ash/utility/partial_screenshot_controller.cc

   1 // Copyright 2014 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/utility/partial_screenshot_controller.h"
   6
   7 #include <cmath>
   8
   9 #include "ash/screenshot_delegate.h"
  10 #include "ash/shell.h"
  11 #include "ash/shell_window_ids.h"
  12 #include "base/stl_util.h"
  13 #include "ui/events/event_handler.h"
  14 #include "ui/gfx/canvas.h"
  15 #include "ui/wm/core/cursor_manager.h"
  16
  17 namespace ash {
  18
  19 namespace {
  20
  21 PartialScreenshotController* instance = nullptr;
  22
  23 // The size to increase the invalidated area in the layer to repaint. The area
  24 // should be slightly bigger than the actual region because the region indicator
  25 // rectangles are drawn outside of the selected region.
  26 const int kInvalidateRegionAdditionalSize = 3;
  27
  28 }  // namespace
  29
  30 class PartialScreenshotController::PartialScreenshotLayer
  31     : public ui::LayerOwner,
  32       public ui::LayerDelegate {
  33  public:
  34   PartialScreenshotLayer(ui::Layer* parent) {
  35     SetLayer(new ui::Layer(ui::LAYER_TEXTURED));
  36     layer()->SetFillsBoundsOpaquely(false);
  37     layer()->SetBounds(parent->bounds());
  38     parent->Add(layer());
  39     parent->StackAtTop(layer());
  40     layer()->SetVisible(true);
  41     layer()->set_delegate(this);
  42   }
  43   ~PartialScreenshotLayer() override {}
  44
  45   const gfx::Rect& region() const { return region_; }
  46
  47   void SetRegion(const gfx::Rect& region) {
  48     // Invalidates the region which covers the current and new region.
  49     gfx::Rect union_rect(region_);
  50     union_rect.Union(region);
  51     union_rect.Inset(-kInvalidateRegionAdditionalSize,
  52                      -kInvalidateRegionAdditionalSize);
  53     union_rect.Intersects(layer()->bounds());
  54
  55     region_ = region;
  56     layer()->SchedulePaint(union_rect);
  57   }
  58
  59  private:
  60   // ui::LayerDelegate:
  61   void OnPaintLayer(gfx::Canvas* canvas) override {
  62     if (region_.IsEmpty())
  63       return;
  64
  65     // Screenshot area representation: black rectangle with white
  66     // rectangle inside.  To avoid capturing these rectangles when mouse
  67     // release, they should be outside of the actual capturing area.
  68     gfx::Rect rect(region_);
  69     rect.Inset(-1, -1);
  70     canvas->DrawRect(rect, SK_ColorWHITE);
  71     rect.Inset(-1, -1);
  72     canvas->DrawRect(rect, SK_ColorBLACK);
  73   }
  74
  75   void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override {}
  76
  77   void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
  78
  79   base::Closure PrepareForLayerBoundsChange() override {
  80     return base::Closure();
  81   }
  82
  83   gfx::Rect region_;
  84
  85   DISALLOW_COPY_AND_ASSIGN(PartialScreenshotLayer);
  86 };
  87
  88 class PartialScreenshotController::ScopedCursorSetter {
  89  public:
  90   ScopedCursorSetter(::wm::CursorManager* cursor_manager,
  91                      gfx::NativeCursor cursor)
  92       : cursor_manager_(nullptr) {
  93     if (cursor_manager->IsCursorLocked())
  94       return;
  95     gfx::NativeCursor original_cursor = cursor_manager->GetCursor();
  96     cursor_manager_ = cursor_manager;
  97     cursor_manager_->SetCursor(cursor);
  98     cursor_manager_->LockCursor();
  99     // SetCursor does not make any effects at this point but it sets back to the
 100     // original cursor when unlocked.
 101     cursor_manager_->SetCursor(original_cursor);
 102   }
 103
 104   ~ScopedCursorSetter() {
 105     if (cursor_manager_)
 106       cursor_manager_->UnlockCursor();
 107   }
 108
 109  private:
 110   ::wm::CursorManager* cursor_manager_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(ScopedCursorSetter);
 113 };
 114
 115 // static
 116 void PartialScreenshotController::StartPartialScreenshotSession(
 117     ScreenshotDelegate* screenshot_delegate) {
 118   // Already in the session.
