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 ASH_WM_SCREEN_DIMMER_H_ 6 #define ASH_WM_SCREEN_DIMMER_H_ 7 8 #include "ash/ash_export.h" 9 #include "base/basictypes.h" 10 #include "base/compiler_specific.h" 11 #include "base/memory/scoped_ptr.h" 12 #include "ui/aura/window_observer.h" 13 14 namespace ui { 15 class Layer; 16 } 17 18 namespace ash { 19 20 // ScreenDimmer displays a partially-opaque layer above everything 21 // else in the root window to darken the display. It shouldn't be used 22 // for long-term brightness adjustments due to performance 23 // considerations -- it's only intended for cases where we want to 24 // briefly dim the screen (e.g. to indicate to the user that we're 25 // about to suspend a machine that lacks an internal backlight that 26 // can be adjusted). 27 class ASH_EXPORT ScreenDimmer : public aura::WindowObserver { 28 public: 29 class TestApi { 30 public: TestApi(ScreenDimmer * dimmer)31 explicit TestApi(ScreenDimmer* dimmer) : dimmer_(dimmer) {} 32 layer()33 ui::Layer* layer() { return dimmer_->dimming_layer_.get(); } 34 35 private: 36 ScreenDimmer* dimmer_; // not owned 37 38 DISALLOW_COPY_AND_ASSIGN(TestApi); 39 }; 40 41 explicit ScreenDimmer(aura::Window* root_window); 42 virtual ~ScreenDimmer(); 43 44 // Dim or undim the root window. 45 void SetDimming(bool should_dim); 46 47 // aura::WindowObserver overrides: 48 virtual void OnWindowBoundsChanged(aura::Window* root_window, 49 const gfx::Rect& old_bounds, 50 const gfx::Rect& new_bounds) OVERRIDE; 51 52 private: 53 friend class TestApi; 54 55 aura::Window* root_window_; 56 57 // Partially-opaque layer that's stacked above all of the root window's 58 // children and used to dim the screen. NULL until the first time we dim. 59 scoped_ptr<ui::Layer> dimming_layer_; 60 61 // Are we currently dimming the screen? 62 bool currently_dimming_; 63 64 DISALLOW_COPY_AND_ASSIGN(ScreenDimmer); 65 }; 66 67 } // namespace ash 68 69 #endif // ASH_WM_SCREEN_DIMMER_H_ 70