1 #ifndef DALI_TOOLKIT_ITEM_LAYOUT_H
2 #define DALI_TOOLKIT_ITEM_LAYOUT_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 <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/controls/control.h>
28 #include <dali-toolkit/public-api/enums.h>
38 * @addtogroup dali_toolkit_controls_item_view
44 typedef IntrusivePtr<ItemLayout> ItemLayoutPtr; ///< Pointer to a Dali::Toolkit::ItemLayout object @SINCE_1_0.0
47 * @brief A support class for managing ranges of items.
53 * @brief Creates a range of item identifiers.
56 * @param[in] beginItem The first item within the range
57 * @param[in] endItem The past-the-end item
59 ItemRange(unsigned int beginItem, unsigned int endItem)
66 * @brief Copy Constructor.
69 * @param[in] copy ItemRange we should copy from
71 ItemRange(const ItemRange& copy)
78 * @brief Assignment operator.
81 * @param[in] range The Range to assign from
82 * @return The updated range
84 ItemRange& operator=(const ItemRange& range)
95 * @brief Tests whether an item is within the range.
98 * @param[in] itemId The item identifier
99 * @return true if the item is within the range
101 bool Within(unsigned int itemId)
103 return itemId >= begin &&
108 * @brief Creates the intersection of two ranges.
111 * @param[in] second The second range
112 * @return The intersection
114 ItemRange Intersection(const ItemRange& second)
116 ItemRange intersection(0u, 0u);
118 // If the ranges intersect
119 if((begin < second.end && end > second.begin) ||
120 (second.begin < end && second.end > begin))
122 intersection.begin = std::max(begin, second.begin);
123 intersection.end = std::min(end, second.end);
129 unsigned int begin; ///< The start of the range
130 unsigned int end; ///< The end of the range
134 * @brief An ItemLayout describes the constraints which are imposed on items in the layout.
136 * - Potentially visible items are represented by Actors, created for ItemView by the ItemFactory.
137 * - Constraints are applied after ItemView activates a layout.
139 * An ItemLayout also describes the direction of input gestures, used to scroll through the layout.
140 * Whilst scrolling, the layout provides a range of items that are within a layout-area (3D bounding volume).
143 class DALI_TOOLKIT_API ItemLayout : public RefObject
146 class Extension; ///< Forward declare future extension interface
149 * @brief Virtual destructor.
152 virtual ~ItemLayout();
155 * @brief Set the orientation of the layout.
158 * @param[in] orientation The orientation of the layout.
160 void SetOrientation(ControlOrientation::Type orientation);
163 * @brief Query the orientation of the layout.
166 * @return the orientation of the layout.
168 ControlOrientation::Type GetOrientation() const;
171 * @brief Apply the layout Properties.
173 * @param[in] properties The properties the layout.
175 void SetLayoutProperties(const Property::Map& properties);
178 * @brief Get the layout Properties.
180 * @return the property of the layout.
182 Property::Map GetLayoutProperties();
185 * @brief Retrieve the target size of an item in the layout.
187 * This will return the default size for the layout unless overridden by calling SetItemSize().
190 * @param[in] itemId The ID of an item in the layout.
191 * @param[in] layoutSize The layout size
192 * @param[out] itemSize The target size of an item.
193 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
194 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
196 void GetItemSize(unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize) const;
199 * @brief Overrides the default size for the layout.
202 * @param[in] itemSize The size of each item.
204 void SetItemSize(const Vector3& itemSize);
207 * @brief Query the minimum valid layout position; this is a negative value.
209 * When scrolling, the first item will move within the range 0 to GetMinimumLayoutPosition().
211 * @param[in] numberOfItems The current number of items in the layout.
212 * @param[in] layoutSize The size of the layout area.
213 * @return The minimum layout position.
215 virtual float GetMinimumLayoutPosition(unsigned int numberOfItems, Vector3 layoutSize) const = 0;
218 * @brief Query the closest anchor position for the given layout position.
220 * This anchor position is the position where all the items in the layout are aligned to
221 * their rounded layout positions in integer.
223 * @param[in] layoutPosition The layout position.
224 * @return The closest anchor position for the given layout position.
226 virtual float GetClosestAnchorPosition(float layoutPosition) const = 0;
229 * @brief Query the layout position for the first item in the layout to move to when the layout
230 * needs to scroll to a particular item.
233 * @param[in] itemId The ID of an item in the layout.
234 * @return The layout position for the first item in the layout to move to.
236 virtual float GetItemScrollToPosition(unsigned int itemId) const = 0;
239 * @brief Query the items within a given layout-area.
242 * @param[in] firstItemPosition The layout-position of the first item in the layout.
243 * @param[in] layoutSize The size of the layout area.
244 * @return The ID of the first & last visible item.
246 virtual ItemRange GetItemsWithinArea(float firstItemPosition, Vector3 layoutSize) const = 0;
249 * @brief Get the closest layout position to bring an item onto the screen.
