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 "content/browser/renderer_host/input/synthetic_smooth_scroll_gesture.h" 6 7#include "base/logging.h" 8#include "ui/gfx/point_f.h" 9 10namespace content { 11namespace { 12 13gfx::Vector2d FloorTowardZero(const gfx::Vector2dF& vector) { 14 int x = vector.x() > 0 ? floor(vector.x()) : ceil(vector.x()); 15 int y = vector.y() > 0 ? floor(vector.y()) : ceil(vector.y()); 16 return gfx::Vector2d(x, y); 17} 18 19gfx::Vector2d CeilFromZero(const gfx::Vector2dF& vector) { 20 int x = vector.x() > 0 ? ceil(vector.x()) : floor(vector.x()); 21 int y = vector.y() > 0 ? ceil(vector.y()) : floor(vector.y()); 22 return gfx::Vector2d(x, y); 23} 24 25gfx::Vector2dF ProjectScalarOntoVector( 26 float scalar, const gfx::Vector2d& vector) { 27 return gfx::ScaleVector2d(vector, scalar / vector.Length()); 28} 29 30} // namespace 31 32SyntheticSmoothScrollGesture::SyntheticSmoothScrollGesture( 33 const SyntheticSmoothScrollGestureParams& params) 34 : params_(params), 35 gesture_source_type_(SyntheticGestureParams::DEFAULT_INPUT), 36 state_(SETUP) {} 37 38SyntheticSmoothScrollGesture::~SyntheticSmoothScrollGesture() {} 39 40SyntheticGesture::Result SyntheticSmoothScrollGesture::ForwardInputEvents( 41 const base::TimeTicks& timestamp, SyntheticGestureTarget* target) { 42 if (state_ == SETUP) { 43 gesture_source_type_ = params_.gesture_source_type; 44 if (gesture_source_type_ == SyntheticGestureParams::DEFAULT_INPUT) 45 gesture_source_type_ = target->GetDefaultSyntheticGestureSourceType(); 46 47 state_ = STARTED; 48 current_scroll_segment_ = -1; 49 current_scroll_segment_stop_time_ = timestamp; 50 } 51 52 DCHECK_NE(gesture_source_type_, SyntheticGestureParams::DEFAULT_INPUT); 53 if (gesture_source_type_ == SyntheticGestureParams::TOUCH_INPUT) 54 ForwardTouchInputEvents(timestamp, target); 55 else if (gesture_source_type_ == SyntheticGestureParams::MOUSE_INPUT) 56 ForwardMouseInputEvents(timestamp, target); 57 else 58 return SyntheticGesture::GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED; 59 60 return (state_ == DONE) ? SyntheticGesture::GESTURE_FINISHED 61 : SyntheticGesture::GESTURE_RUNNING; 62} 63 64void SyntheticSmoothScrollGesture::ForwardTouchInputEvents( 65 const base::TimeTicks& timestamp, SyntheticGestureTarget* target) { 66 base::TimeTicks event_timestamp = timestamp; 67 switch (state_) { 68 case STARTED: 69 if (ScrollIsNoOp()) { 70 state_ = DONE; 71 break; 72 } 73 AddTouchSlopToFirstDistance(target); 74 ComputeNextScrollSegment(); 75 current_scroll_segment_start_position_ = params_.anchor; 76 PressTouchPoint(target, event_timestamp); 77 state_ = MOVING; 78 break; 79 case MOVING: { 80 event_timestamp = ClampTimestamp(timestamp); 81 gfx::Vector2dF delta = GetPositionDeltaAtTime(event_timestamp); 82 MoveTouchPoint(target, delta, event_timestamp); 83 84 if (FinishedCurrentScrollSegment(event_timestamp)) { 85 if (!IsLastScrollSegment()) { 86 current_scroll_segment_start_position_ += 87 params_.distances[current_scroll_segment_]; 88 ComputeNextScrollSegment(); 89 } else if (params_.prevent_fling) { 90 state_ = STOPPING; 91 } else { 92 ReleaseTouchPoint(target, event_timestamp); 93 state_ = DONE; 94 } 95 } 96 } break; 97 case STOPPING: 98 if (timestamp - current_scroll_segment_stop_time_ >= 99 target->PointerAssumedStoppedTime()) { 100 event_timestamp = current_scroll_segment_stop_time_ + 101 target->PointerAssumedStoppedTime(); 102 // Send one last move event, but don't change the location. Without this 103 // we'd still sometimes cause a fling on Android. 