Home | History | Annotate | Download | only in output 
      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
     75