cc/output/begin_frame_args.cc

   1 // Copyright 2013 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 "cc/output/begin_frame_args.h"
   6
   7 namespace cc {
   8
   9 BeginFrameArgs::BeginFrameArgs()
  10   : frame_time(base::TimeTicks()),
  11     deadline(base::TimeTicks()),
  12     interval(base::TimeDelta::FromMicroseconds(-1)) {
  13 }
  14
  15 BeginFrameArgs::BeginFrameArgs(base::TimeTicks frame_time,
  16                                base::TimeTicks deadline,
  17                                base::TimeDelta interval)
  18   : frame_time(frame_time),
  19     deadline(deadline),
  20     interval(interval)
  21 {}
  22
  23 BeginFrameArgs BeginFrameArgs::Create(base::TimeTicks frame_time,
  24                                       base::TimeTicks deadline,
  25                                       base::TimeDelta interval) {
  26   return BeginFrameArgs(frame_time, deadline, interval);
  27 }
  28
  29 BeginFrameArgs BeginFrameArgs::CreateForSynchronousCompositor() {
  30   // For WebView/SynchronousCompositor, we always want to draw immediately,
  31   // so we set the deadline to 0 and guess that the interval is 16 milliseconds.
  32   return BeginFrameArgs(base::TimeTicks::Now(),
  33                         base::TimeTicks(),
  34                         DefaultInterval());
  35 }
  36
  37 BeginFrameArgs BeginFrameArgs::CreateForTesting() {
  38   base::TimeTicks now = base::TimeTicks::Now();
  39   return BeginFrameArgs(now,
  40                         now + (DefaultInterval() / 2),
  41                         DefaultInterval());
  42 }
  43
  44 BeginFrameArgs BeginFrameArgs::CreateExpiredForTesting() {
  45   base::TimeTicks now = base::TimeTicks::Now();
  46   return BeginFrameArgs(now,
  47                         now - DefaultInterval(),
  48                         DefaultInterval());
  49 }
  50
  51 // This is a hard-coded deadline adjustment that assumes 60Hz, to be used in
  52 // cases where a good estimated draw time is not known. Using 1/3 of the vsync
  53 // as the default adjustment gives the Browser the last 1/3 of a frame to
  54 // produce output, the Renderer Impl thread the middle 1/3 of a frame to produce
  55 // ouput, and the Renderer Main thread the first 1/3 of a frame to produce
  56 // output.
  57 base::TimeDelta BeginFrameArgs::DefaultDeadlineAdjustment() {
  58   return base::TimeDelta::FromMicroseconds(-16666 / 3);
  59 }
  60
  61 base::TimeDelta BeginFrameArgs::DefaultInterval() {
  62   return base::TimeDelta::FromMicroseconds(16666);
  63 }
  64
  65 base::TimeDelta BeginFrameArgs::DefaultRetroactiveBeginFramePeriod() {
  66   return base::TimeDelta::FromMicroseconds(4444);
  67 }
  68
  69 }  // namespace cc