104 105 // Required to suppress flings on Aura, see 106 // |UpdateWebTouchPointFromUIEvent|, remove when crbug.com/332418 107 // is fixed. 108 touch_event_.touches[0].position.y += 0.001f; 109 110 ForwardTouchEvent(target, event_timestamp); 111 ReleaseTouchPoint(target, event_timestamp); 112 state_ = DONE; 113 } 114 break; 115 case SETUP: 116 NOTREACHED() 117 << "State STARTED invalid for synthetic scroll using touch input."; 118 case DONE: 119 NOTREACHED() 120 << "State DONE invalid for synthetic scroll using touch input."; 121 } 122} 123 124void SyntheticSmoothScrollGesture::ForwardMouseInputEvents( 125 const base::TimeTicks& timestamp, SyntheticGestureTarget* target) { 126 switch (state_) { 127 case STARTED: 128 if (ScrollIsNoOp()) { 129 state_ = DONE; 130 break; 131 } 132 ComputeNextScrollSegment(); 133 state_ = MOVING; 134 // Fall through to forward the first event. 135 case MOVING: { 136 // Even though WebMouseWheelEvents take floating point deltas, 137 // internally the scroll position is stored as an integer. We therefore 138 // keep track of the discrete delta which is consistent with the 139 // internal scrolling state. This ensures that when the gesture has 140 // finished we've scrolled exactly the specified distance. 141 base::TimeTicks event_timestamp = ClampTimestamp(timestamp); 142 gfx::Vector2dF current_scroll_segment_total_delta = 143 GetPositionDeltaAtTime(event_timestamp); 144 gfx::Vector2d delta_discrete = 145 FloorTowardZero(current_scroll_segment_total_delta - 146 current_scroll_segment_total_delta_discrete_); 147 ForwardMouseWheelEvent(target, delta_discrete, event_timestamp); 148 current_scroll_segment_total_delta_discrete_ += delta_discrete; 149 150 if (FinishedCurrentScrollSegment(event_timestamp)) { 151 if (!IsLastScrollSegment()) { 152 current_scroll_segment_total_delta_discrete_ = gfx::Vector2d(); 153 ComputeNextScrollSegment(); 154 ForwardMouseInputEvents(timestamp, target); 155 } else { 156 state_ = DONE; 157 } 158 } 159 } break; 160 case SETUP: 161 NOTREACHED() 162 << "State STARTED invalid for synthetic scroll using touch input."; 163 case STOPPING: 164 NOTREACHED() 165 << "State STOPPING invalid for synthetic scroll using touch input."; 166 case DONE: 167 NOTREACHED() 168 << "State DONE invalid for synthetic scroll using touch input."; 169 } 170} 171 172void SyntheticSmoothScrollGesture::ForwardTouchEvent( 173 SyntheticGestureTarget* target, const base::TimeTicks& timestamp) { 174 touch_event_.timeStampSeconds = ConvertTimestampToSeconds(timestamp); 175 176 target->DispatchInputEventToPlatform(touch_event_); 177} 178 179void SyntheticSmoothScrollGesture::ForwardMouseWheelEvent( 180 SyntheticGestureTarget* target, 181 const gfx::Vector2dF& delta, 182 const base::TimeTicks& timestamp) const { 183 blink::WebMouseWheelEvent mouse_wheel_event = 184 SyntheticWebMouseWheelEventBuilder::Build(delta.x(), delta.y(), 0, false); 185 186 mouse_wheel_event.x = params_.anchor.x(); 187 mouse_wheel_event.y = params_.anchor.y(); 188 189 mouse_wheel_event.timeStampSeconds = ConvertTimestampToSeconds(timestamp); 190 191 target->DispatchInputEventToPlatform(mouse_wheel_event); 192} 193 194void SyntheticSmoothScrollGesture::PressTouchPoint( 195 SyntheticGestureTarget* target, const