1 #ifndef DALI_PAN_GESTURE_DETECTOR_H
2 #define DALI_PAN_GESTURE_DETECTOR_H
5 * Copyright (c) 2020 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/events/pan-gesture.h>
27 #include <dali/public-api/object/property-index-ranges.h>
28 #include <dali/public-api/signals/dali-signal.h>
35 namespace Internal DALI_INTERNAL
37 class PanGestureDetector;
41 * @addtogroup dali_core_events
46 * @brief This class looks for panning (or dragging) gestures.
48 * The user will be pressing one or more fingers on an actor while they pan it.
50 * The application programmer can use this gesture detector as follows:
52 * PanGestureDetector detector = PanGestureDetector::New();
53 * detector.Attach(myActor);
54 * detector.DetectedSignal().Connect(this, &MyApplication::OnPan);
56 * // Detect pan gesture for single and double touch.
57 * detector.SetMaximumTouchesRequired(2);
64 * | %Signal Name | Method |
65 * |--------------|-----------------------|
66 * | panDetected | @ref DetectedSignal() |
68 class DALI_CORE_API PanGestureDetector : public GestureDetector
73 * @brief Enumeration for the instance of properties belonging to the PanGestureDetector class.
79 * @brief Enumeration for the instance of properties belonging to the PanGestureDetector class.
84 SCREEN_POSITION = DEFAULT_GESTURE_DETECTOR_PROPERTY_START_INDEX, ///< name "screenPosition", type Vector2 @SINCE_1_0.0
85 SCREEN_DISPLACEMENT, ///< name "screenDisplacement", type Vector2 @SINCE_1_0.0
86 SCREEN_VELOCITY, ///< name "screenVelocity", type Vector2 @SINCE_1_0.0
87 LOCAL_POSITION, ///< name "localPosition", type Vector2 @SINCE_1_0.0
88 LOCAL_DISPLACEMENT, ///< name "localDisplacement", type Vector2 @SINCE_1_0.0
89 LOCAL_VELOCITY, ///< name "localVelocity", type Vector2 @SINCE_1_0.0
90 PANNING, ///< name "panning", type bool @SINCE_1_0.0
95 typedef Signal< void ( Actor, const PanGesture& ) > DetectedSignalType; ///< Pan gesture detected signal type @SINCE_1_0.0
98 typedef std::pair< Radian, Radian > AngleThresholdPair; ///< Range of angles for a direction @SINCE_1_0.0
100 static const Radian DIRECTION_LEFT; ///< For a left pan (-PI Radians).
101 static const Radian DIRECTION_RIGHT; ///< For a right pan (0 Radians).
102 static const Radian DIRECTION_UP; ///< For an up pan (-0.5 * PI Radians).
103 static const Radian DIRECTION_DOWN; ///< For a down pan (0.5 * PI Radians).
104 static const Radian DIRECTION_HORIZONTAL; ///< For a left and right pan (PI Radians). Useful for AddDirection().
105 static const Radian DIRECTION_VERTICAL; ///< For an up and down pan (-0.5 * PI Radians). Useful for AddDirection().
107 static const Radian DEFAULT_THRESHOLD; ///< The default threshold is PI * 0.25 radians (or 45 degrees).
109 public: // Creation & Destruction
112 * @brief Creates an uninitialized PanGestureDetector; this can be initialized with PanGestureDetector::New().
114 * Calling member functions with an uninitialized PanGestureDetector handle is not allowed.
117 PanGestureDetector();
120 * @brief Creates an initialized PanGestureDetector.
123 * @return A handle to a newly allocated Dali resource
125 static PanGestureDetector New();
128 * @brief Downcasts a handle to PanGestureDetector handle.
130 * If handle points to a PanGestureDetector object, the
131 * downcast produces valid handle. If not, the returned handle is left uninitialized.
133 * @param[in] handle Handle to an object
134 * @return Handle to a PanGestureDetector object or an uninitialized handle
136 static PanGestureDetector DownCast( BaseHandle handle );
141 * This is non-virtual since derived Handle types must not contain data or virtual methods.
144 ~PanGestureDetector();
147 * @brief This copy constructor is required for (smart) pointer semantics.
150 * @param[in] handle A reference to the copied handle
152 PanGestureDetector(const PanGestureDetector& handle);
155 * @brief This assignment operator is required for (smart) pointer semantics.
158 * @param[in] rhs A reference to the copied handle
159 * @return A reference to this
161 PanGestureDetector& operator=(const PanGestureDetector& rhs);
166 * @brief This is the minimum number of touches required for the pan gesture to be detected.
169 * @param[in] minimum Minimum touches required
170 * @pre The gesture detector has been initialized.
171 * @note The default minimum is '1'.
173 void SetMinimumTouchesRequired(uint32_t minimum);
176 * @brief This is the maximum number of touches required for the pan gesture to be detected.
179 * @param[in] maximum Maximum touches required
180 * @pre The gesture detector has been initialized.
181 * @note The default maximum is '1'.
