Connect the right metafiles for print preview on Linux and Windows.

printing/native_metafile.h

-// Copyright (c) 2011 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_NATIVE_METAFILE_H_
-#define PRINTING_NATIVE_METAFILE_H_
-
-#include "base/basictypes.h"
-#include "build/build_config.h"
-#include "ui/gfx/native_widget_types.h"
-
-#if defined(OS_WIN)
-#include <windows.h>
-#include <vector>
-#elif defined(OS_MACOSX)
-#include <ApplicationServices/ApplicationServices.h>
-#include <CoreFoundation/CoreFoundation.h>
-#include "base/mac/scoped_cftyperef.h"
-#endif
-
-class FilePath;
-
-namespace gfx {
-class Point;
-class Rect;
-class Size;
-}
-
-namespace skia {
-class PlatformDevice;
-}
-
-#if defined(OS_CHROMEOS)
-namespace base {
-class  FileDescriptor;
-}
-#endif
-
-namespace printing {
-
-// This class creates a graphics context that renders into a data stream
-// (usually PDF or EMF).
-class NativeMetafile {
- public:
-  virtual ~NativeMetafile() {}
-
-  // Initializes a fresh new metafile for rendering. Returns false on failure.
-  // Note: It should only be called from within the renderer process to allocate
-  // rendering resources.
-  virtual bool Init() = 0;
-
-  // Initializes the metafile with the data in |src_buffer|. Returns true
-  // on success.
-  // Note: It should only be called from within the browser process.
-  virtual bool InitFromData(const void* src_buffer, uint32 src_buffer_size) = 0;
-
-  // This method calls StartPage and then returns an appropriate
-  // VectorPlatformDevice implementation bound to the context created by
-  // StartPage or NULL on error.
-  virtual skia::PlatformDevice* StartPageForVectorCanvas(
-      const gfx::Size& page_size, const gfx::Point& content_origin,
-      const float& scale_factor) = 0;
-
-  // Prepares a context for rendering a new page at the specified
-  // |content_origin| with the given |page_size| and a |scale_factor| to use for
-  // the drawing. The units are in points (=1/72 in). Returns true on success.
-  virtual bool StartPage(const gfx::Size& page_size,
-                         const gfx::Point& content_origin,
-                         const float& scale_factor) = 0;
-
-  // Closes the current page and destroys the context used in rendering that
-  // page. The results of current page will be appended into the underlying
-  // data stream. Returns true on success.
-  virtual bool FinishPage() = 0;
-
-  // Closes the metafile. No further rendering is allowed (the current page
-  // is implicitly closed).
-  virtual bool FinishDocument() = 0;
-
-  // Returns the size of the underlying data stream. Only valid after Close()
-  // has been called.
-  virtual uint32 GetDataSize() const = 0;
-
-  // Copies the first |dst_buffer_size| bytes of the underlying data stream into
-  // |dst_buffer|. This function should ONLY be called after Close() is invoked.
-  // Returns true if the copy succeeds.
-  virtual bool GetData(void* dst_buffer, uint32 dst_buffer_size) const = 0;
-
-  // Saves the underlying data to the given file. This function should ONLY be
-  // called after the metafile is closed. Returns true if writing succeeded.
-  virtual bool SaveTo(const FilePath& file_path) const = 0;
-
-  // Returns the bounds of the given page. Pages use a 1-based index.
-  virtual gfx::Rect GetPageBounds(unsigned int page_number) const = 0;
-  virtual unsigned int GetPageCount() const = 0;
-
-  // Get the context for rendering to the PDF.
-  virtual gfx::NativeDrawingContext context() const = 0;
-
-#if defined(OS_WIN)
-  // "Plays" the EMF buffer in a HDC. It is the same effect as calling the
-  // original GDI function that were called when recording the EMF. |rect| is in
-  // "logical units" and is optional. If |rect| is NULL, the natural EMF bounds
-  // are used.
-  // Note: Windows has been known to have stack buffer overflow in its GDI
-  // functions, whether used directly or indirectly through precompiled EMF
-  // data. We have to accept the risk here. Since it is used only for printing,
-  // it requires user intervention.
-  virtual bool Playback(gfx::NativeDrawingContext hdc,
-                        const RECT* rect) const = 0;
-
-  // The slow version of Playback(). It enumerates all the records and play them
-  // back in the HDC. The trick is that it skip over the records known to have
-  // issue with some printers. See Emf::Record::SafePlayback implementation for
-  // details.
-  virtual bool SafePlayback(gfx::NativeDrawingContext hdc) const = 0;
-
-  virtual HENHMETAFILE emf() const = 0;
-#elif defined(OS_MACOSX)
-  // Renders the given page into |rect| in the given context.
-  // Pages use a 1-based index. The rendering uses the following arguments
-  // to determine scaling and translation factors.
-  // |shrink_to_fit| specifies whether the output should be shrunk to fit the
-  // supplied |rect| if the page size is larger than |rect| in any dimension.
-  // If this is false, parts of the PDF page that lie outside the bounds will be
-  // clipped.
-  // |stretch_to_fit| specifies whether the output should be stretched to fit
-  // the supplied bounds if the page size is smaller than |rect| in all
-  // dimensions.
-  // |center_horizontally| specifies whether the final image (after any scaling
-  // is done) should be centered horizontally within the given |rect|.
-  // |center_vertically| specifies whether the final image (after any scaling
-  // is done) should be centered vertically within the given |rect|.
-  // Note that all scaling preserves the original aspect ratio of the page.
-  virtual bool RenderPage(unsigned int page_number,
-                          gfx::NativeDrawingContext context,
-                          const CGRect rect,
-                          bool shrink_to_fit,
-                          bool stretch_to_fit,
-                          bool center_horizontally,
-                          bool center_vertically) const = 0;
-#elif defined(OS_CHROMEOS)
-  // Saves the underlying data to the file associated with fd. This function
-  // should ONLY be called after the metafile is closed.
-  // Returns true if writing succeeded.
-  virtual bool SaveToFD(const base::FileDescriptor& fd) const = 0;
-#endif  // if defined(OS_CHROMEOS)
-};
-
-}  // namespace printing
-
-#endif  // PRINTING_NATIVE_METAFILE_H_