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