printing/metafile.h

   1 // Copyright (c) 2011 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_METAFILE_H_
   6 #define PRINTING_METAFILE_H_
   7
   8 #include "base/basictypes.h"
   9 #include "build/build_config.h"
  10 #include "printing/printing_export.h"
  11 #include "ui/gfx/native_widget_types.h"
  12
  13 #if defined(OS_WIN)
  14 #include <windows.h>
  15 #elif defined(OS_MACOSX)
  16 #include <ApplicationServices/ApplicationServices.h>
  17 #include <CoreFoundation/CoreFoundation.h>
  18 #include "base/mac/scoped_cftyperef.h"
  19 #endif
  20
  21 class FilePath;
  22
  23 namespace gfx {
  24 class Rect;
  25 class Size;
  26 }
  27
  28 class SkDevice;
  29
  30 #if defined(OS_CHROMEOS)
  31 namespace base {
  32 struct FileDescriptor;
  33 }
  34 #endif
  35
  36 namespace printing {
  37
  38 // This class creates a graphics context that renders into a data stream
  39 // (usually PDF or EMF).
  40 class PRINTING_EXPORT Metafile {
  41  public:
  42   virtual ~Metafile() {}
  43
  44   // Initializes a fresh new metafile for rendering. Returns false on failure.
  45   // Note: It should only be called from within the renderer process to allocate
  46   // rendering resources.
  47   virtual bool Init() = 0;
  48
  49   // Initializes the metafile with the data in |src_buffer|. Returns true
  50   // on success.
  51   // Note: It should only be called from within the browser process.
  52   virtual bool InitFromData(const void* src_buffer, uint32 src_buffer_size) = 0;
  53
  54   // This method calls StartPage and then returns an appropriate
  55   // VectorPlatformDevice implementation bound to the context created by
  56   // StartPage or NULL on error.
  57   virtual SkDevice* StartPageForVectorCanvas(
  58       const gfx::Size& page_size,
  59       const gfx::Rect& content_area,
  60       const float& scale_factor) = 0;
  61
  62   // Prepares a context for rendering a new page with the given |page_size|,
  63   // |content_area| and  a |scale_factor| to use for the drawing. The units are
  64   // in points (=1/72 in). Returns true on success.
  65   virtual bool StartPage(const gfx::Size& page_size,
  66                          const gfx::Rect& content_area,
  67                          const float& scale_factor) = 0;
  68
  69   // Closes the current page and destroys the context used in rendering that
  70   // page. The results of current page will be appended into the underlying
  71   // data stream. Returns true on success.
  72   virtual bool FinishPage() = 0;
  73
  74   // Closes the metafile. No further rendering is allowed (the current page
  75   // is implicitly closed).
  76   virtual bool FinishDocument() = 0;
  77
  78   // Returns the size of the underlying data stream. Only valid after Close()
  79   // has been called.
  80   virtual uint32 GetDataSize() const = 0;
  81
  82   // Copies the first |dst_buffer_size| bytes of the underlying data stream into
  83   // |dst_buffer|. This function should ONLY be called after Close() is invoked.
  84   // Returns true if the copy succeeds.
  85   virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const = 0;
  86
  87   // Saves the underlying data to the given file. This function should ONLY be
  88   // called after the metafile is closed. Returns true if writing succeeded.
  89   virtual bool SaveTo(const FilePath& file_path) const = 0;
  90
  91   // Returns the bounds of the given page. Pages use a 1-based index.
  92   virtual gfx::Rect GetPageBounds(unsigned int page_number) const = 0;
  93   virtual unsigned int GetPageCount() const = 0;
  94
  95   // Get the context for rendering to the PDF.
  96   virtual gfx::NativeDrawingContext context() const = 0;
  97
  98 #if defined(OS_WIN)
  99   // "Plays" the EMF buffer in a HDC. It is the same effect as calling the
 100   // original GDI function that were called when recording the EMF. |rect| is in
 101   // "logical units" and is optional. If |rect| is NULL, the natural EMF bounds
 102   // are used.
 103   // Note: Windows has been known to have stack buffer overflow in its GDI
 104   // functions, whether used directly or indirectly through precompiled EMF
 105   // data. We have to accept the risk here. Since it is used only for printing,
 106   // it requires user intervention.
 107   virtual bool Playback(gfx::NativeDrawingContext hdc,
 108                         const RECT* rect) const = 0;
 109
 110   // The slow version of Playback(). It enumerates all the records and play them
 111   // back in the HDC. The trick is that it skip over the records known to have
 112   // issue with some printers. See Emf::Record::SafePlayback implementation for
 113   // details.
 114   virtual bool SafePlayback(gfx::NativeDrawingContext hdc) const = 0;
 115
 116   virtual HENHMETAFILE emf() const = 0;
 117 #elif defined(OS_MACOSX)
 118   // Renders the given page into |rect| in the given context.
 119   // Pages use a 1-based index. The rendering uses the following arguments
 120   // to determine scaling and translation factors.
 121   // |shrink_to_fit| specifies whether the output should be shrunk to fit the
 122   // supplied |rect| if the page size is larger than |rect| in any dimension.
 123   // If this is false, parts of the PDF page that lie outside the bounds will be
 124   // clipped.
 125   // |stretch_to_fit| specifies whether the output should be stretched to fit
 126   // the supplied bounds if the page size is smaller than |rect| in all
 127   // dimensions.
 128   // |center_horizontally| specifies whether the final image (after any scaling
 129   // is done) should be centered horizontally within the given |rect|.
 130   // |center_vertically| specifies whether the final image (after any scaling
 131   // is done) should be centered vertically within the given |rect|.
 132   // Note that all scaling preserves the original aspect ratio of the page.
 133   virtual bool RenderPage(unsigned int page_number,
 134                           gfx::NativeDrawingContext context,
 135                           const CGRect rect,
 136                           bool shrink_to_fit,
 137                           bool stretch_to_fit,
 138                           bool center_horizontally,
 139                           bool center_vertically) const = 0;
 140 #elif defined(OS_CHROMEOS)
 141   // Saves the underlying data to the file associated with fd. This function
 142   // should ONLY be called after the metafile is closed.
 143   // Returns true if writing succeeded.
 144   virtual bool SaveToFD(const base::FileDescriptor& fd) const = 0;
 145 #endif  // if defined(OS_CHROMEOS)
 146 };
 147
 148 }  // namespace printing
 149
 150 #endif  // PRINTING_METAFILE_H_