1 #ifndef __DALI_PAN_GESTURE_DETECTOR_H__
2 #define __DALI_PAN_GESTURE_DETECTOR_H__
5 * Copyright (c) 2018 Samsung Electronics Co., Ltd.
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
22 #include <cstdint> // uint32_t
25 #include <dali/public-api/events/gesture-detector.h>
26 #include <dali/public-api/object/property-index-ranges.h>
27 #include <dali/public-api/signals/dali-signal.h>
34 namespace Internal DALI_INTERNAL
36 class PanGestureDetector;
42 * @addtogroup dali_core_events
47 * @brief This class looks for panning (or dragging) gestures.
49 * The user will be pressing one or more fingers on an actor while they pan it.
51 * The application programmer can use this gesture detector as follows:
53 * PanGestureDetector detector = PanGestureDetector::New();
54 * detector.Attach(myActor);
55 * detector.DetectedSignal().Connect(this, &MyApplication::OnPan);
57 * // Detect pan gesture for single and double touch.
58 * detector.SetMaximumTouchesRequired(2);
65 * | %Signal Name | Method |
66 * |--------------|-----------------------|
67 * | panDetected | @ref DetectedSignal() |
69 class DALI_CORE_API PanGestureDetector : public GestureDetector
74 * @brief Enumeration for the instance of properties belonging to the PanGestureDetector class.
80 * @brief Enumeration for the instance of properties belonging to the PanGestureDetector class.
85 SCREEN_POSITION = DEFAULT_GESTURE_DETECTOR_PROPERTY_START_INDEX, ///< name "screenPosition", type Vector2 @SINCE_1_0.0
86 SCREEN_DISPLACEMENT, ///< name "screenDisplacement", type Vector2 @SINCE_1_0.0
87 SCREEN_VELOCITY, ///< name "screenVelocity", type Vector2 @SINCE_1_0.0
88 LOCAL_POSITION, ///< name "localPosition", type Vector2 @SINCE_1_0.0
89 LOCAL_DISPLACEMENT, ///< name "localDisplacement", type Vector2 @SINCE_1_0.0
90 LOCAL_VELOCITY, ///< name "localVelocity", type Vector2 @SINCE_1_0.0
91 PANNING, ///< name "panning", type bool @SINCE_1_0.0
96 typedef Signal< void ( Actor, const PanGesture& ) > DetectedSignalType; ///< Pan gesture detected signal type @SINCE_1_0.0
99 typedef std::pair< Radian, Radian > AngleThresholdPair; ///< Range of angles for a direction @SINCE_1_0.0
101 static const Radian DIRECTION_LEFT; ///< For a left pan (-PI Radians).
102 static const Radian DIRECTION_RIGHT; ///< For a right pan (0 Radians).
103 static const Radian DIRECTION_UP; ///< For an up pan (-0.5 * PI Radians).
104 static const Radian DIRECTION_DOWN; ///< For a down pan (0.5 * PI Radians).
105 static const Radian DIRECTION_HORIZONTAL; ///< For a left and right pan (PI Radians). Useful for AddDirection().
106 static const Radian DIRECTION_VERTICAL; ///< For an up and down pan (-0.5 * PI Radians). Useful for AddDirection().
108 static const Radian DEFAULT_THRESHOLD; ///< The default threshold is PI * 0.25 radians (or 45 degrees).
110 public: // Creation & Destruction
113 * @brief Creates an uninitialized PanGestureDetector; this can be initialized with PanGestureDetector::New().
115 * Calling member functions with an uninitialized PanGestureDetector handle is not allowed.
118 PanGestureDetector();
121 * @brief Creates an initialized PanGestureDetector.
124 * @return A handle to a newly allocated Dali resource
126 static PanGestureDetector New();
129 * @brief Downcasts a handle to PanGestureDetector handle.
131 * If handle points to a PanGestureDetector object, the
132 * downcast produces valid handle. If not, the returned handle is left uninitialized.
134 * @param[in] handle Handle to an object
135 * @return Handle to a PanGestureDetector object or an uninitialized handle
137 static PanGestureDetector DownCast( BaseHandle handle );
142 * This is non-virtual since derived Handle types must not contain data or virtual methods.
145 ~PanGestureDetector();
148 * @brief This copy constructor is required for (smart) pointer semantics.
151 * @param[in] handle A reference to the copied handle
153 PanGestureDetector(const PanGestureDetector& handle);
156 * @brief This assignment operator is required for (smart) pointer semantics.
159 * @param[in] rhs A reference to the copied handle
160 * @return A reference to this
162 PanGestureDetector& operator=(const PanGestureDetector& rhs);
167 * @brief This is the minimum number of touches required for the pan gesture to be detected.
170 * @param[in] minimum Minimum touches required
171 * @pre The gesture detector has been initialized.
172 * @note The default minimum is '1'.
174 void SetMinimumTouchesRequired(uint32_t minimum);
177 * @brief This is the maximum number of touches required for the pan gesture to be detected.
180 * @param[in] maximum Maximum touches required
181 * @pre The gesture detector has been initialized.
182 * @note The default maximum is '1'.
