1 #ifndef __DALI_TOOLKIT_ITEM_LAYOUT_H__
2 #define __DALI_TOOLKIT_ITEM_LAYOUT_H__
5 * Copyright (c) 2015 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>
25 #include <dali-toolkit/public-api/enums.h>
26 #include <dali-toolkit/public-api/controls/control.h>
34 * @addtogroup dali_toolkit_controls_item_view
40 typedef IntrusivePtr<ItemLayout> ItemLayoutPtr; ///< Pointer to a Dali::Toolkit::ItemLayout object @SINCE_1_0.0
43 * @brief A support class for managing ranges of items.
49 * @brief Create a range of item identifiers.
52 * @param[in] beginItem The first item within the range.
53 * @param[in] endItem The past-the-end item.
55 ItemRange(unsigned int beginItem, unsigned int endItem)
62 * @brief Copy Constructor.
65 * @param[in] copy ItemRange we should copy from.
67 ItemRange(const ItemRange& copy)
74 * @brief Assignment operator.
77 * @param[in] range The Range to assign from.
78 * @return The updated range.
80 ItemRange& operator=(const ItemRange& range)
88 * @brief Test whether an item is within the range.
91 * @param[in] itemId The item identifier.
92 * @return True if the item is within the range.
94 bool Within(unsigned int itemId)
96 return itemId >= begin &&
101 * @brief Create the intersection of two ranges.
104 * @param[in] second The second range.
105 * @return The intersection.
107 ItemRange Intersection(const ItemRange& second)
109 ItemRange intersection(0u, 0u);
111 // If the ranges intersect
112 if ( (begin < second.end && end > second.begin) ||
113 (second.begin < end && second.end > begin) )
115 intersection.begin = std::max(begin, second.begin);
116 intersection.end = std::min(end, second.end);
122 unsigned int begin; ///< The start of the range
123 unsigned int end; ///< The end of the range
127 * @brief An ItemLayout describes the constraints which are imposed on items in the layout.
129 * - Potentially visible items are represented by Actors, created for ItemView by the ItemFactory.
130 * - Constraints are applied after ItemView activates a layout.
132 * An ItemLayout also describes the direction of input gestures, used to scroll through the layout.
133 * Whilst scrolling, the layout provides a range of items that are within a layout-area (3D bounding volume).
136 class DALI_IMPORT_API ItemLayout : public RefObject
140 class Extension; ///< Forward declare future extension interface
143 * @brief Virtual destructor.
146 DALI_IMPORT_API virtual ~ItemLayout();
149 * @brief Set the orientation of the layout.
152 * @param[in] orientation The orientation of the layout.
154 DALI_IMPORT_API void SetOrientation(ControlOrientation::Type orientation);
157 * @brief Query the orientation of the layout.
160 * @return the orientation of the layout.
162 DALI_IMPORT_API ControlOrientation::Type GetOrientation() const;
165 * @brief Retrieve the target size of an item in the layout.
167 * This will return the default size for the layout unless overridden by calling SetItemSize().
170 * @param[in] itemId The ID of an item in the layout.
171 * @param[in] layoutSize The layout size
172 * @param[out] itemSize The target size of an item.
173 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
174 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
176 DALI_IMPORT_API void GetItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const;
179 * @brief Overrides the default size for the layout.
182 * @param[in] itemSize The size of each item.
184 DALI_IMPORT_API void SetItemSize( const Vector3& itemSize );
187 * @brief Query the minimum valid layout position; this is a negative value.
189 * When scrolling, the first item will move within the range 0 to GetMinimumLayoutPosition().
191 * @param[in] numberOfItems The current number of items in the layout.
192 * @param[in] layoutSize The size of the layout area.
193 * @return The minimum layout position.
195 virtual float GetMinimumLayoutPosition(unsigned int numberOfItems, Vector3 layoutSize) const = 0;
198 * @brief Query the closest anchor position for the given layout position.
200 * This anchor position is the position where all the items in the layout are aligned to
201 * their rounded layout positions in integer.
203 * @param[in] layoutPosition The layout position.
204 * @return The closest anchor position for the given layout position.
206 virtual float GetClosestAnchorPosition(float layoutPosition) const = 0;
209 * @brief Query the layout position for the first item in the layout to move to when the layout
210 * needs to scroll to a particular item.
213 * @param[in] itemId The ID of an item in the layout.
214 * @return The layout position for the first item in the layout to move to.
216 virtual float GetItemScrollToPosition(unsigned int itemId) const = 0;
219 * @brief Query the items within a given layout-area.
222 * @param[in] firstItemPosition The layout-position of the first item in the layout.
