes to the
  78   // file. For testing only.
  79   virtual bool SaveTo(const base::FilePath& file_path) const OVERRIDE;
  80
  81   // Should be passed to Playback to keep the exact same size.
  82   virtual gfx::Rect GetPageBounds(unsigned int page_number) const OVERRIDE;
  83
  84   virtual unsigned int GetPageCount() const OVERRIDE {
  85     return page_count_;
  86   }
  87
  88   virtual HDC context() const OVERRIDE {
  89     return hdc_;
  90   }
  91
  92   virtual bool Playback(HDC hdc, const RECT* rect) const OVERRIDE;
  93   virtual bool SafePlayback(HDC hdc) const OVERRIDE;
  94
  95   virtual HENHMETAFILE emf() const OVERRIDE {
  96     return emf_;
  97   }
  98
  99   // Returns true if metafile contains alpha blend.
 100   bool IsAlphaBlendUsed() const;
 101
 102   // Returns new metafile with only bitmap created by playback of the current
 103   // metafile. Returns NULL if fails.
 104   Emf* RasterizeMetafile(int raster_area_in_pixels) const;
 105
 106   // Returns new metafile where AlphaBlend replaced by bitmaps. Returns NULL
 107   // if fails.
 108   Emf* RasterizeAlphaBlend() const;
 109
 110  private:
 111   FRIEND_TEST_ALL_PREFIXES(EmfTest, DC);
 112   FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, PageBreak);
 113   FRIEND_TEST_ALL_PREFIXES(EmfTest, FileBackedEmf);
 114
 115   // Retrieves the underlying data stream. It is a helper function.
 116   bool GetDataAsVector(std::vector<uint8>* buffer) const;
 117
 118   // Playbacks safely one EMF record.
 119   static int CALLBACK SafePlaybackProc(HDC hdc,
 120                                        HANDLETABLE* handle_table,
 121                                        const ENHMETARECORD* record,
 122                                        int objects_count,
 123                                        LPARAM param);
 124
 125   // Compiled EMF data handle.
 126   HENHMETAFILE emf_;
 127
 128   // Valid when generating EMF data through a virtual HDC.
 129   HDC hdc_;
 130
 131   int page_count_;
 132
 133   DISALLOW_COPY_AND_ASSIGN(Emf);
 134 };
 135
 136 struct Emf::EnumerationContext {
 137   EnumerationContext();
 138
 139   HANDLETABLE* handle_table;
 140   int objects_count;
 141   HDC hdc;
 142   const XFORM* base_matrix;
 143   int dc_on_page_start;
 144 };
 145
 146 // One EMF record. It keeps pointers to the EMF buffer held by Emf::emf_.
 147 // The entries become invalid once Emf::CloseEmf() is called.
 148 class PRINTING_EXPORT Emf::Record {
 149  public:
 150   // Plays the record.
 151   bool Play(EnumerationContext* context) const;
 152
 153   // Plays the record working around quirks with SetLayout,
 154   // SetWorldTransform and ModifyWorldTransform. See implementation for details.
 155   bool SafePlayback(EnumerationContext* context) const;
 156
 157   // Access the underlying EMF record.
 158   const ENHMETARECORD* record() const { return record_; }
 159
 160  protected:
 161   explicit Record(const ENHMETARECORD* record);
 162
 163  private:
 164   friend class Emf;
 165   friend class Enumerator;
 166   const ENHMETARECORD* record_;
 167 };
 168
 169 // Retrieves individual records out of a Emf buffer. The main use is to skip
 170 // over records that are unsupported on a specific printer or to play back
 171 // only a part of an EMF buffer.
 172 class PRINTING_EXPORT Emf::Enumerator {
 173  public:
 174   // Iterator type used for iterating the records.
 175   typedef std::vector<Record>::const_iterator const_iterator;
 176
 177   // Enumerates the records at construction time. |hdc| and |rect| are
 178   // both optional at the same time or must both be valid.
 179   // Warning: |emf| must be kept valid for the time this object is alive.
 180   Enumerator(const Emf& emf, HDC hdc, const RECT* rect);
 181
 182   // Retrieves the first Record.
 183   const_iterator begin() const;
 184
 185   // Retrieves the end of the array.
 186   const_iterator end() const;
 187
 188  private:
 189   FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, Enumerate);
 190
 191   // Processes one EMF record and saves it in the items_ array.
 192   static int CALLBACK EnhMetaFileProc(HDC hdc,
 193                                       HANDLETABLE* handle_table,
 194                                       const ENHMETARECORD* record,
 195                                       int objects_count,
 196                                       LPARAM param);
 197
 198   // The collection of every EMF records in the currently loaded EMF buffer.
 199   // Initialized by Enumerate(). It keeps pointers to the EMF buffer held by
 200   // Emf::emf_. The entries become invalid once Emf::CloseEmf() is called.
 201   std::vector<Record> items_;
 202
 203   EnumerationContext context_;
 204
 205   DISALLOW_COPY_AND_ASSIGN(Enumerator);
 206 };
 207
 208 }  // namespace printing
 209
 210 #endif  // PRINTING_EMF_WIN_H_