cc/output/software_output_device.h

   1 // Copyright 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 CC_OUTPUT_SOFTWARE_OUTPUT_DEVICE_H_
   6 #define CC_OUTPUT_SOFTWARE_OUTPUT_DEVICE_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "cc/base/cc_export.h"
  11 #include "skia/ext/refptr.h"
  12 #include "third_party/skia/include/core/SkSurface.h"
  13 #include "ui/gfx/geometry/rect.h"
  14 #include "ui/gfx/geometry/size.h"
  15 #include "ui/gfx/geometry/vector2d.h"
  16
  17 class SkBitmap;
  18 class SkCanvas;
  19
  20 namespace gfx {
  21 class VSyncProvider;
  22 }
  23
  24 namespace cc {
  25
  26 // This is a "tear-off" class providing software drawing support to
  27 // OutputSurface, such as to a platform-provided window framebuffer.
  28 class CC_EXPORT SoftwareOutputDevice {
  29  public:
  30   SoftwareOutputDevice();
  31   virtual ~SoftwareOutputDevice();
  32
  33   // Discards any pre-existing backing buffers and allocates memory for a
  34   // software device of |size|. This must be called before the
  35   // |SoftwareOutputDevice| can be used in other ways.
  36   virtual void Resize(const gfx::Size& pixel_size, float scale_factor);
  37
  38   // Called on BeginDrawingFrame. The compositor will draw into the returned
  39   // SkCanvas. The |SoftwareOutputDevice| implementation needs to provide a
  40   // valid SkCanvas of at least size |damage_rect|. This class retains ownership
  41   // of the SkCanvas.
  42   virtual SkCanvas* BeginPaint(const gfx::Rect& damage_rect);
  43
  44   // Called on FinishDrawingFrame. The compositor will no longer mutate the the
  45   // SkCanvas instance returned by |BeginPaint| and should discard any reference
  46   // that it holds to it.
  47   virtual void EndPaint();
  48
  49   // Discard the backing buffer in the surface provided by this instance.
  50   virtual void DiscardBackbuffer() {}
  51
  52   // Ensures that there is a backing buffer available on this instance.
  53   virtual void EnsureBackbuffer() {}
  54
  55   // VSyncProvider used to update the timer used to schedule draws with the
  56   // hardware vsync. Return NULL if a provider doesn't exist.
  57   virtual gfx::VSyncProvider* GetVSyncProvider();
  58
  59  protected:
  60   gfx::Size viewport_pixel_size_;
  61   float scale_factor_;
  62   gfx::Rect damage_rect_;
  63   skia::RefPtr<SkSurface> surface_;
  64   scoped_ptr<gfx::VSyncProvider> vsync_provider_;
  65
  66  private:
  67   DISALLOW_COPY_AND_ASSIGN(SoftwareOutputDevice);
  68 };
  69
  70 }  // namespace cc
  71
  72 #endif  // CC_OUTPUT_SOFTWARE_OUTPUT_DEVICE_H_