1 #ifndef DALI_TOOLKIT_ITEM_LAYOUT_H
2 #define DALI_TOOLKIT_ITEM_LAYOUT_H
5 * Copyright (c) 2019 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 <dali/public-api/animation/alpha-function.h>
23 #include <dali/public-api/object/property-key.h>
24 #include <dali/public-api/object/property-map.h>
27 #include <dali-toolkit/public-api/enums.h>
28 #include <dali-toolkit/public-api/controls/control.h>
39 * @addtogroup dali_toolkit_controls_item_view
45 typedef IntrusivePtr<ItemLayout> ItemLayoutPtr; ///< Pointer to a Dali::Toolkit::ItemLayout object @SINCE_1_0.0
48 * @brief A support class for managing ranges of items.
54 * @brief Creates a range of item identifiers.
57 * @param[in] beginItem The first item within the range
58 * @param[in] endItem The past-the-end item
60 ItemRange(unsigned int beginItem, unsigned int endItem)
67 * @brief Copy Constructor.
70 * @param[in] copy ItemRange we should copy from
72 ItemRange(const ItemRange& copy)
79 * @brief Assignment operator.
82 * @param[in] range The Range to assign from
83 * @return The updated range
85 ItemRange& operator=(const ItemRange& range)
96 * @brief Tests whether an item is within the range.
99 * @param[in] itemId The item identifier
100 * @return true if the item is within the range
102 bool Within(unsigned int itemId)
104 return itemId >= begin &&
109 * @brief Creates the intersection of two ranges.
112 * @param[in] second The second range
113 * @return The intersection
115 ItemRange Intersection(const ItemRange& second)
117 ItemRange intersection(0u, 0u);
119 // If the ranges intersect
120 if ( (begin < second.end && end > second.begin) ||
121 (second.begin < end && second.end > begin) )
123 intersection.begin = std::max(begin, second.begin);
124 intersection.end = std::min(end, second.end);
130 unsigned int begin; ///< The start of the range
131 unsigned int end; ///< The end of the range
135 * @brief An ItemLayout describes the constraints which are imposed on items in the layout.
137 * - Potentially visible items are represented by Actors, created for ItemView by the ItemFactory.
138 * - Constraints are applied after ItemView activates a layout.
140 * An ItemLayout also describes the direction of input gestures, used to scroll through the layout.
141 * Whilst scrolling, the layout provides a range of items that are within a layout-area (3D bounding volume).
144 class DALI_TOOLKIT_API ItemLayout : public RefObject
148 class Extension; ///< Forward declare future extension interface
151 * @brief Virtual destructor.
154 virtual ~ItemLayout();
157 * @brief Set the orientation of the layout.
160 * @param[in] orientation The orientation of the layout.
162 void SetOrientation(ControlOrientation::Type orientation);
165 * @brief Query the orientation of the layout.
168 * @return the orientation of the layout.
170 ControlOrientation::Type GetOrientation() const;
173 * @brief Apply the layout Properties.
175 * @param[in] properties The properties the layout.
177 void SetLayoutProperties(const Property::Map& properties);
180 * @brief Get the layout Properties.
182 * @return the property of the layout.
184 Property::Map GetLayoutProperties();
187 * @brief Retrieve the target size of an item in the layout.
189 * This will return the default size for the layout unless overridden by calling SetItemSize().
192 * @param[in] itemId The ID of an item in the layout.
193 * @param[in] layoutSize The layout size
194 * @param[out] itemSize The target size of an item.
195 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
196 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
198 void GetItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const;
201 * @brief Overrides the default size for the layout.
204 * @param[in] itemSize The size of each item.
206 void SetItemSize( const Vector3& itemSize );
209 * @brief Query the minimum valid layout position; this is a negative value.
211 * When scrolling, the first item will move within the range 0 to GetMinimumLayoutPosition().
213 * @param[in] numberOfItems The current number of items in the layout.
214 * @param[in] layoutSize The size of the layout area.
215 * @return The minimum layout position.
217 virtual float GetMinimumLayoutPosition(unsigned int numberOfItems, Vector3 layoutSize) const = 0;
220 * @brief Query the closest anchor position for the given layout position.
222 * This anchor position is the position where all the items in the layout are aligned to
223 * their rounded layout positions in integer.
225 * @param[in] layoutPosition The layout position.
226 * @return The closest anchor position for the given layout position.
228 virtual float GetClosestAnchorPosition(float layoutPosition) const = 0;
231 * @brief Query the layout position for the first item in the layout to move to when the layout
232 * needs to scroll to a particular item.
235 * @param[in] itemId The ID of an item in the layout.
236 * @return The layout position for the first item in the layout to move to.
238 virtual float GetItemScrollToPosition(unsigned int itemId) const = 0;
241 * @brief Query the items within a given layout-area.
244 * @param[in] firstItemPosition The layout-position of the first item in the layout.
245 * @param[in] layoutSize The size of the layout area.
246 * @return The ID of the first & last visible item.
