metafile.h revision 424c4d7b64af9d0d8fd9624f381f469654d5e3d2 
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_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
21namespace base {
22class FilePath;
23}
24
25namespace gfx {
26class Rect;
27class Size;
28}
29
30class SkBaseDevice;
31
32#if defined(OS_CHROMEOS) || defined(OS_ANDROID)
33namespace base {
34struct FileDescriptor;
35}
36#endif
37
38namespace printing {
39
40// This class creates a graphics context that renders into a data stream
41// (usually PDF or EMF).
42class PRINTING_EXPORT Metafile {
43 public:
44#if defined(OS_MACOSX)
45  // |shrink_to_fit| specifies whether the output should be shrunk to fit a
46  // destination page if the source PDF is bigger than the destination page in
47  // any dimension. If this is false, parts of the source PDF page that lie
48  // outside the bounds will be clipped.
49  // |stretch_to_fit| specifies whether the output should be stretched to fit
50  // the destination page if the source page size is smaller in all dimensions.
51  // |center_horizontally| specifies whether the output (after any scaling is
52  // done) should be centered horizontally within the destination page.
53  // |center_vertically| specifies whether the output (after any scaling is
54  // done) should be centered vertically within the destination page.
55  // Note that all scaling preserves the original aspect ratio of the page.
56  // |autorotate| specifies whether the source PDF should be autorotated to fit
57  // on the destination page.
58  struct MacRenderPageParams {
59    MacRenderPageParams()
60        : shrink_to_fit(false),
61          stretch_to_fit(false),
62          center_horizontally(false),
63          center_vertically(false),
64          autorotate(false) {
65    }
66
67    bool shrink_to_fit;
68    bool stretch_to_fit;
69    bool center_horizontally;
70    bool center_vertically;
71    bool autorotate;
72  };
73#endif  // defined(OS_MACOSX)
74
75  virtual ~Metafile() {}
76
77  // Initializes a fresh new metafile for rendering. Returns false on failure.
78  // Note: It should only be called from within the renderer process to allocate
79  // rendering resources.
80  virtual bool Init() = 0;
81
82  // Initializes the metafile with the data in |src_buffer|. Returns true
83  // on success.
84  // Note: It should only be called from within the browser process.
85  virtual bool InitFromData(const void* src_buffer, uint32 src_buffer_size) = 0;
86
87  // This method calls StartPage and then returns an appropriate
88  // VectorPlatformDevice implementation bound to the context created by
89  // StartPage or NULL on error.
90  virtual SkBaseDevice* StartPageForVectorCanvas(
91      const gfx::Size& page_size,
92      const gfx::Rect& content_area,
93      const float& scale_factor) = 0;
94
95  // Prepares a context for rendering a new page with the given |page_size|,
96  // |content_area| and  a |scale_factor| to use for the drawing. The units are
97  // in points (=1/72 in). Returns true on success.
98  virtual bool StartPage(const gfx::Size& page_size,
99                         const gfx::Rect& content_area,
100                         const float& scale_factor) = 0;
101
102  // Closes the current page and destroys the context used in rendering that
103  // page. The results of current page will be appended into the underlying
104  // data stream. Returns true on success.
105  virtual bool FinishPage() = 0;
106
107  // Closes the metafile. No further rendering is allowed (the current page
108  // is implicitly closed).
109  virtual bool FinishDocument() = 0;
110
111  // Returns the size of the underlying data stream. Only valid after Close()
112  // has been called.
113  virtual uint32 GetDataSize() const = 0;
114
115  // Copies the first |dst_buffer_size| bytes of the underlying data stream into
116  // |dst_buffer|. This function should ONLY be called after Close() is invoked.
117  // Returns true if the copy succeeds.
118  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const = 0;
119
120  // Saves the underlying data to the given file. This function should ONLY be
121  // called after the metafile is closed. Returns true if writing succeeded.
122  virtual bool SaveTo(const base::FilePath& file_path) const = 0;
123
124  // Returns the bounds of the given page. Pages use a 1-based index.
125  virtual gfx::Rect GetPageBounds(unsigned int page_number) const = 0;
126  virtual unsigned int GetPageCount() const = 0;
127
128  // Get the context for rendering to the PDF.
129  virtual gfx::NativeDrawingContext context() const = 0;
130
131#if defined(OS_WIN)
132  // "Plays" the EMF buffer in a HDC. It is the same effect as calling the
133  // original GDI function that were called when recording the EMF. |rect| is in
134  // "logical units" and is optional. If |rect| is NULL, the natural EMF bounds
135  // are used.
136  // Note: Windows has been known to have stack buffer overflow in its GDI
137  // functions, whether used directly or indirectly through precompiled EMF
138  // data. We have to accept the risk here. Since it is used only for printing,
139  // it requires user intervention.
140  virtual bool Playback(gfx::NativeDrawingContext hdc,
141                        const RECT* rect) const = 0;
142
143  // The slow version of Playback(). It enumerates all the records and play them
144  // back in the HDC. The trick is that it skip over the records known to have
145  // issue with some printers. See Emf::Record::SafePlayback implementation for
146  // details.
147  virtual bool SafePlayback(gfx::NativeDrawingContext hdc) const = 0;
148
149  virtual HENHMETAFILE emf() const = 0;
150#elif defined(OS_MACOSX)
151  // Renders the given page into |rect| in the given context.
152  // Pages use a 1-based index. The rendering uses the arguments in
153  // |params| to determine scaling, translation, and rotation.
154  virtual bool RenderPage(unsigned int page_number,
155                          gfx::NativeDrawingContext context,
156                          const CGRect rect,
157                          const MacRenderPageParams& params) const = 0;
158#elif defined(OS_CHROMEOS) || defined(OS_ANDROID)
159  // Saves the underlying data to the file associated with fd. This function
160  // should ONLY be called after the metafile is closed.
161  // Returns true if writing succeeded.
162  virtual bool SaveToFD(const base::FileDescriptor& fd) const = 0;
163#endif  // if defined(OS_CHROMEOS) || defined(OS_ANDROID)
164};
165
166}  // namespace printing
167
168#endif  // PRINTING_METAFILE_H_
169