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 "base/json/json_writer.h"
6 #include "cc/output/begin_frame_args.h"
7 #include "ui/gfx/frame_time.h"
8
9 namespace cc {
10
BeginFrameArgs()11 BeginFrameArgs::BeginFrameArgs()
12 : frame_time(base::TimeTicks()),
13 deadline(base::TimeTicks()),
14 interval(base::TimeDelta::FromMicroseconds(-1)) {
15 }
16
BeginFrameArgs(base::TimeTicks frame_time,base::TimeTicks deadline,base::TimeDelta interval)17 BeginFrameArgs::BeginFrameArgs(base::TimeTicks frame_time,
18 base::TimeTicks deadline,
19 base::TimeDelta interval)
20 : frame_time(frame_time),
21 deadline(deadline),
22 interval(interval)
23 {}
24
Create(base::TimeTicks frame_time,base::TimeTicks deadline,base::TimeDelta interval)25 BeginFrameArgs BeginFrameArgs::Create(base::TimeTicks frame_time,
26 base::TimeTicks deadline,
27 base::TimeDelta interval) {
28 return BeginFrameArgs(frame_time, deadline, interval);
29 }
30
AsValue() const31 scoped_ptr<base::Value> BeginFrameArgs::AsValue() const {
32 scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue);
33 state->SetString("type", "BeginFrameArgs");
34 state->SetDouble("frame_time_us", frame_time.ToInternalValue());
35 state->SetDouble("deadline_us", deadline.ToInternalValue());
36 state->SetDouble("interval_us", interval.InMicroseconds());
37 return state.PassAs<base::Value>();
38 }
39
CreateForSynchronousCompositor(base::TimeTicks now)40 BeginFrameArgs BeginFrameArgs::CreateForSynchronousCompositor(
41 base::TimeTicks now) {
42 // For WebView/SynchronousCompositor, we always want to draw immediately,
43 // so we set the deadline to 0 and guess that the interval is 16 milliseconds.
44 if (now.is_null())
45 now = gfx::FrameTime::Now();
46 return BeginFrameArgs(now, base::TimeTicks(), DefaultInterval());
47 }
48
49 // This is a hard-coded deadline adjustment that assumes 60Hz, to be used in
50 // cases where a good estimated draw time is not known. Using 1/3 of the vsync
51 // as the default adjustment gives the Browser the last 1/3 of a frame to
52 // produce output, the Renderer Impl thread the middle 1/3 of a frame to produce
53 // ouput, and the Renderer Main thread the first 1/3 of a frame to produce
54 // output.
DefaultEstimatedParentDrawTime()55 base::TimeDelta BeginFrameArgs::DefaultEstimatedParentDrawTime() {
56 return base::TimeDelta::FromMicroseconds(16666 / 3);
57 }
58
DefaultInterval()59 base::TimeDelta BeginFrameArgs::DefaultInterval() {
60 return base::TimeDelta::FromMicroseconds(16666);
61 }
62
DefaultRetroactiveBeginFramePeriod()63 base::TimeDelta BeginFrameArgs::DefaultRetroactiveBeginFramePeriod() {
64 return base::TimeDelta::FromMicroseconds(4444);
65 }
66
67 } // namespace cc
68