ash/wm/screen_dimmer.cc

   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 #include "ash/wm/screen_dimmer.h"
   6
   7 #include "ash/shell.h"
   8 #include "base/time.h"
   9 #include "ui/aura/root_window.h"
  10 #include "ui/compositor/layer.h"
  11 #include "ui/compositor/scoped_layer_animation_settings.h"
  12 #include "ui/gfx/rect.h"
  13 #include "ui/gfx/size.h"
  14
  15 namespace ash {
  16 namespace internal {
  17
  18 namespace {
  19
  20 // Opacity for |dimming_layer_| when it's dimming the screen.
  21 const float kDimmingLayerOpacity = 0.4f;
  22
  23 // Duration for dimming animations, in milliseconds.
  24 const int kDimmingTransitionMs = 200;
  25
  26 }  // namespace
  27
  28 ScreenDimmer::ScreenDimmer(aura::RootWindow* root_window)
  29     : root_window_(root_window),
  30       currently_dimming_(false) {
  31   root_window_->AddRootWindowObserver(this);
  32 }
  33
  34 ScreenDimmer::~ScreenDimmer() {
  35   root_window_->RemoveRootWindowObserver(this);
  36 }
  37
  38 void ScreenDimmer::SetDimming(bool should_dim) {
  39   if (should_dim == currently_dimming_)
  40     return;
  41
  42   if (!dimming_layer_) {
  43     dimming_layer_.reset(new ui::Layer(ui::LAYER_SOLID_COLOR));
  44     dimming_layer_->SetColor(SK_ColorBLACK);
  45     dimming_layer_->SetOpacity(0.0f);
  46     ui::Layer* root_layer = root_window_->layer();
  47     dimming_layer_->SetBounds(root_layer->bounds());
  48     root_layer->Add(dimming_layer_.get());
  49     root_layer->StackAtTop(dimming_layer_.get());
  50   }
  51
  52   currently_dimming_ = should_dim;
  53
  54   ui::ScopedLayerAnimationSettings scoped_settings(
  55       dimming_layer_->GetAnimator());
  56   scoped_settings.SetTransitionDuration(
  57       base::TimeDelta::FromMilliseconds(kDimmingTransitionMs));
  58   dimming_layer_->SetOpacity(should_dim ? kDimmingLayerOpacity : 0.0f);
  59 }
  60
  61 void ScreenDimmer::OnRootWindowResized(const aura::RootWindow* root,
  62                                        const gfx::Size& old_size) {
  63   if (dimming_layer_)
  64     dimming_layer_->SetBounds(gfx::Rect(root->bounds().size()));
  65 }
  66
  67 }  // namespace internal
  68 }  // namespace ash