content/browser/renderer_host/backing_store.h

   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 CONTENT_BROWSER_RENDERER_HOST_BACKING_STORE_H_
   6 #define CONTENT_BROWSER_RENDERER_HOST_BACKING_STORE_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback_forward.h"
  12 #include "content/common/content_export.h"
  13 #include "ui/gfx/size.h"
  14 #include "ui/gfx/vector2d.h"
  15 #include "ui/surface/transport_dib.h"
  16
  17 class RenderProcessHost;
  18
  19 namespace gfx {
  20 class Rect;
  21 }
  22
  23 namespace skia {
  24 class PlatformBitmap;
  25 }
  26
  27 namespace content {
  28 class RenderProcessHost;
  29 class RenderWidgetHost;
  30
  31 // Represents a backing store for the pixels in a RenderWidgetHost.
  32 class CONTENT_EXPORT BackingStore {
  33  public:
  34   virtual ~BackingStore();
  35
  36   RenderWidgetHost* render_widget_host() const {
  37     return render_widget_host_;
  38   }
  39   const gfx::Size& size() { return size_; }
  40
  41   // The number of bytes that this backing store consumes. The default
  42   // implementation just assumes there's 32 bits per pixel over the current
  43   // size of the screen. Implementations may override this if they have more
  44   // information about the color depth.
  45   virtual size_t MemorySize();
  46
  47   // Paints the bitmap from the renderer onto the backing store. bitmap_rect
  48   // gives the location of bitmap, and copy_rects specifies the subregion(s) of
  49   // the backingstore to be painted from the bitmap. All coordinates are in
  50   // DIPs. |scale_factor| contains the expected device scale factor of the
  51   // backing store.
  52   //
  53   // PaintToBackingStore does not need to guarantee that this has happened by
  54   // the time it returns, in which case it will set |scheduled_callback| to
  55   // true and will call |callback| when completed.
  56   virtual void PaintToBackingStore(
  57       RenderProcessHost* process,
  58       TransportDIB::Id bitmap,
  59       const gfx::Rect& bitmap_rect,
  60       const std::vector<gfx::Rect>& copy_rects,
  61       float scale_factor,
  62       const base::Closure& completion_callback,
  63       bool* scheduled_completion_callback) = 0;
  64
  65   // Extracts the gives subset of the backing store and copies it to the given
  66   // PlatformCanvas. The PlatformCanvas should not be initialized. This function
  67   // will call initialize() with the correct size. The return value indicates
  68   // success.
  69   virtual bool CopyFromBackingStore(const gfx::Rect& rect,
  70                                     skia::PlatformBitmap* output) = 0;
  71
  72   // Scrolls the contents of clip_rect in the backing store by |delta| (but
  73   // |delta|.x() and |delta|.y() cannot both be non-zero).
  74   virtual void ScrollBackingStore(const gfx::Vector2d& delta,
  75                                   const gfx::Rect& clip_rect,
  76                                   const gfx::Size& view_size) = 0;
  77  protected:
  78   // Can only be constructed via subclasses.
  79   BackingStore(RenderWidgetHost* widget, const gfx::Size& size);
  80
  81  private:
  82   // The owner of this backing store.
  83   RenderWidgetHost* render_widget_host_;
  84
  85   // The size of the backing store.
  86   gfx::Size size_;
  87
  88   DISALLOW_COPY_AND_ASSIGN(BackingStore);
  89 };
  90
  91 }  // namespace content
  92
  93 #endif  // CONTENT_BROWSER_RENDERER_HOST_BACKING_STORE_H_