2 * Copyright (c) 2019 Samsung Electronics Co., Ltd.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include <dali/internal/event/events/pinch-gesture/pinch-gesture-recognizer.h>
24 #include <dali/public-api/events/touch-point.h>
25 #include <dali/public-api/math/vector2.h>
27 #include <dali/internal/event/events/pinch-gesture/pinch-gesture-event.h>
28 #include <dali/integration-api/events/touch-event-integ.h>
29 #include <dali/internal/event/common/scene-impl.h>
42 const float MINIMUM_DISTANCE_IN_MILLIINCH = 45.0f; // This value is used for measuring minimum pinch distance in pixel.
43 const float MINIMUM_DISTANCE_IN_PIXEL = 10.0f; // This value is for devices that do not provide a valid dpi value. (assumes 220dpi)
45 inline float GetDistance(const Integration::Point& point1, const Integration::Point& point2)
47 Vector2 vector(point1.GetScreenPosition() - point2.GetScreenPosition());
48 return vector.Length();
51 inline Vector2 GetCenterPoint(const Integration::Point& point1, const Integration::Point& point2)
53 return Vector2(point1.GetScreenPosition() + point2.GetScreenPosition()) * 0.5f;
56 inline bool IsValidDpi( const Vector2& dpi )
58 return dpi.x > 0.f && dpi.y > 0.f;
61 inline float GetDefaultMinimumPinchDistance( const Vector2& dpi )
63 return IsValidDpi( dpi ) ? ( ( MINIMUM_DISTANCE_IN_MILLIINCH * std::min( dpi.x, dpi.y ) ) / 1000.f ) : MINIMUM_DISTANCE_IN_PIXEL;
66 } // unnamed namespace
68 PinchGestureRecognizer::PinchGestureRecognizer( Observer& observer, Vector2 screenSize, Vector2 screenDpi, float minimumPinchDistance, uint32_t minimumTouchEvents, uint32_t minimumTouchEventsAfterStart )
69 : GestureRecognizer( screenSize, Gesture::Pinch ),
70 mObserver( observer ),
73 mDefaultMinimumDistanceDelta( GetDefaultMinimumPinchDistance( screenDpi ) ),
74 mStartingDistance( 0.0f ),
75 mMinimumTouchEvents( minimumTouchEvents ),
76 mMinimumTouchEventsAfterStart( minimumTouchEventsAfterStart )
78 SetMinimumPinchDistance( minimumPinchDistance );
81 PinchGestureRecognizer::~PinchGestureRecognizer()
85 void PinchGestureRecognizer::SetMinimumPinchDistance(float value)
87 mMinimumDistanceDelta = value >= 0.0f ? value : mDefaultMinimumDistanceDelta;
90 void PinchGestureRecognizer::SendEvent(const Integration::TouchEvent& event)
92 int pointCount = event.GetPointCount();
93 GestureRecognizerPtr ptr(this); // To keep us from being destroyed during the life-time of this method
101 // Change state to possible as we have two touch points.
103 mTouchEvents.push_back(event);
112 // We no longer have two touch points so change state back to Clear.
114 mTouchEvents.clear();
118 const Integration::Point& currentPoint1 = event.points[0];
119 const Integration::Point& currentPoint2 = event.points[1];
121 if (currentPoint1.GetState() == PointState::UP || currentPoint2.GetState() == PointState::UP)
123 // One of our touch points has an Up event so change our state back to Clear.
125 mTouchEvents.clear();
129 mTouchEvents.push_back(event);
131 // We can only determine a pinch after a certain number of touch points have been collected.
132 if( mTouchEvents.size() >= mMinimumTouchEvents )
134 const Integration::Point& firstPoint1 = mTouchEvents[0].points[0];
135 const Integration::Point& firstPoint2 = mTouchEvents[0].points[1];
137 float firstDistance = GetDistance(firstPoint1, firstPoint2);
138 float currentDistance = GetDistance(currentPoint1, currentPoint2);
139 float distanceChanged = firstDistance - currentDistance;
141 // Check if distance has changed enough
142 if (fabsf(distanceChanged) > mMinimumDistanceDelta)
144 // Remove the first few events from the vector otherwise values are exaggerated
145 mTouchEvents.erase( mTouchEvents.begin(), mTouchEvents.end() - mMinimumTouchEvents );
147 if ( !mTouchEvents.empty() )
149 mStartingDistance = GetDistance(mTouchEvents.begin()->points[0], mTouchEvents.begin()->points[1]);
151 // Send pinch started
152 SendPinch(Gesture::Started, event);
157 mTouchEvents.clear();
160 if (mState == Possible)
162 // No pinch, so restart detection
164 mTouchEvents.clear();
176 // Send pinch finished event
177 SendPinch(Gesture::Finished, event);
180 mTouchEvents.clear();
184 const Integration::Point& currentPoint1 = event.points[0];
185 const Integration::Point& currentPoint2 = event.points[1];
187 if (currentPoint1.GetState() == PointState::UP || currentPoint2.GetState() == PointState::UP)
189 mTouchEvents.push_back(event);
190 // Send pinch finished event
191 SendPinch(Gesture::Finished, event);
194 mTouchEvents.clear();
198 mTouchEvents.push_back(event);
200 if( mTouchEvents.size() >= mMinimumTouchEventsAfterStart )
202 // Send pinch continuing
203 SendPinch(Gesture::Continuing, event);
205 mTouchEvents.clear();
214 void PinchGestureRecognizer::Update(const GestureRequest& request)
219 void PinchGestureRecognizer::SendPinch(Gesture::State state, const Integration::TouchEvent& currentEvent)
221 PinchGestureEvent gesture(state);
223 if ( !mTouchEvents.empty() )
225 const Integration::TouchEvent& firstEvent = mTouchEvents[0];
227 // Assert if we have been holding TouchEvents that do not have 2 points
228 DALI_ASSERT_DEBUG( firstEvent.GetPointCount() == 2 );
230 // We should use the current event in our calculations unless it does not have two points.
231 // If it does not have two points, then we should use the last point in mTouchEvents.
232 Integration::TouchEvent event( currentEvent );
233 if ( event.GetPointCount() != 2 )
235 event = *mTouchEvents.rbegin();
238 const Integration::Point& firstPoint1( firstEvent.points[0] );
239 const Integration::Point& firstPoint2( firstEvent.points[1] );
240 const Integration::Point& currentPoint1( event.points[0] );
241 const Integration::Point& currentPoint2( event.points[1] );
243 float firstDistance = GetDistance(firstPoint1, firstPoint2);
244 float currentDistance = GetDistance(currentPoint1, currentPoint2);
245 gesture.scale = currentDistance / mStartingDistance;
247 float distanceDelta = fabsf(firstDistance - currentDistance);
248 float timeDelta = static_cast<float> ( currentEvent.time - firstEvent.time );
249 gesture.speed = ( distanceDelta / timeDelta ) * 1000.0f;
251 gesture.centerPoint = GetCenterPoint(currentPoint1, currentPoint2);
255 // Something has gone wrong, just cancel the gesture.
256 gesture.state = Gesture::Cancelled;
259 gesture.time = currentEvent.time;
263 // Create another handle so the recognizer cannot be destroyed during process function
264 GestureRecognizerPtr recognizerHandle = this;
266 mObserver.Process(*mScene, gesture);
270 void PinchGestureRecognizer::SetMinimumTouchEvents( uint32_t value )
272 mMinimumTouchEvents = value;
275 void PinchGestureRecognizer::SetMinimumTouchEventsAfterStart( uint32_t value )
277 mMinimumTouchEventsAfterStart = value;
280 } // namespace Internal