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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 "content/common/input/input_event.h"
#include "ui/events/latency_info.h"
namespace content {
SyntheticPinchGesture::SyntheticPinchGesture(
const SyntheticPinchGestureParams& params)
: params_(params),
current_y_0_(0.0f),
current_y_1_(0.0f),
target_y_0_(0.0f),
target_y_1_(0.0f),
gesture_source_type_(SyntheticGestureParams::DEFAULT_INPUT),
state_(SETUP) {
DCHECK_GE(params_.total_num_pixels_covered, 0);
}
SyntheticPinchGesture::~SyntheticPinchGesture() {}
SyntheticGesture::Result SyntheticPinchGesture::ForwardInputEvents(
const base::TimeDelta& interval, SyntheticGestureTarget* target) {
if (state_ == SETUP) {
gesture_source_type_ = params_.gesture_source_type;
if (gesture_source_type_ == SyntheticGestureParams::DEFAULT_INPUT)
gesture_source_type_ = target->GetDefaultSyntheticGestureSourceType();
if (!target->SupportsSyntheticGestureSourceType(gesture_source_type_))
return SyntheticGesture::GESTURE_SOURCE_TYPE_NOT_SUPPORTED_BY_PLATFORM;
state_ = STARTED;
}
DCHECK_NE(gesture_source_type_, SyntheticGestureParams::DEFAULT_INPUT);
if (gesture_source_type_ == SyntheticGestureParams::TOUCH_INPUT)
ForwardTouchInputEvents(interval, target);
else
return SyntheticGesture::GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED;
return (state_ == DONE) ? SyntheticGesture::GESTURE_FINISHED
: SyntheticGesture::GESTURE_RUNNING;
}
void SyntheticPinchGesture::ForwardTouchInputEvents(
const base::TimeDelta& interval, SyntheticGestureTarget* target) {
switch (state_) {
case STARTED:
// Check for an early finish.
if (params_.total_num_pixels_covered == 0) {
state_ = DONE;
break;
}
SetupCoordinates(target);
PressTouchPoints(target);
state_ = MOVING;
break;
case MOVING:
UpdateTouchPoints(interval);
MoveTouchPoints(target);
if (HasReachedTarget()) {
ReleaseTouchPoints(target);
state_ = DONE;
}
break;
case SETUP:
NOTREACHED() << "State SETUP invalid for synthetic pinch.";
case DONE:
NOTREACHED() << "State DONE invalid for synthetic pinch.";
}
}
void SyntheticPinchGesture::UpdateTouchPoints(base::TimeDelta interval) {
// Compute the delta for the first pointer. The other one moves exactly
// the same but in the opposite direction.
float delta = GetDeltaForPointer0(interval);
current_y_0_ += delta;
current_y_1_ -= delta;
}
void SyntheticPinchGesture::PressTouchPoints(SyntheticGestureTarget* target) {
touch_event_.PressPoint(params_.anchor.x(), current_y_0_);
touch_event_.PressPoint(params_.anchor.x(), current_y_1_);
ForwardTouchEvent(target);
}
void SyntheticPinchGesture::MoveTouchPoints(SyntheticGestureTarget* target) {
// The current pointer positions are stored as float but the pointer
// coordinates of the input event are integers. Floor both positions so that
// in case of an odd distance one of the pointers (the one whose position goes
// down) moves one pixel further than the other. The explicit flooring is only
// needed for negative values.
touch_event_.MovePoint(0, params_.anchor.x(), floor(current_y_0_));
touch_event_.MovePoint(1, params_.anchor.x(), floor(current_y_1_));
ForwardTouchEvent(target);
}
void SyntheticPinchGesture::ReleaseTouchPoints(SyntheticGestureTarget* target) {
touch_event_.ReleasePoint(0);
touch_event_.ReleasePoint(1);
ForwardTouchEvent(target);
}
void SyntheticPinchGesture::ForwardTouchEvent(SyntheticGestureTarget* target)
const {
target->DispatchInputEventToPlatform(
InputEvent(touch_event_, ui::LatencyInfo(), false));
}
void SyntheticPinchGesture::SetupCoordinates(SyntheticGestureTarget* target) {
const float kTouchSlopInDips = target->GetTouchSlopInDips();
float inner_distance_to_anchor = 2 * kTouchSlopInDips;
float outer_distance_to_anchor = inner_distance_to_anchor +
params_.total_num_pixels_covered / 2.0f +
kTouchSlopInDips;
// Move pointers away from each other to zoom in
// or towards each other to zoom out.
if (params_.zoom_in) {
current_y_0_ = params_.anchor.y() - inner_distance_to_anchor;
current_y_1_ = params_.anchor.y() + inner_distance_to_anchor;
target_y_0_ = params_.anchor.y() - outer_distance_to_anchor;
target_y_1_ = params_.anchor.y() + outer_distance_to_anchor;
} else {
current_y_0_ = params_.anchor.y() - outer_distance_to_anchor;
current_y_1_ = params_.anchor.y() + outer_distance_to_anchor;
target_y_0_ = params_.anchor.y() - inner_distance_to_anchor;
target_y_1_ = params_.anchor.y() + inner_distance_to_anchor;
}
}
float SyntheticPinchGesture::GetDeltaForPointer0(
const base::TimeDelta& interval) const {
float total_abs_delta =
params_.relative_pointer_speed_in_pixels_s * interval.InSecondsF();
// Make sure we're not moving too far in the final step.
total_abs_delta =
std::min(total_abs_delta, ComputeAbsoluteRemainingDistance());
float abs_delta_pointer_0 = total_abs_delta / 2;
return params_.zoom_in ? -abs_delta_pointer_0 : abs_delta_pointer_0;
}
float SyntheticPinchGesture::ComputeAbsoluteRemainingDistance() const {
float distance_0 = params_.zoom_in ? (current_y_0_ - target_y_0_)
: (target_y_0_ - current_y_0_);
DCHECK_GE(distance_0, 0);
// Both pointers move the same overall distance at the same speed.
return 2 * distance_0;
}
bool SyntheticPinchGesture::HasReachedTarget() const {
return ComputeAbsoluteRemainingDistance() == 0;
}
} // namespace content
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