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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/renderer_host/input/synthetic_pinch_gesture.h"
#include <cmath>
#include "base/logging.h"
#include "ui/events/latency_info.h"
namespace content {
SyntheticPinchGesture::SyntheticPinchGesture(
const SyntheticPinchGestureParams& params)
: params_(params),
start_y_0_(0.0f),
start_y_1_(0.0f),
max_pointer_delta_0_(0.0f),
gesture_source_type_(SyntheticGestureParams::DEFAULT_INPUT),
state_(SETUP) {
DCHECK_GT(params_.scale_factor, 0.0f);
}
SyntheticPinchGesture::~SyntheticPinchGesture() {}
SyntheticGesture::Result SyntheticPinchGesture::ForwardInputEvents(
const base::TimeTicks& timestamp, SyntheticGestureTarget* target) {
if (state_ == SETUP) {
gesture_source_type_ = params_.gesture_source_type;
if (gesture_source_type_ == SyntheticGestureParams::DEFAULT_INPUT)
gesture_source_type_ = target->GetDefaultSyntheticGestureSourceType();
state_ = STARTED;
start_time_ = timestamp;
}
DCHECK_NE(gesture_source_type_, SyntheticGestureParams::DEFAULT_INPUT);
if (gesture_source_type_ == SyntheticGestureParams::TOUCH_INPUT)
ForwardTouchInputEvents(timestamp, target);
else
return SyntheticGesture::GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED;
return (state_ == DONE) ? SyntheticGesture::GESTURE_FINISHED
: SyntheticGesture::GESTURE_RUNNING;
}
void SyntheticPinchGesture::ForwardTouchInputEvents(
const base::TimeTicks& timestamp, SyntheticGestureTarget* target) {
switch (state_) {
case STARTED:
// Check for an early finish.
if (params_.scale_factor == 1.0f) {
state_ = DONE;
break;
}
SetupCoordinatesAndStopTime(target);
PressTouchPoints(target, timestamp);
state_ = MOVING;
break;
case MOVING: {
base::TimeTicks event_timestamp = ClampTimestamp(timestamp);
float delta = GetDeltaForPointer0AtTime(event_timestamp);
MoveTouchPoints(target, delta, event_timestamp);
if (HasReachedTarget(event_timestamp)) {
ReleaseTouchPoints(target, event_timestamp);
state_ = DONE;
}
} break;
case SETUP:
NOTREACHED() << "State SETUP invalid for synthetic pinch.";
case DONE:
NOTREACHED() << "State DONE invalid for synthetic pinch.";
}
}
void SyntheticPinchGesture::PressTouchPoints(SyntheticGestureTarget* target,
const base::TimeTicks& timestamp) {
touch_event_.PressPoint(params_.anchor.x(), start_y_0_);
touch_event_.PressPoint(params_.anchor.x(), start_y_1_);
ForwardTouchEvent(target, timestamp);
}
void SyntheticPinchGesture::MoveTouchPoints(SyntheticGestureTarget* target,
float delta,
const base::TimeTicks& timestamp) {
// The two pointers move in opposite directions.
float current_y_0 = start_y_0_ + delta;
float current_y_1 = start_y_1_ - delta;
touch_event_.MovePoint(0, params_.anchor.x(), current_y_0);
touch_event_.MovePoint(1, params_.anchor.x(), current_y_1);
ForwardTouchEvent(target, timestamp);
}
void SyntheticPinchGesture::ReleaseTouchPoints(
SyntheticGestureTarget* target, const base::TimeTicks& timestamp) {
touch_event_.ReleasePoint(0);
touch_event_.ReleasePoint(1);
ForwardTouchEvent(target, timestamp);
}
void SyntheticPinchGesture::ForwardTouchEvent(
SyntheticGestureTarget* target, const base::TimeTicks& timestamp) {
touch_event_.timeStampSeconds = ConvertTimestampToSeconds(timestamp);
target->DispatchInputEventToPlatform(touch_event_);
}
void SyntheticPinchGesture::SetupCoordinatesAndStopTime(
SyntheticGestureTarget* target) {
// To achieve the specified scaling factor, the ratio of the final to the
// initial span (distance between the pointers) has to be equal to the scaling
// factor. Since we're moving both pointers at the same speed, each pointer's
// distance to the anchor is half the span.
float initial_distance_to_anchor, final_distance_to_anchor;
if (params_.scale_factor > 1.0f) { // zooming in
initial_distance_to_anchor = target->GetMinScalingSpanInDips() / 2.0f;
final_distance_to_anchor =
(initial_distance_to_anchor + target->GetTouchSlopInDips()) *
params_.scale_factor;
} else { // zooming out
final_distance_to_anchor = target->GetMinScalingSpanInDips() / 2.0f;
initial_distance_to_anchor =
(final_distance_to_anchor / params_.scale_factor) +
target->GetTouchSlopInDips();
}
start_y_0_ = params_.anchor.y() - initial_distance_to_anchor;
start_y_1_ = params_.anchor.y() + initial_distance_to_anchor;
max_pointer_delta_0_ = initial_distance_to_anchor - final_distance_to_anchor;
int64 total_duration_in_us = static_cast<int64>(
1e6 * (static_cast<double>(std::abs(2 * max_pointer_delta_0_)) /
params_.relative_pointer_speed_in_pixels_s));
DCHECK_GT(total_duration_in_us, 0);
stop_time_ =
start_time_ + base::TimeDelta::FromMicroseconds(total_duration_in_us);
}
float SyntheticPinchGesture::GetDeltaForPointer0AtTime(
const base::TimeTicks& timestamp) const {
// Make sure the final delta is correct. Using the computation below can lead
// to issues with floating point precision.
if (HasReachedTarget(timestamp))
return max_pointer_delta_0_;
float total_abs_delta = params_.relative_pointer_speed_in_pixels_s *
(timestamp - start_time_).InSecondsF();
float abs_delta_pointer_0 = total_abs_delta / 2.0f;
return (params_.scale_factor > 1.0f) ? -abs_delta_pointer_0
: abs_delta_pointer_0;
}
base::TimeTicks SyntheticPinchGesture::ClampTimestamp(
const base::TimeTicks& timestamp) const {
return std::min(timestamp, stop_time_);
}
bool SyntheticPinchGesture::HasReachedTarget(const base::TimeTicks& timestamp)
const {
return timestamp >= stop_time_;
}
} // namespace content
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