 119   if (instance)
 120     return;
 121   instance = new PartialScreenshotController(screenshot_delegate);
 122 }
 123
 124 // static
 125 PartialScreenshotController* PartialScreenshotController::GetInstanceForTest() {
 126   return instance;
 127 }
 128
 129 PartialScreenshotController::PartialScreenshotController(
 130     ScreenshotDelegate* screenshot_delegate)
 131     : root_window_(nullptr), screenshot_delegate_(screenshot_delegate) {
 132   DCHECK(screenshot_delegate_);
 133   Shell* shell = Shell::GetInstance();
 134   shell->PrependPreTargetHandler(this);
 135   shell->AddShellObserver(this);
 136   Shell::GetScreen()->AddObserver(this);
 137
 138   for (aura::Window* root : Shell::GetAllRootWindows()) {
 139     layers_[root] = new PartialScreenshotLayer(
 140         Shell::GetContainer(root, kShellWindowId_OverlayContainer)->layer());
 141   }
 142
 143   cursor_setter_.reset(
 144       new ScopedCursorSetter(shell->cursor_manager(), ui::kCursorCross));
 145 }
 146
 147 PartialScreenshotController::~PartialScreenshotController() {
 148   DCHECK_EQ(this, instance);
 149   instance = nullptr;
 150
 151   Shell::GetScreen()->RemoveObserver(this);
 152   Shell::GetInstance()->RemovePreTargetHandler(this);
 153   Shell::GetInstance()->RemoveShellObserver(this);
 154   STLDeleteValues(&layers_);
 155 }
 156
 157 void PartialScreenshotController::MaybeStart(const ui::LocatedEvent& event) {
 158   aura::Window* current_root =
 159       static_cast<aura::Window*>(event.target())->GetRootWindow();
 160   if (root_window_) {
 161     // It's already started. This can happen when the second finger touches
 162     // the screen, or combination of the touch and mouse. We should grab the
 163     // partial screenshot instead of restarting.
 164     if (current_root == root_window_) {
 165       Update(event);
 166       Complete();
 167     }
 168   } else {
 169     root_window_ = current_root;
 170     start_position_ = event.root_location();
 171   }
 172 }
 173
 174 void PartialScreenshotController::Complete() {
 175   const gfx::Rect& region = layers_[root_window_]->region();
 176   if (!region.IsEmpty()) {
 177     screenshot_delegate_->HandleTakePartialScreenshot(
 178         root_window_, gfx::IntersectRects(root_window_->bounds(), region));
 179   }
 180   Cancel();
 181 }
 182
 183 void PartialScreenshotController::Cancel() {
 184   delete this;
 185 }
 186
 187 void PartialScreenshotController::Update(const ui::LocatedEvent& event) {
 188   // Update may happen without MaybeStart() if the partial screenshot session
 189   // starts when dragging.
 190   if (!root_window_)
 191     MaybeStart(event);
 192
 193   DCHECK(layers_.find(root_window_) != layers_.end());
 194   layers_[root_window_]->SetRegion(
 195       gfx::Rect(std::min(start_position_.x(), event.root_location().x()),
 196                 std::min(start_position_.y(), event.root_location().y()),
 197                 ::abs(start_position_.x() - event.root_location().x()),
 198                 ::abs(start_position_.y() - event.root_location().y())));
 199 }
 200
 201 void PartialScreenshotController::OnKeyEvent(ui::KeyEvent* event) {
 202   if (event->type() == ui::ET_KEY_RELEASED &&
 203       event->key_code() == ui::VKEY_ESCAPE) {
 204     Cancel();
 205   }
 206
 207   // Intercepts all key events.
 208   event->StopPropagation();
 209 }
 210
 211 void PartialScreenshotController::OnMouseEvent(ui::MouseEvent* event) {
 212   switch (event->type()) {
 213     case ui::ET_MOUSE_PRESSED:
 214       MaybeStart(*event);
 215       break;
 216     case ui::ET_MOUSE_DRAGGED:
 217       Update(*event);
 218       break;
 219     case ui::ET_MOUSE_RELEASED:
 220       Complete();
 221       break;
 222     default:
 223       // Do nothing.
 224       break;
 225   }
 226   event->StopPropagation();
 227 }
 228
 229 void PartialScreenshotController::OnTouchEvent(ui::TouchEvent* event) {
 230   switch (event->type()) {
 231     case ui::ET_TOUCH_PRESSED:
 232       MaybeStart(*event);
 233       break;
 234     case ui::ET_TOUCH_MOVED:
 235       Update(*event);
 236       break;
 237     case ui::ET_TOUCH_RELEASED:
 238       Complete();
 239       break;
 240     default:
 241       // Do nothing.
 242       break;
 243   }
 244   event->StopPropagation();
 245 }
 246
 247 void PartialScreenshotController::OnAppTerminating() {
 248   Cancel();
 249 }
 250
 251 void PartialScreenshotController::OnDisplayAdded(
 252     const gfx::Display& new_display) {
 253   Cancel();
 254 }
 255
 256 void PartialScreenshotController::OnDisplayRemoved(
 257     const gfx::Display& old_display) {
 258   Cancel();
 259 }
 260
 261 void PartialScreenshotController::OnDisplayMetricsChanged(
 262     const gfx::Display& display,
 263     uint32_t changed_metrics) {
 264 }
 265
 266 }  // namespace ash