1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2  *
3  * This Source Code Form is subject to the terms of the Mozilla Public
4  * License, v. 2.0. If a copy of the MPL was not distributed with this
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 #ifndef _MOZILLA_WIDGET_WINDOW_SURFACE_H
8 #define _MOZILLA_WIDGET_WINDOW_SURFACE_H
9 
10 #include "mozilla/gfx/2D.h"
11 #include "Units.h"
12 
13 namespace mozilla {
14 namespace widget {
15 
16 // A class for drawing to double-buffered windows.
17 class WindowSurface {
18  public:
19   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WindowSurface);
20 
21   // Locks a region of the window for drawing, returning a draw target
22   // capturing the bounds of the provided region.
23   // Implementations must permit invocation from any thread.
24   virtual already_AddRefed<gfx::DrawTarget> Lock(
25       const LayoutDeviceIntRegion& aRegion) = 0;
26 
27   // Swaps the provided invalid region from the back buffer to the window.
28   // Implementations must permit invocation from any thread.
29   virtual void Commit(const LayoutDeviceIntRegion& aInvalidRegion) = 0;
30 
31   // Whether the window surface represents a fallback method.
IsFallback()32   virtual bool IsFallback() const { return false; }
33 
34  protected:
35   virtual ~WindowSurface() = default;
36 };
37 
38 }  // namespace widget
39 }  // namespace mozilla
40 
41 #endif  // _MOZILLA_WIDGET_WINDOW_SURFACE_H
42