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 #include "base/debug/trace_event_argument.h"
   8 #include "ui/gfx/frame_time.h"
   9
  10 namespace cc {
  11
  12 BeginFrameArgs::BeginFrameArgs()
  13   : frame_time(base::TimeTicks()),
  14     deadline(base::TimeTicks()),
  15     interval(base::TimeDelta::FromMicroseconds(-1)) {
  16 }
  17
  18 BeginFrameArgs::BeginFrameArgs(base::TimeTicks frame_time,
  19                                base::TimeTicks deadline,
  20                                base::TimeDelta interval)
  21   : frame_time(frame_time),
  22     deadline(deadline),
  23     interval(interval)
  24 {}
  25
  26 BeginFrameArgs BeginFrameArgs::Create(base::TimeTicks frame_time,
  27                                       base::TimeTicks deadline,
  28                                       base::TimeDelta interval) {
  29   return BeginFrameArgs(frame_time, deadline, interval);
  30 }
  31
  32 scoped_refptr<base::debug::ConvertableToTraceFormat> BeginFrameArgs::AsValue()
  33     const {
  34   scoped_refptr<base::debug::TracedValue> state =
  35       new base::debug::TracedValue();
  36   AsValueInto(state.get());
  37   return state;
  38 }
  39
  40 void BeginFrameArgs::AsValueInto(base::debug::TracedValue* state) const {
  41   state->SetString("type", "BeginFrameArgs");
  42   state->SetDouble("frame_time_us", frame_time.ToInternalValue());
  43   state->SetDouble("deadline_us", deadline.ToInternalValue());
  44   state->SetDouble("interval_us", interval.InMicroseconds());
  45 }
  46
  47 BeginFrameArgs BeginFrameArgs::CreateForSynchronousCompositor(
  48     base::TimeTicks now) {
  49   // For WebView/SynchronousCompositor, we always want to draw immediately,
  50   // so we set the deadline to 0 and guess that the interval is 16 milliseconds.
  51   if (now.is_null())
  52     now = gfx::FrameTime::Now();
  53   return BeginFrameArgs(now, base::TimeTicks(), DefaultInterval());
  54 }
  55
  56 // This is a hard-coded deadline adjustment that assumes 60Hz, to be used in
  57 // cases where a good estimated draw time is not known. Using 1/3 of the vsync
  58 // as the default adjustment gives the Browser the last 1/3 of a frame to
  59 // produce output, the Renderer Impl thread the middle 1/3 of a frame to produce
  60 // ouput, and the Renderer Main thread the first 1/3 of a frame to produce
  61 // output.
  62 base::TimeDelta BeginFrameArgs::DefaultEstimatedParentDrawTime() {
  63   return base::TimeDelta::FromMicroseconds(16666 / 3);
  64 }
  65
  66 base::TimeDelta BeginFrameArgs::DefaultInterval() {
  67   return base::TimeDelta::FromMicroseconds(16666);
  68 }
  69
  70 base::TimeDelta BeginFrameArgs::DefaultRetroactiveBeginFramePeriod() {
  71   return base::TimeDelta::FromMicroseconds(4444);
  72 }
  73
  74 }  // namespace cc