gfx/layers/apz/src/PotentialCheckerboardDurationTracker.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_layers_PotentialCheckerboardDurationTracker_h
   8 #define mozilla_layers_PotentialCheckerboardDurationTracker_h
   9
  10 #include "mozilla/TimeStamp.h"
  11
  12 namespace mozilla {
  13 namespace layers {
  14
  15 /**
  16  * This class allows the owner to track the duration of time considered
  17  * "potentially checkerboarding". This is the union of two possibly-intersecting
  18  * sets of time periods. The first set is that in which checkerboarding was
  19  * actually happening, since by definition it could potentially be happening.
  20  * The second set is that in which the APZC is actively transforming content
  21  * in the compositor, since it could potentially transform it so as to display
  22  * checkerboarding to the user.
  23  * The caller of this class calls the appropriate methods to indicate the start
  24  * and stop of these two sets, and this class manages accumulating the union
  25  * of the various durations.
  26  */
  27 class PotentialCheckerboardDurationTracker {
  28  public:
  29   PotentialCheckerboardDurationTracker();
  30
  31   /**
  32    * This should be called if checkerboarding is encountered. It can be called
  33    * multiple times during a checkerboard event.
  34    */
  35   void CheckerboardSeen();
  36   /**
  37    * This should be called when checkerboarding is done. It must have been
  38    * preceded by one or more calls to CheckerboardSeen().
  39    */
  40   void CheckerboardDone(bool aRecordTelemetry);
  41
  42   /**
  43    * This should be called at composition time, to indicate if the APZC is in
  44    * a transforming state or not.
  45    */
  46   void InTransform(bool aInTransform, bool aRecordTelemetry);
  47
  48  private:
  49   bool Tracking() const;
  50
  51  private:
  52   bool mInCheckerboard;
  53   bool mInTransform;
  54
  55   TimeStamp mCurrentPeriodStart;
  56 };
  57
  58 }  // namespace layers
  59 }  // namespace mozilla
  60
  61 #endif  // mozilla_layers_PotentialCheckerboardDurationTracker_h