dali/internal/event/events/tap-gesture/tap-gesture-recognizer.cpp

   1 /*
   2  * Copyright (c) 2022 Samsung Electronics Co., Ltd.
   3  *
   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
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  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.
  15  *
  16  */
  17
  18 // CLASS HEADER
  19 #include <dali/internal/event/events/tap-gesture/tap-gesture-recognizer.h>
  20
  21 // EXTERNAL INCLUDES
  22 #include <cmath>
  23
  24 #include <dali/public-api/math/vector2.h>
  25
  26 #include <dali/integration-api/events/touch-event-integ.h>
  27
  28 // INTERNAL INCLUDES
  29 #include <dali/internal/event/common/scene-impl.h>
  30 #include <dali/internal/event/events/gesture-requests.h>
  31
  32 namespace Dali
  33 {
  34 namespace Internal
  35 {
  36 namespace
  37 {
  38 // TODO: Set these according to DPI
  39 constexpr float MAXIMUM_MOTION_ALLOWED = 20.0f;
  40 } // unnamed namespace
  41
  42 TapGestureRecognizer::TapGestureRecognizer(Observer& observer, Vector2 screenSize, const TapGestureRequest& request, uint32_t maximumAllowedTime)
  43 : GestureRecognizer(screenSize, GestureType::TAP),
  44   mObserver(observer),
  45   mState(CLEAR),
  46   mMinimumTapsRequired(request.minTaps),
  47   mMaximumTapsRequired(request.maxTaps),
  48   mTapsRegistered(0),
  49   mTouchPosition(),
  50   mTouchTime(0u),
  51   mLastTapTime(0u),
  52   mLastTouchTime(0u),
  53   mMaximumAllowedTime(maximumAllowedTime)
  54 {
  55 }
  56
  57 TapGestureRecognizer::~TapGestureRecognizer() = default;
  58
  59 void TapGestureRecognizer::SendEvent(const Integration::TouchEvent& event)
  60 {
  61   GestureRecognizerPtr ptr(this); // To keep us from being destroyed during the life-time of this method
  62
  63   if(event.GetPointCount() == 1)
  64   {
  65     const Integration::Point& point      = event.points[0];
  66     PointState::Type          pointState = point.GetState();
  67
  68     switch(mState)
  69     {
  70       case CLEAR:
  71       {
  72         if(pointState == PointState::DOWN)
  73         {
  74           SetupForTouchDown(event, point);
  75           mLastTouchTime = event.time;
  76         }
  77         break;
  78       }
  79
  80       case TOUCHED:
  81       {
  82         uint32_t deltaBetweenTouchDownTouchUp = event.time - mTouchTime;
  83
  84         if(pointState == PointState::UP)
  85         {
  86           if(deltaBetweenTouchDownTouchUp < mMaximumAllowedTime)
  87           {
  88             mLastTapTime = event.time;
  89             EmitSingleTap(event.time, point);
  90             mState = REGISTERED;
  91           }
  92           else
  93           {
  94             mState = CLEAR;
  95           }
  96         }
  97         else if(pointState == PointState::INTERRUPTED)
  98         {
  99           mState = CLEAR;
 100         }
 101         break;
 102       }
 103
 104       case REGISTERED:
 105       {
 106         if(pointState == PointState::UP)
 107         {
 108           uint32_t deltaBetweenLastTouchDownTouchUp = event.time - mLastTouchTime;
 109           // Clear if the time between touch down and touch up is long.
 110           if(deltaBetweenLastTouchDownTouchUp > mMaximumAllowedTime)
 111           {
 112             mState = CLEAR;
 113           }
 114           else
 115           {
 116             mLastTapTime = event.time;
 117             EmitGesture(GestureState::STARTED, event.time);
 118           }
 119         }
 120         else if(pointState == PointState::DOWN)
 121         {
 122           const Vector2& screen(point.GetScreenPosition());
 123           Vector2        distanceDelta(std::abs(mTouchPosition.x - screen.x),
 124                                 std::abs(mTouchPosition.y - screen.y));
 125
 126           uint32_t deltaBetweenInitTouchDownCurrentTouchDown = event.time - mTouchTime;
 127           uint32_t timeDelta                                 = event.time - mLastTapTime;
 128           mLastTouchTime                                     = event.time;
 129           ++mTapsRegistered;
 130
 131           if(distanceDelta.x > MAXIMUM_MOTION_ALLOWED ||
 132              distanceDelta.y > MAXIMUM_MOTION_ALLOWED ||
 133              timeDelta > mMaximumAllowedTime ||                                 // If the time between tabs is long, it starts over from SetupForTouchDown.