248 virtual ItemRange GetItemsWithinArea(float firstItemPosition, Vector3 layoutSize) const = 0;
251 * @brief Get the closest layout position to bring an item onto the screen.
253 * If the item is already fully on the screen this function will
254 * return the current layout position.
256 * This function is used by systems such as KeyboardFocusManager to
257 * bring the next focusable item into view and all layout
258 * implementations should provide their own version of this function
259 * to ensure proper functionality of internal toolkit systems.
262 * @param[in] itemID id of the item to bring within the viewable screen area
263 * @param[in] currentLayoutPosition the current layout position of the item view instance
264 * @param[in] layoutSize the current size of the item view instance
265 * @return The layout position
267 virtual float GetClosestOnScreenLayoutPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize);
270 * @brief Query the number of items that should be reserved, for scrolling purposes.
273 * @param[in] layoutSize The size of the layout area.
274 * @return The number of extra items. ItemView will populate itself with actors within the layout-area
275 * (see GetItemsWithinArea), plus this number of additional items on either-side.
277 virtual unsigned int GetReserveItemCount(Vector3 layoutSize) const = 0;
280 * @brief Retrieve the default size of an item in the layout.
283 * @param[in] itemId The ID of an item in the layout.
284 * @param[in] layoutSize The layout size
285 * @param[out] itemSize The target size of an item.
286 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
287 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
289 virtual void GetDefaultItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const = 0;
292 * @brief Query the scroll direction of the layout.
294 * When an input gesture follows this direction, the layout-position of items will be increased.
295 * If the input gesture points in the opposite direction, then the layout-positions will decrease.
297 * @return The scroll direction in degrees.
299 virtual Degree GetScrollDirection() const = 0;
302 * @brief Query the scroll speed factor of the layout while dragging.
304 * This factor is used by the layout to customise its scroll speed while dragging.
305 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
306 * and the layout position of the actors in ItemView will be moved by this result.
307 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
308 * position of actors will be moved by 1.
309 * Therefore, the bigger the factor is, the faster the scroll speed will be.
312 * @return The scroll speed factor of the layout.
314 virtual float GetScrollSpeedFactor() const = 0;
317 * @brief Query the maximum swipe speed in pixels per second.
319 * Swipe gestures will be clamped when exceeding this speed limit.
321 * @return speed The maximum swipe speed.
323 virtual float GetMaximumSwipeSpeed() const = 0;
326 * @brief Get the duration of the flick animation in second.
328 * This is the time taken to animate each
329 * item to its next layout position (e.g. from 1.0 to 2.0) when a flick animation is triggered
330 * by a swipe gesture.
332 * @return The duration of the flick animation.
334 virtual float GetItemFlickAnimationDuration() const = 0;
337 * @brief Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.
340 * @param[in] itemID The current focused item
341 * @param[in] maxItems The maximum number of items in the list
342 * @param[in] direction The directional key pressed on the keyboard
343 * @param[in] loopEnabled Whether the KeyboardFocusManager is set to wrap around between first and last item
344 * @return The next item ID.
346 virtual int GetNextFocusItemID(int itemID, int maxItems, Dali::Toolkit::Control::KeyboardFocus::Direction direction, bool loopEnabled);
349 * @brief Query the flick speed factor of the layout while swipping.
351 * This factor is used by the layout to customise its scroll speed while swiping.
352 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
353 * and the layout position of the actors in ItemView will be moved by this result.
354 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
355 * position of actors will be moved by 1.
356 * Therefore, the bigger the factor is, the faster the flick speed will be.
359 * @return The scroll speed factor of the layout.
361 virtual float GetFlickSpeedFactor() const;
364 * @brief Applies constraints defined by the layout to an actor.
366 * @param[in] actor The actor to constrain.
367 * @param[in] itemId The ID of the item represented by the actor.
368 * @param[in] layoutSize The current size of the item view instance.
369 * @param[in] itemViewActor The item view instance which requests the application of constraints.
371 virtual void ApplyConstraints( Actor& actor, const int itemId, const Vector3& layoutSize, const Actor& itemViewActor ) = 0;
374 * @brief Gets the position of a given item
377 * @param[in] itemID The id of the item we want to get its position
378 * @param[in] currentLayoutPosition The current layout position of the item view instance
379 * @param[in] layoutSize The current size of the item view instance
380 * @return The item position (x,y,z)
382 virtual Vector3 GetItemPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize) const = 0;
385 * @brief Retrieve the extension for this layout.
388 * @return The extension if available, NULL otherwise
390 virtual Extension* GetExtension()
398 * @brief Create a new ItemLayout; Only derived versions are instantiatable.
406 * @brief Don't allow copy constructor
409 ItemLayout( const ItemLayout& handle );
412 * @brief Don't allow copy operator
415 ItemLayout& operator=( const ItemLayout& handle );
426 } // namespace Toolkit
430 #endif // DALI_TOOLKIT_ITEM_LAYOUT_H