ui/accelerated_widget_mac/display_link_mac.h

   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 #ifndef UI_ACCELERATED_WIDGET_MAC_DISPLAY_LINK_MAC_H_
   6 #define UI_ACCELERATED_WIDGET_MAC_DISPLAY_LINK_MAC_H_
   7
   8 #include <map>
   9 #include <QuartzCore/CVDisplayLink.h>
  10
  11 #include "base/lazy_instance.h"
  12 #include "base/mac/scoped_typeref.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/synchronization/lock.h"
  15 #include "base/time/time.h"
  16 #include "base/timer/timer.h"
  17 #include "ui/accelerated_widget_mac/accelerated_widget_mac_export.h"
  18
  19 namespace ui {
  20
  21 class ACCELERATED_WIDGET_MAC_EXPORT DisplayLinkMac :
  22     public base::RefCounted<DisplayLinkMac> {
  23  public:
  24   static scoped_refptr<DisplayLinkMac> GetForDisplay(
  25       CGDirectDisplayID display_id);
  26
  27   // Get vsync scheduling parameters.
  28   bool GetVSyncParameters(
  29       base::TimeTicks* timebase,
  30       base::TimeDelta* interval);
  31
  32   // The vsync parameters are cached, because re-computing them is expensive.
  33   // The parameters also skew over time (astonishingly quickly -- 0.1 msec per
  34   // second), so, use this method to tell the display link the current time.
  35   // If too much time has elapsed since the last time the vsync parameters were
  36   // calculated, re-calculate them.
  37   void NotifyCurrentTime(const base::TimeTicks& now);
  38
  39  private:
  40   friend class base::RefCounted<DisplayLinkMac>;
  41
  42   DisplayLinkMac(
  43       CGDirectDisplayID display_id,
  44       base::ScopedTypeRef<CVDisplayLinkRef> display_link);
  45   virtual ~DisplayLinkMac();
  46
  47   void StartOrContinueDisplayLink();
  48   void StopDisplayLink();
  49   void Tick(const CVTimeStamp& time);
  50
  51   // Called by the system on the display link thread, and posts a call to Tick
  52   // to the UI thread.
  53   static CVReturn DisplayLinkCallback(
  54       CVDisplayLinkRef display_link,
  55       const CVTimeStamp* now,
  56       const CVTimeStamp* output_time,
  57       CVOptionFlags flags_in,
  58       CVOptionFlags* flags_out,
  59       void* context);
  60
  61   // This is called whenever the display is reconfigured, and marks that the
  62   // vsync parameters must be recalculated.
  63   static void DisplayReconfigurationCallBack(
  64       CGDirectDisplayID display,
  65       CGDisplayChangeSummaryFlags flags,
  66       void* user_info);
  67
  68   // The task runner to post tasks to from the display link thread.
  69   scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
  70
  71   // The display that this display link is attached to.
  72   CGDirectDisplayID display_id_;
  73
  74   // CVDisplayLink for querying VSync timing info.
  75   base::ScopedTypeRef<CVDisplayLinkRef> display_link_;
  76
  77   // VSync parameters computed during Tick.
  78   bool timebase_and_interval_valid_;
  79   base::TimeTicks timebase_;
  80   base::TimeDelta interval_;
  81
  82   // The time after which we should re-start the display link to get fresh
  83   // parameters.
  84   base::TimeTicks recalculate_time_;
  85
  86   // Each display link instance consumes a non-negligible number of cycles, so
  87   // make all display links on the same screen share the same object.
  88   typedef std::map<CGDirectDisplayID, DisplayLinkMac*> DisplayMap;
  89   static base::LazyInstance<DisplayMap> display_map_;
  90 };
  91
  92 }  // ui
  93
  94 #endif  // UI_ACCELERATED_WIDGET_MAC_DISPLAY_LINK_MAC_H_