base::TimeTicks& timestamp) { 196 DCHECK_EQ(current_scroll_segment_, 0); 197 touch_event_.PressPoint(params_.anchor.x(), params_.anchor.y()); 198 ForwardTouchEvent(target, timestamp); 199} 200 201void SyntheticSmoothScrollGesture::MoveTouchPoint( 202 SyntheticGestureTarget* target, 203 const gfx::Vector2dF& delta, 204 const base::TimeTicks& timestamp) { 205 DCHECK_GE(current_scroll_segment_, 0); 206 DCHECK_LT(current_scroll_segment_, 207 static_cast<int>(params_.distances.size())); 208 gfx::PointF touch_position = current_scroll_segment_start_position_ + delta; 209 touch_event_.MovePoint(0, touch_position.x(), touch_position.y()); 210 ForwardTouchEvent(target, timestamp); 211} 212 213void SyntheticSmoothScrollGesture::ReleaseTouchPoint( 214 SyntheticGestureTarget* target, const base::TimeTicks& timestamp) { 215 DCHECK_EQ(current_scroll_segment_, 216 static_cast<int>(params_.distances.size()) - 1); 217 touch_event_.ReleasePoint(0); 218 ForwardTouchEvent(target, timestamp); 219} 220 221void SyntheticSmoothScrollGesture::AddTouchSlopToFirstDistance( 222 SyntheticGestureTarget* target) { 223 DCHECK_GE(params_.distances.size(), 1ul); 224 gfx::Vector2d& first_scroll_distance = params_.distances[0]; 225 DCHECK_GT(first_scroll_distance.Length(), 0); 226 first_scroll_distance += CeilFromZero(ProjectScalarOntoVector( 227 target->GetTouchSlopInDips(), first_scroll_distance)); 228} 229 230gfx::Vector2dF SyntheticSmoothScrollGesture::GetPositionDeltaAtTime( 231 const base::TimeTicks& timestamp) const { 232 // Make sure the final delta is correct. Using the computation below can lead 233 // to issues with floating point precision. 234 if (FinishedCurrentScrollSegment(timestamp)) 235 return params_.distances[current_scroll_segment_]; 236 237 float delta_length = 238 params_.speed_in_pixels_s * 239 (timestamp - current_scroll_segment_start_time_).InSecondsF(); 240 return ProjectScalarOntoVector(delta_length, 241 params_.distances[current_scroll_segment_]); 242} 243 244void SyntheticSmoothScrollGesture::ComputeNextScrollSegment() { 245 current_scroll_segment_++; 246 DCHECK_LT(current_scroll_segment_, 247 static_cast<int>(params_.distances.size())); 248 int64 total_duration_in_us = static_cast<int64>( 249 1e6 * (params_.distances[current_scroll_segment_].Length() / 250 params_.speed_in_pixels_s)); 251 DCHECK_GT(total_duration_in_us, 0); 252 current_scroll_segment_start_time_ = current_scroll_segment_stop_time_; 253 current_scroll_segment_stop_time_ = 254 current_scroll_segment_start_time_ + 255 base::TimeDelta::FromMicroseconds(total_duration_in_us); 256} 257 258base::TimeTicks SyntheticSmoothScrollGesture::ClampTimestamp( 259 const base::TimeTicks& timestamp) const { 260 return std::min(timestamp, current_scroll_segment_stop_time_); 261} 262 263bool SyntheticSmoothScrollGesture::FinishedCurrentScrollSegment( 264 const base::TimeTicks& timestamp) const { 265 return timestamp >= current_scroll_segment_stop_time_; 266} 267 268bool SyntheticSmoothScrollGesture::IsLastScrollSegment() const { 269 DCHECK_LT(current_scroll_segment_, 270 static_cast<int>(params_.distances.size())); 271 return current_scroll_segment_ == 272 static_cast<int>(params_.distances.size()) - 1; 273} 274 275bool SyntheticSmoothScrollGesture::ScrollIsNoOp() const { 276 return params_.distances.size() == 0 || params_.distances[0].IsZero(); 277} 278 279} // namespace content 280