 134              deltaBetweenInitTouchDownCurrentTouchDown > mMaximumAllowedTime || // If it times out compared to the first touchdown time, it starts over from SetupForTouchDown.
 135              mTapsRegistered > mMaximumTapsRequired)                            // If it is greater than MaximumTapsRequired, it starts over from SetupForTouchDown.
 136           {
 137             SetupForTouchDown(event, point);
 138           }
 139           else
 140           {
 141             EmitPossibleState(event);
 142           }
 143         }
 144         break;
 145       }
 146
 147       case FAILED:
 148       default:
 149       {
 150         mState = CLEAR;
 151         break;
 152       }
 153     }
 154   }
 155   else
 156   {
 157     mState = FAILED;
 158
 159     // We have entered a multi-touch event so emit registered gestures if required.
 160     EmitGesture(GestureState::STARTED, event.time);
 161   }
 162 }
 163
 164 void TapGestureRecognizer::SetupForTouchDown(const Integration::TouchEvent& event, const Integration::Point& point)
 165 {
 166   mTouchPosition  = point.GetScreenPosition();
 167   mTouchTime      = event.time;
 168   mLastTapTime    = 0u;
 169   mTapsRegistered = 0;
 170   mState          = TOUCHED;
 171
 172   EmitPossibleState(event);
 173 }
 174
 175 void TapGestureRecognizer::EmitPossibleState(const Integration::TouchEvent& event)
 176 {
 177   TapGestureEvent tapEvent(GestureState::POSSIBLE);
 178   tapEvent.point = mTouchPosition;
 179   tapEvent.time  = event.time;
 180
 181   ProcessEvent(tapEvent);
 182 }
 183
 184 void TapGestureRecognizer::Update(const GestureRequest& request)
 185 {
 186   const TapGestureRequest& tap = static_cast<const TapGestureRequest&>(request);
 187
 188   mMinimumTapsRequired = tap.minTaps;
 189   mMaximumTapsRequired = tap.maxTaps;
 190 }
 191
 192 void TapGestureRecognizer::SetMaximumAllowedTime(uint32_t time)
 193 {
 194   mMaximumAllowedTime = time;
 195 }
 196
 197 void TapGestureRecognizer::EmitGesture(GestureState state, uint32_t time)
 198 {
 199   if((state == GestureState::CANCELLED) ||
 200      (mTapsRegistered >= mMinimumTapsRequired && mTapsRegistered <= mMaximumTapsRequired))
 201
 202   {
 203     TapGestureEvent event(state);
 204     EmitTap(time, event);
 205   }
 206 }
 207
 208 void TapGestureRecognizer::EmitSingleTap(uint32_t time, const Integration::Point& point)
 209 {
 210   TapGestureEvent event(GestureState::STARTED);
 211   const Vector2&  screen(point.GetScreenPosition());
 212   Vector2         distanceDelta(std::abs(mTouchPosition.x - screen.x),
 213                         std::abs(mTouchPosition.y - screen.y));
 214
 215   if(distanceDelta.x > MAXIMUM_MOTION_ALLOWED ||
 216      distanceDelta.y > MAXIMUM_MOTION_ALLOWED)
 217   {
 218     event.state = GestureState::CANCELLED;
 219   }
 220   mTapsRegistered = 1u;
 221   EmitTap(time, event);
 222 }
 223
 224 void TapGestureRecognizer::EmitTap(uint32_t time, TapGestureEvent& event)
 225 {
 226   event.numberOfTaps = mTapsRegistered;
 227   event.point        = mTouchPosition;
 228   event.time         = time;
 229
 230   ProcessEvent(event);
 231 }
 232
 233 void TapGestureRecognizer::ProcessEvent(TapGestureEvent& event)
 234 {
 235   event.sourceType = mSourceType;
 236   event.sourceData = mSourceData;
 237   if(mScene)
 238   {
 239     // Create another handle so the recognizer cannot be destroyed during process function
 240     GestureRecognizerPtr recognizerHandle = this;
 241     mObserver.Process(*mScene, event);
 242   }
 243 }
 244
 245 } // namespace Internal
 246
 247 } // namespace Dali