183 void SetMaximumTouchesRequired(uint32_t maximum);
188 * @brief Retrieves the minimum number of touches required for the pan gesture to be detected.
191 * @return The minimum touches required
192 * @pre The gesture detector has been initialized.
194 uint32_t GetMinimumTouchesRequired() const;
197 * @brief Retrieves the maximum number of touches required for the pan gesture to be detected.
200 * @return The maximum touches required
201 * @pre The gesture detector has been initialized.
203 uint32_t GetMaximumTouchesRequired() const;
205 public: // Directional Panning
208 * @brief The pan gesture is only emitted if the pan occurs in the direction specified by this method with a +/- threshold allowance.
210 * The angle is from -180 -> 0 -> 180 degrees (or -M_PI -> 0 -> M_PI in radians) i.e:
213 * -90.0f ( -0.5f * PI )
216 * 180.0f ( PI ) ------------- 0.0f ( 0.0f )
219 * 90.0f ( 0.5f * PI )
222 * If an angle of 0.0 degrees is specified and the threshold is 45 degrees then the acceptable
223 * direction range is from -45 to 45 degrees.
226 * @param[in] angle The angle that pan should be allowed
227 * @param[in] threshold The threshold around that angle
229 * @pre The gesture detector has been initialized.
230 * @note The angle added using this API is only checked when the gesture first starts, after that,
231 * this detector will emit the gesture regardless of what angle the pan is moving.
232 * @note The user can add as many angles as they require.
233 * @note If an angle outside the range above is given, then it is wrapped within the range, i.e.
234 * 190 degrees becomes -170 degrees and 370 degrees becomes 10 degrees.
235 * @note As long as you specify the type, you can also pass in a Dali::Degree to this method.
236 * @note If no threshold is provided, then the default threshold (PI * 0.25) is used.
237 * @note If the threshold is greater than PI, then PI will be used as the threshold.
240 void AddAngle( Radian angle, Radian threshold = DEFAULT_THRESHOLD );
243 * @brief A helper method for adding bi-directional angles where the pan should take place.
245 * In other words, if 0 is requested, then PI will also be added so that we have both left and
249 * @param[in] direction The direction of panning required
250 * @param[in] threshold The threshold
252 * @pre The gesture detector has been initialized.
254 * @note If a direction outside the range above is given, then it is wrapped within the range, i.e.
255 * 190 degrees becomes -170 degrees and 370 degrees becomes 10 degrees.
256 * @note If no threshold is provided, then the default threshold (PI * 0.25) is used.
257 * @note If the threshold is greater than PI, then PI will be used as the threshold.
258 * @note As long as you specify the type, you can also pass in a Dali::Degree to this method.
262 void AddDirection( Radian direction, Radian threshold = DEFAULT_THRESHOLD );
265 * @brief Returns the count of angles that this pan gesture detector emits a signal.
269 * @pre The gesture detector has been initialized.
271 size_t GetAngleCount() const;
274 * @brief Returns the angle by index that this pan gesture detector emits a signal.
277 * @param[in] index The angle's index
278 * @return An angle threshold pair, or a zero valued angle pair when index is invalid
279 * @pre The gesture detector has been initialized.
280 * @pre The index is less than GetAngleCount()
282 AngleThresholdPair GetAngle(size_t index) const;
285 * @brief Clears any directional angles that are used by the gesture detector.
287 * After this, the pan gesture
288 * will be emitted for a pan in ANY direction.
290 * @pre The gesture detector has been initialized.
295 * @brief Removes the angle specified from the container.
298 * @param[in] angle The angle to remove
299 * @pre The gesture detector has been initialized.
300 * @note This will only remove the first instance of the angle found from the container.
301 * @note If an angle outside the range in AddAngle() is given, then the value is wrapped within
302 * the range and that is removed.
304 void RemoveAngle( Radian angle );
307 * @brief Removes the two angles that make up the direction from the container.
310 * @param[in] direction The direction to remove
311 * @pre The gesture detector has been initialized.
312 * @note If a direction outside the range in AddAngle() is given, then the value is wrapped within
313 * the range and that is removed.
315 void RemoveDirection( Radian direction );
320 * @brief This signal is emitted when the pan gesture is detected on the attached actor.
322 * A callback of the following type may be connected:
324 * void YourCallbackName( Actor actor, const PanGesture& gesture );
327 * @return The signal to connect to
328 * @pre The gesture detector has been initialized.
330 DetectedSignalType& DetectedSignal();
332 public: // Pan Properties Setters
335 * @brief Allows setting of the pan properties that are returned in constraints.
338 * @param[in] pan The pan gesture to set
339 * @note If a normal pan is taking place, then any value set is ignored.
341 static void SetPanGestureProperties( const PanGesture& pan );
343 public: // Not intended for Application developers
347 * @brief This constructor is used by PanGestureDetector::New() methods.
350 * @param[in] internal A pointer to a newly allocated Dali resource
352 explicit DALI_INTERNAL PanGestureDetector(Internal::PanGestureDetector* internal);
363 #endif // DALI_PAN_GESTURE_DETECTOR_H