chrome/browser/ui/panels/panel_mouse_watcher_timer.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 "base/time/time.h"
   6 #include "base/timer/timer.h"
   7 #include "chrome/browser/ui/panels/panel_mouse_watcher.h"
   8 #include "ui/gfx/screen.h"
   9
  10 // A timer based implementation of PanelMouseWatcher.  Currently used for Gtk
  11 // and Mac panels implementations.
  12 class PanelMouseWatcherTimer : public PanelMouseWatcher {
  13  public:
  14   PanelMouseWatcherTimer();
  15   virtual ~PanelMouseWatcherTimer();
  16
  17  private:
  18   virtual void Start() OVERRIDE;
  19   virtual void Stop() OVERRIDE;
  20   virtual bool IsActive() const OVERRIDE;
  21   virtual gfx::Point GetMousePosition() const OVERRIDE;
  22
  23   // Specifies the rate at which we want to sample the mouse position.
  24   static const int kMousePollingIntervalMs = 250;
  25
  26   // Timer callback function.
  27   void DoWork();
  28   friend class base::RepeatingTimer<PanelMouseWatcherTimer>;
  29
  30   // Timer used to track mouse movements. Some OSes do not provide an easy way
  31   // of tracking mouse movements across applications.  So we use a timer to
  32   // accomplish the same.  This could also be more efficient as you end up
  33   // getting a lot of notifications when tracking mouse movements.
  34   base::RepeatingTimer<PanelMouseWatcherTimer> timer_;
  35
  36   DISALLOW_COPY_AND_ASSIGN(PanelMouseWatcherTimer);
  37 };
  38
  39 // static
  40 PanelMouseWatcher* PanelMouseWatcher::Create() {
  41   return new PanelMouseWatcherTimer();
  42 }
  43
  44 PanelMouseWatcherTimer::PanelMouseWatcherTimer() {
  45 }
  46
  47 PanelMouseWatcherTimer::~PanelMouseWatcherTimer() {
  48   DCHECK(!IsActive());
  49 }
  50
  51 void PanelMouseWatcherTimer::Start() {
  52   DCHECK(!IsActive());
  53   timer_.Start(FROM_HERE,
  54                base::TimeDelta::FromMilliseconds(kMousePollingIntervalMs),
  55                this, &PanelMouseWatcherTimer::DoWork);
  56 }
  57
  58 void PanelMouseWatcherTimer::Stop() {
  59   DCHECK(IsActive());
  60   timer_.Stop();
  61 }
  62
  63 bool PanelMouseWatcherTimer::IsActive() const {
  64   return timer_.IsRunning();
  65 }
  66
  67 gfx::Point PanelMouseWatcherTimer::GetMousePosition() const {
  68   // TODO(scottmg): NativeScreen is wrong. http://crbug.com/133312
  69   return gfx::Screen::GetNativeScreen()->GetCursorScreenPoint();
  70 }
  71
  72 void PanelMouseWatcherTimer::DoWork() {
  73   NotifyMouseMovement(GetMousePosition());
  74 }