251 * If the item is already fully on the screen this function will
252 * return the current layout position.
254 * This function is used by systems such as KeyboardFocusManager to
255 * bring the next focusable item into view and all layout
256 * implementations should provide their own version of this function
257 * to ensure proper functionality of internal toolkit systems.
260 * @param[in] itemID id of the item to bring within the viewable screen area
261 * @param[in] currentLayoutPosition the current layout position of the item view instance
262 * @param[in] layoutSize the current size of the item view instance
263 * @return The layout position
265 virtual float GetClosestOnScreenLayoutPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize);
268 * @brief Query the number of items that should be reserved, for scrolling purposes.
271 * @param[in] layoutSize The size of the layout area.
272 * @return The number of extra items. ItemView will populate itself with actors within the layout-area
273 * (see GetItemsWithinArea), plus this number of additional items on either-side.
275 virtual unsigned int GetReserveItemCount(Vector3 layoutSize) const = 0;
278 * @brief Retrieve the default size of an item in the layout.
281 * @param[in] itemId The ID of an item in the layout.
282 * @param[in] layoutSize The layout size
283 * @param[out] itemSize The target size of an item.
284 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
285 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
287 virtual void GetDefaultItemSize(unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize) const = 0;
290 * @brief Query the scroll direction of the layout.
292 * When an input gesture follows this direction, the layout-position of items will be increased.
293 * If the input gesture points in the opposite direction, then the layout-positions will decrease.
295 * @return The scroll direction in degrees.
297 virtual Degree GetScrollDirection() const = 0;
300 * @brief Query the scroll speed factor of the layout while dragging.
302 * This factor is used by the layout to customise its scroll speed while dragging.
303 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
304 * and the layout position of the actors in ItemView will be moved by this result.
305 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
306 * position of actors will be moved by 1.
307 * Therefore, the bigger the factor is, the faster the scroll speed will be.
310 * @return The scroll speed factor of the layout.
312 virtual float GetScrollSpeedFactor() const = 0;
315 * @brief Query the maximum swipe speed in pixels per second.
317 * Swipe gestures will be clamped when exceeding this speed limit.
319 * @return speed The maximum swipe speed.
321 virtual float GetMaximumSwipeSpeed() const = 0;
324 * @brief Get the duration of the flick animation in second.
326 * This is the time taken to animate each
327 * item to its next layout position (e.g. from 1.0 to 2.0) when a flick animation is triggered
328 * by a swipe gesture.
330 * @return The duration of the flick animation.
332 virtual float GetItemFlickAnimationDuration() const = 0;
335 * @brief Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.
338 * @param[in] itemID The current focused item
339 * @param[in] maxItems The maximum number of items in the list
340 * @param[in] direction The directional key pressed on the keyboard
341 * @param[in] loopEnabled Whether the KeyboardFocusManager is set to wrap around between first and last item
342 * @return The next item ID.
344 virtual int GetNextFocusItemID(int itemID, int maxItems, Dali::Toolkit::Control::KeyboardFocus::Direction direction, bool loopEnabled);
347 * @brief Query the flick speed factor of the layout while swipping.
349 * This factor is used by the layout to customise its scroll speed while swiping.
350 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
351 * and the layout position of the actors in ItemView will be moved by this result.
352 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
353 * position of actors will be moved by 1.
354 * Therefore, the bigger the factor is, the faster the flick speed will be.
357 * @return The scroll speed factor of the layout.
359 virtual float GetFlickSpeedFactor() const;
362 * @brief Applies constraints defined by the layout to an actor.
364 * @param[in] actor The actor to constrain.
365 * @param[in] itemId The ID of the item represented by the actor.
366 * @param[in] layoutSize The current size of the item view instance.
367 * @param[in] itemViewActor The item view instance which requests the application of constraints.
369 virtual void ApplyConstraints(Actor& actor, const int itemId, const Vector3& layoutSize, const Actor& itemViewActor) = 0;
372 * @brief Gets the position of a given item
375 * @param[in] itemID The id of the item we want to get its position
376 * @param[in] currentLayoutPosition The current layout position of the item view instance
377 * @param[in] layoutSize The current size of the item view instance
378 * @return The item position (x,y,z)
380 virtual Vector3 GetItemPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize) const = 0;
383 * @brief Retrieve the extension for this layout.
386 * @return The extension if available, NULL otherwise
388 virtual Extension* GetExtension()
395 * @brief Create a new ItemLayout; Only derived versions are instantiatable.
402 * @brief Don't allow copy constructor
405 ItemLayout(const ItemLayout& handle);
408 * @brief Don't allow copy operator
411 ItemLayout& operator=(const ItemLayout& handle);
421 } // namespace Toolkit
425 #endif // DALI_TOOLKIT_ITEM_LAYOUT_H