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   ~Emf() override;
  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   bool Init() override;
  58   bool InitFromData(const void* src_buffer,
  59                     uint32 src_buffer_size) override;
  60
  61   // Inserts a custom GDICOMMENT records indicating StartPage/EndPage calls
  62   // (since StartPage and EndPage do not work in a metafile DC). Only valid
  63   // when hdc_ is non-NULL. |page_size|, |content_area|, and |scale_factor| are
  64   // ignored.
  65   bool StartPage(const gfx::Size& page_size,
  66                  const gfx::Rect& content_area,
  67                  const float& scale_factor) override;
  68   bool FinishPage() override;
  69   bool FinishDocument() override;
  70
  71   uint32 GetDataSize() const override;
  72   bool GetData(void* buffer, uint32 size) const override;
  73
  74   // Should be passed to Playback to keep the exact same size.
  75   gfx::Rect GetPageBounds(unsigned int page_number) const override;
  76
  77   unsigned int GetPageCount() const override;
  78   HDC context() const override;
  79   bool Playback(HDC hdc, const RECT* rect) const override;
  80   bool SafePlayback(HDC hdc) const override;
  81
  82   HENHMETAFILE emf() const { return emf_; }
  83
  84   // Returns true if metafile contains alpha blend.
  85   bool IsAlphaBlendUsed() const;
  86
  87   // Returns new metafile with only bitmap created by playback of the current
  88   // metafile. Returns NULL if fails.
  89   scoped_ptr<Emf> RasterizeMetafile(int raster_area_in_pixels) const;
  90
  91   // Returns new metafile where AlphaBlend replaced by bitmaps. Returns NULL
  92   // if fails.
  93   scoped_ptr<Emf> RasterizeAlphaBlend() const;
  94
  95  private:
  96   FRIEND_TEST_ALL_PREFIXES(EmfTest, DC);
  97   FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, PageBreak);
  98   FRIEND_TEST_ALL_PREFIXES(EmfTest, FileBackedEmf);
  99
 100   // Playbacks safely one EMF record.
 101   static int CALLBACK SafePlaybackProc(HDC hdc,
 102                                        HANDLETABLE* handle_table,
 103                                        const ENHMETARECORD* record,
 104                                        int objects_count,
 105                                        LPARAM param);
 106
 107   // Compiled EMF data handle.
 108   HENHMETAFILE emf_;
 109
 110   // Valid when generating EMF data through a virtual HDC.
 111   HDC hdc_;
 112
 113   DISALLOW_COPY_AND_ASSIGN(Emf);
 114 };
 115
 116 struct Emf::EnumerationContext {
 117   EnumerationContext();
 118
 119   HANDLETABLE* handle_table;
 120   int objects_count;
 121   HDC hdc;
 122   const XFORM* base_matrix;
 123   int dc_on_page_start;
 124 };
 125
 126 // One EMF record. It keeps pointers to the EMF buffer held by Emf::emf_.
 127 // The entries become invalid once Emf::CloseEmf() is called.
 128 class PRINTING_EXPORT Emf::Record {
 129  public:
 130   // Plays the record.
 131   bool Play(EnumerationContext* context) const;
 132
 133   // Plays the record working around quirks with SetLayout,
 134   // SetWorldTransform and ModifyWorldTransform. See implementation for details.
 135   bool SafePlayback(EnumerationContext* context) const;
 136
 137   // Access the underlying EMF record.
 138   const ENHMETARECORD* record() const { return record_; }
 139
 140  protected:
 141   explicit Record(const ENHMETARECORD* record);
 142
 143  private:
 144   friend class Emf;
 145   friend class Enumerator;
 146   const ENHMETARECORD* record_;
 147 };
 148
 149 // Retrieves individual records out of a Emf buffer. The main use is to skip
 150 // over records that are unsupported on a specific printer or to play back
 151 // only a part of an EMF buffer.
 152 class PRINTING_EXPORT Emf::Enumerator {
 153  public:
 154   // Iterator type used for iterating the records.
 155   typedef std::vector<Record>::const_iterator const_iterator;
 156
 157   // Enumerates the records at construction time. |hdc| and |rect| are
 158   // both optional at the same time or must both be valid.
 159   // Warning: |emf| must be kept valid for the time this object is alive.
 160   Enumerator(const Emf& emf, HDC hdc, const RECT* rect);
 161
 162   ~Enumerator();
 163
 164   // Retrieves the first Record.
 165   const_iterator begin() const;
 166
 167   // Retrieves the end of the array.
 168   const_iterator end() const;
 169
 170  private:
 171   FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, Enumerate);
 172
 173   // Processes one EMF record and saves it in the items_ array.
 174   static int CALLBACK EnhMetaFileProc(HDC hdc,
 175                                       HANDLETABLE* handle_table,
 176                                       const ENHMETARECORD* record,
 177                                       int objects_count,
 178                                       LPARAM param);
 179
 180   // The collection of every EMF records in the currently loaded EMF buffer.
 181   // Initialized by Enumerate(). It keeps pointers to the EMF buffer held by
 182   // Emf::emf_. The entries become invalid once Emf::CloseEmf() is called.
 183   std::vector<Record> items_;
 184
 185   EnumerationContext context_;
 186
 187   DISALLOW_COPY_AND_ASSIGN(Enumerator);
 188 };
 189
 190 }  // namespace printing
 191
 192 #endif  // PRINTING_EMF_WIN_H_