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