text: // Copyright (c) 2012 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_EMF_WIN_H_
  #define PRINTING_EMF_WIN_H_
  
  #include <windows.h>
  
  #include <vector>
  
  #include "base/basictypes.h"
  #include "base/compiler_specific.h"
  #include "base/gtest_prod_util.h"
  #include "base/memory/scoped_ptr.h"
  #include "printing/metafile.h"
  
  namespace base {
  class FilePath;
  }
  
  namespace gfx {
  class Rect;
  class Size;
  }
  
  namespace printing {
  
  // http://msdn2.microsoft.com/en-us/library/ms535522.aspx
  // Windows 2000/XP: When a page in a spooled file exceeds approximately 350
  // MB, it can fail to print and not send an error message.
  const size_t kMetafileMaxSize = 350*1024*1024;
  
  // Simple wrapper class that manage an EMF data stream and its virtual HDC.
  class PRINTING_EXPORT Emf : public Metafile {
   public:
    class Record;
    class Enumerator;
    struct EnumerationContext;
  
    // Generates a virtual HDC that will record every GDI commands and compile
    // it in a EMF data stream.
    Emf();
    ~Emf() override;
  
    // Closes metafile.
    void Close();
  
    // Generates a new metafile that will record every GDI command, and will
    // be saved to |metafile_path|.
    bool InitToFile(const base::FilePath& metafile_path);
  
    // Initializes the Emf with the data in |metafile_path|.
    bool InitFromFile(const base::FilePath& metafile_path);
  
    // Metafile methods.
    bool Init() override;
    bool InitFromData(const void* src_buffer,
                      uint32_t src_buffer_size) override;
  
    // Inserts a custom GDICOMMENT records indicating StartPage/EndPage calls
    // (since StartPage and EndPage do not work in a metafile DC). Only valid
    // when hdc_ is non-NULL. |page_size|, |content_area|, and |scale_factor| are
    // ignored.
    bool StartPage(const gfx::Size& page_size,
                   const gfx::Rect& content_area,
                   const float& scale_factor) override;
    bool FinishPage() override;
    bool FinishDocument() override;
  
    uint32_t GetDataSize() const override;
    bool GetData(void* buffer, uint32_t size) const override;
  
    // Should be passed to Playback to keep the exact same size.
    gfx::Rect GetPageBounds(unsigned int page_number) const override;
  
    unsigned int GetPageCount() const override;
    HDC context() const override;
    bool Playback(HDC hdc, const RECT* rect) const override;
    bool SafePlayback(HDC hdc) const override;
  
    HENHMETAFILE emf() const { return emf_; }
  
    // Returns true if metafile contains alpha blend.
    bool IsAlphaBlendUsed() const;
  
    // Returns new metafile with only bitmap created by playback of the current
    // metafile. Returns NULL if fails.
    scoped_ptr<Emf> RasterizeMetafile(int raster_area_in_pixels) const;
  
    // Returns new metafile where AlphaBlend replaced by bitmaps. Returns NULL
    // if fails.
    scoped_ptr<Emf> RasterizeAlphaBlend() const;
  
   private:
    FRIEND_TEST_ALL_PREFIXES(EmfTest, DC);
    FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, PageBreak);
    FRIEND_TEST_ALL_PREFIXES(EmfTest, FileBackedEmf);
  
    // Playbacks safely one EMF record.
    static int CALLBACK SafePlaybackProc(HDC hdc,
                                         HANDLETABLE* handle_table,
                                         const ENHMETARECORD* record,
                                         int objects_count,
                                         LPARAM param);
  
    // Compiled EMF data handle.
    HENHMETAFILE emf_;
  
    // Valid when generating EMF data through a virtual HDC.
    HDC hdc_;
  
    DISALLOW_COPY_AND_ASSIGN(Emf);
  };
  
  struct Emf::EnumerationContext {
    EnumerationContext();
  
    HANDLETABLE* handle_table;
    int objects_count;
    HDC hdc;
    const XFORM* base_matrix;
    int dc_on_page_start;
  };
  
  // One EMF record. It keeps pointers to the EMF buffer held by Emf::emf_.
  // The entries become invalid once Emf::CloseEmf() is called.
  class PRINTING_EXPORT Emf::Record {
   public:
    // Plays the record.
    bool Play(EnumerationContext* context) const;
  
    // Plays the record working around quirks with SetLayout,
    // SetWorldTransform and ModifyWorldTransform. See implementation for details.
    bool SafePlayback(EnumerationContext* context) const;
  
    // Access the underlying EMF record.
    const ENHMETARECORD* record() const { return record_; }
  
   protected:
    explicit Record(const ENHMETARECORD* record);
  
   private:
    friend class Emf;
    friend class Enumerator;
    const ENHMETARECORD* record_;
  };
  
  // Retrieves individual records out of a Emf buffer. The main use is to skip
  // over records that are unsupported on a specific printer or to play back
  // only a part of an EMF buffer.
  class PRINTING_EXPORT Emf::Enumerator {
   public:
    // Iterator type used for iterating the records.
    typedef std::vector<Record>::const_iterator const_iterator;
  
    // Enumerates the records at construction time. |hdc| and |rect| are
    // both optional at the same time or must both be valid.
    // Warning: |emf| must be kept valid for the time this object is alive.
    Enumerator(const Emf& emf, HDC hdc, const RECT* rect);
  
    ~Enumerator();
  
    // Retrieves the first Record.
    const_iterator begin() const;
  
    // Retrieves the end of the array.
    const_iterator end() const;
  
   private:
    FRIEND_TEST_ALL_PREFIXES(EmfPrintingTest, Enumerate);
  
    // Processes one EMF record and saves it in the items_ array.
    static int CALLBACK EnhMetaFileProc(HDC hdc,
                                        HANDLETABLE* handle_table,
                                        const ENHMETARECORD* record,
                                        int objects_count,
                                        LPARAM param);
  
    // The collection of every EMF records in the currently loaded EMF buffer.
    // Initialized by Enumerate(). It keeps pointers to the EMF buffer held by
    // Emf::emf_. The entries become invalid once Emf::CloseEmf() is called.
    std::vector<Record> items_;
  
    EnumerationContext context_;
  
    DISALLOW_COPY_AND_ASSIGN(Enumerator);
  };
  
  }  // namespace printing
  
  #endif  // PRINTING_EMF_WIN_H_
  