184 void SetMaximumTouchesRequired(uint32_t maximum);
189 * @brief Retrieves the minimum number of touches required for the pan gesture to be detected.
192 * @return The minimum touches required
193 * @pre The gesture detector has been initialized.
195 uint32_t GetMinimumTouchesRequired() const;
198 * @brief Retrieves the maximum number of touches required for the pan gesture to be detected.
201 * @return The maximum touches required
202 * @pre The gesture detector has been initialized.
204 uint32_t GetMaximumTouchesRequired() const;
206 public: // Directional Panning
209 * @brief The pan gesture is only emitted if the pan occurs in the direction specified by this method with a +/- threshold allowance.
211 * The angle is from -180 -> 0 -> 180 degrees (or -M_PI -> 0 -> M_PI in radians) i.e:
214 * -90.0f ( -0.5f * PI )
217 * 180.0f ( PI ) ------------- 0.0f ( 0.0f )
220 * 90.0f ( 0.5f * PI )
223 * If an angle of 0.0 degrees is specified and the threshold is 45 degrees then the acceptable
224 * direction range is from -45 to 45 degrees.
227 * @param[in] angle The angle that pan should be allowed
228 * @param[in] threshold The threshold around that angle
230 * @pre The gesture detector has been initialized.
231 * @note The angle added using this API is only checked when the gesture first starts, after that,
232 * this detector will emit the gesture regardless of what angle the pan is moving.
233 * @note The user can add as many angles as they require.
234 * @note If an angle outside the range above is given, then it is wrapped within the range, i.e.
235 * 190 degrees becomes -170 degrees and 370 degrees becomes 10 degrees.
236 * @note As long as you specify the type, you can also pass in a Dali::Degree to this method.
237 * @note If no threshold is provided, then the default threshold (PI * 0.25) is used.
238 * @note If the threshold is greater than PI, then PI will be used as the threshold.
241 void AddAngle( Radian angle, Radian threshold = DEFAULT_THRESHOLD );
244 * @brief A helper method for adding bi-directional angles where the pan should take place.
246 * In other words, if 0 is requested, then PI will also be added so that we have both left and
250 * @param[in] direction The direction of panning required
251 * @param[in] threshold The threshold
253 * @pre The gesture detector has been initialized.
255 * @note If a direction outside the range above is given, then it is wrapped within the range, i.e.
256 * 190 degrees becomes -170 degrees and 370 degrees becomes 10 degrees.
257 * @note If no threshold is provided, then the default threshold (PI * 0.25) is used.
258 * @note If the threshold is greater than PI, then PI will be used as the threshold.
259 * @note As long as you specify the type, you can also pass in a Dali::Degree to this method.
263 void AddDirection( Radian direction, Radian threshold = DEFAULT_THRESHOLD );
266 * @brief Returns the count of angles that this pan gesture detector emits a signal.
270 * @pre The gesture detector has been initialized.
272 size_t GetAngleCount() const;
275 * @brief Returns the angle by index that this pan gesture detector emits a signal.
278 * @param[in] index The angle's index
279 * @return An angle threshold pair, or a zero valued angle pair when index is invalid
280 * @pre The gesture detector has been initialized.
281 * @pre The index is less than GetAngleCount()
283 AngleThresholdPair GetAngle(size_t index) const;
286 * @brief Clears any directional angles that are used by the gesture detector.
288 * After this, the pan gesture
289 * will be emitted for a pan in ANY direction.
291 * @pre The gesture detector has been initialized.
296 * @brief Removes the angle specified from the container.
299 * @param[in] angle The angle to remove
300 * @pre The gesture detector has been initialized.
301 * @note This will only remove the first instance of the angle found from the container.
302 * @note If an angle outside the range in AddAngle() is given, then the value is wrapped within
303 * the range and that is removed.
305 void RemoveAngle( Radian angle );
308 * @brief Removes the two angles that make up the direction from the container.
311 * @param[in] direction The direction to remove
312 * @pre The gesture detector has been initialized.
313 * @note If a direction outside the range in AddAngle() is given, then the value is wrapped within
314 * the range and that is removed.
316 void RemoveDirection( Radian direction );
321 * @brief This signal is emitted when the pan gesture is detected on the attached actor.
323 * A callback of the following type may be connected:
325 * void YourCallbackName( Actor actor, const PanGesture& gesture );
328 * @return The signal to connect to
329 * @pre The gesture detector has been initialized.
331 DetectedSignalType& DetectedSignal();
333 public: // Pan Properties Setters
336 * @brief Allows setting of the pan properties that are returned in constraints.
339 * @param[in] pan The pan gesture to set
340 * @note If a normal pan is taking place, then any value set is ignored.
342 static void SetPanGestureProperties( const PanGesture& pan );
344 public: // Not intended for Application developers
348 * @brief This constructor is used by PanGestureDetector::New() methods.
351 * @param[in] internal A pointer to a newly allocated Dali resource
353 explicit DALI_INTERNAL PanGestureDetector(Internal::PanGestureDetector* internal);
364 #endif // __DALI_PAN_GESTURE_DETECTOR_H__