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// Copyright (c) 2012 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 ASH_WM_SCREEN_DIMMER_H_
#define ASH_WM_SCREEN_DIMMER_H_
#include "ash/ash_export.h"
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/memory/scoped_ptr.h"
#include "ui/aura/root_window_observer.h"
namespace aura {
class RootWindow;
}
namespace ui {
class Layer;
}
namespace ash {
namespace internal {
// ScreenDimmer displays a partially-opaque layer above everything
// else in the root window to darken the display. It shouldn't be used
// for long-term brightness adjustments due to performance
// considerations -- it's only intended for cases where we want to
// briefly dim the screen (e.g. to indicate to the user that we're
// about to suspend a machine that lacks an internal backlight that
// can be adjusted).
class ASH_EXPORT ScreenDimmer : public aura::RootWindowObserver {
public:
class TestApi {
public:
explicit TestApi(ScreenDimmer* dimmer) : dimmer_(dimmer) {}
ui::Layer* layer() { return dimmer_->dimming_layer_.get(); }
private:
ScreenDimmer* dimmer_; // not owned
DISALLOW_COPY_AND_ASSIGN(TestApi);
};
explicit ScreenDimmer(aura::RootWindow* root_window);
virtual ~ScreenDimmer();
// Dim or undim the root window.
void SetDimming(bool should_dim);
// aura::RootWindowObserver overrides:
virtual void OnRootWindowResized(const aura::RootWindow* root,
const gfx::Size& old_size) OVERRIDE;
private:
friend class TestApi;
aura::RootWindow* root_window_;
// Partially-opaque layer that's stacked above all of the root window's
// children and used to dim the screen. NULL until the first time we dim.
scoped_ptr<ui::Layer> dimming_layer_;
// Are we currently dimming the screen?
bool currently_dimming_;
DISALLOW_COPY_AND_ASSIGN(ScreenDimmer);
};
} // namespace internal
} // namespace ash
#endif // ASH_WM_SCREEN_DIMMER_H_