printing/pdf_ps_metafile_cairo.h

   1 // Copyright (c) 2010 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_PDF_PS_METAFILE_CAIRO_H_
   6 #define PRINTING_PDF_PS_METAFILE_CAIRO_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11
  12 typedef struct _cairo_surface cairo_surface_t;
  13 typedef struct _cairo cairo_t;
  14
  15 namespace base {
  16 struct FileDescriptor;
  17 }
  18
  19 class FilePath;
  20
  21 namespace printing {
  22
  23 // This class uses Cairo graphics library to generate PostScript/PDF stream
  24 // and stores rendering results in a string buffer.
  25 class PdfPsMetafile {
  26  public:
  27   enum FileFormat {
  28     PDF,
  29     PS,
  30   };
  31
  32   PdfPsMetafile();
  33
  34   // In the renderer process, callers should also call Init(void) to see if the
  35   // metafile can obtain all necessary rendering resources.
  36   // In the browser process, callers should also call Init(const void*, uint32)
  37   // to initialize the buffer |data_| to use SaveTo().
  38   explicit PdfPsMetafile(const FileFormat& format);
  39
  40   ~PdfPsMetafile();
  41
  42   // Initializes to a fresh new metafile. Returns true on success.
  43   // Note: Only call in the renderer to allocate rendering resources.
  44   bool Init();
  45
  46   // Initializes a copy of metafile from PDF/PS stream data.
  47   // Returns true on success.
  48   // |src_buffer| should point to the shared memory which stores PDF/PS
  49   // contents generated in the renderer.
  50   // Note: Only call in the browser to initialize |data_|.
  51   bool Init(const void* src_buffer, uint32 src_buffer_size);
  52
  53   // Sets raw PS/PDF data for the document. This is used when a cairo drawing
  54   // surface has already been created. This method will cause all subsequent
  55   // drawing on the surface to be discarded (in Close()). If Init() has not yet
  56   // been called this method simply calls the second version of Init.
  57   bool SetRawData(const void* src_buffer, uint32 src_buffer_size);
  58
  59   FileFormat GetFileFormat() const { return format_; }
  60
  61   // Prepares a new cairo surface/context for rendering a new page.
  62   // The unit is in point (=1/72 in).
  63   // Returns NULL when failed.
  64   cairo_t* StartPage(double width_in_points,
  65                      double height_in_points,
  66                      double margin_top_in_points,
  67                      double margin_right_in_points,
  68                      double margin_bottom_in_points,
  69                      double margin_left_in_points);
  70
  71   // Destroys the surface and the context used in rendering current page.
  72   // The results of current page will be appended into buffer |data_|.
  73   // Returns true on success.
  74   bool FinishPage();
  75
  76   // Closes resulting PDF/PS file. No further rendering is allowed.
  77   void Close();
  78
  79   // Returns size of PDF/PS contents stored in buffer |data_|.
  80   // This function should ONLY be called after PDF/PS file is closed.
  81   uint32 GetDataSize() const;
  82
  83   // Copies PDF/PS contents stored in buffer |data_| into |dst_buffer|.
  84   // This function should ONLY be called after PDF/PS file is closed.
  85   // Returns true only when success.
  86   bool GetData(void* dst_buffer, uint32 dst_buffer_size) const;
  87
  88   // Saves PDF/PS contents stored in buffer |data_| into the file
  89   // associated with |fd|.
  90   // This function should ONLY be called after PDF/PS file is closed.
  91   bool SaveTo(const base::FileDescriptor& fd) const;
  92
  93   // The hardcoded margins, in points. These values are based on 72 dpi,
  94   // with 0.25 margins on top, left, and right, and 0.56 on bottom.
  95   static const double kTopMarginInInch;
  96   static const double kRightMarginInInch;
  97   static const double kBottomMarginInInch;
  98   static const double kLeftMarginInInch;
  99
 100   // Returns the PdfPsMetafile object that owns the given context. Returns NULL
 101   // if the context was not created by a PdfPdMetafile object.
 102   static PdfPsMetafile* FromCairoContext(cairo_t* context);
 103
 104  private:
 105   // Cleans up all resources.
 106   void CleanUpAll();
 107
 108   FileFormat format_;
 109
 110   // Cairo surface and context for entire PDF/PS file.
 111   cairo_surface_t* surface_;
 112   cairo_t* context_;
 113
 114   // Buffer stores PDF/PS contents for entire PDF/PS file.
 115   std::string data_;
 116   // Buffer stores raw PDF/PS contents set by SetRawPageData.
 117   std::string raw_override_data_;
 118
 119   DISALLOW_COPY_AND_ASSIGN(PdfPsMetafile);
 120 };
 121
 122 }  // namespace printing
 123
 124 #endif  // PRINTING_PDF_PS_METAFILE_CAIRO_H_