223 * @param[in] layoutSize The size of the layout area.
224 * @return The ID of the first & last visible item.
226 virtual ItemRange GetItemsWithinArea(float firstItemPosition, Vector3 layoutSize) const = 0;
229 * @brief Get the closest layout position to bring an item onto the screen.
231 * If the item is already fully on the screen this function will
232 * return the current layout position.
234 * This function is used by systems such as KeyboardFocusManager to
235 * bring the next focusable item into view and all layout
236 * implementations should provide their own version of this function
237 * to ensure proper functionality of internal toolkit systems.
240 * @param[in] itemID id of the item to bring within the viewable screen area
241 * @param[in] currentLayoutPosition the current layout position of the item view instance
242 * @param[in] layoutSize the current size of the item view instance
243 * @return The layout position
245 DALI_IMPORT_API virtual float GetClosestOnScreenLayoutPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize);
248 * @brief Query the number of items that should be reserved, for scrolling purposes.
251 * @param[in] layoutSize The size of the layout area.
252 * @return The number of extra items. ItemView will populate itself with actors within the layout-area
253 * (see GetItemsWithinArea), plus this number of additional items on either-side.
255 virtual unsigned int GetReserveItemCount(Vector3 layoutSize) const = 0;
258 * @brief Retrieve the default size of an item in the layout.
261 * @param[in] itemId The ID of an item in the layout.
262 * @param[in] layoutSize The layout size
263 * @param[out] itemSize The target size of an item.
264 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
265 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
267 virtual void GetDefaultItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const = 0;
270 * @brief Query the scroll direction of the layout.
272 * When an input gesture follows this direction, the layout-position of items will be increased.
273 * If the input gesture points in the opposite direction, then the layout-positions will decrease.
275 * @return The scroll direction in degrees.
277 virtual Degree GetScrollDirection() const = 0;
280 * @brief Query the scroll speed factor of the layout while dragging.
282 * This factor is used by the layout to customise its scroll speed while dragging.
283 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
284 * and the layout position of the actors in ItemView will be moved by this result.
285 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
286 * position of actors will be moved by 1.
287 * Therefore, the bigger the factor is, the faster the scroll speed will be.
290 * @return The scroll speed factor of the layout.
292 virtual float GetScrollSpeedFactor() const = 0;
295 * @brief Query the maximum swipe speed in pixels per second.
297 * Swipe gestures will be clamped when exceeding this speed limit.
299 * @return speed The maximum swipe speed.
301 virtual float GetMaximumSwipeSpeed() const = 0;
304 * @brief Get the duration of the flick animation in second.
306 * This is the time taken to animate each
307 * item to its next layout position (e.g. from 1.0 to 2.0) when a flick animation is triggered
308 * by a swipe gesture.
310 * @return The duration of the flick animation.
312 virtual float GetItemFlickAnimationDuration() const = 0;
315 * @brief Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.
318 * @param[in] itemID The current focused item
319 * @param[in] maxItems The maximum number of items in the list
320 * @param[in] direction The directional key pressed on the keyboard
321 * @param[in] loopEnabled Whether the KeyboardFocusManager is set to wrap around between first and last item
322 * @return The next item ID.
324 DALI_IMPORT_API virtual int GetNextFocusItemID(int itemID, int maxItems, Dali::Toolkit::Control::KeyboardFocus::Direction direction, bool loopEnabled);
327 * @brief Query the flick speed factor of the layout while swipping.
329 * This factor is used by the layout to customise its scroll speed while swiping.
330 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
331 * and the layout position of the actors in ItemView will be moved by this result.
332 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
333 * position of actors will be moved by 1.
334 * Therefore, the bigger the factor is, the faster the flick speed will be.
337 * @return The scroll speed factor of the layout.
339 DALI_IMPORT_API virtual float GetFlickSpeedFactor() const;
342 * @brief Applies constraints defined by the layout to an actor.
344 * @param[in] actor The actor to constrain.
345 * @param[in] itemId The ID of the item represented by the actor.
346 * @param[in] layoutSize The current size of the item view instance.
347 * @param[in] itemViewActor The item view instance which requests the application of constraints.
349 DALI_IMPORT_API virtual void ApplyConstraints( Actor& actor, const int itemId, const Vector3& layoutSize, const Actor& itemViewActor ) = 0;
352 * @brief Gets the position of a given item
355 * @param[in] itemID The id of the item we want to get its position
356 * @param[in] currentLayoutPosition The current layout position of the item view instance
357 * @param[in] layoutSize The current size of the item view instance
358 * @return The item position (x,y,z)
360 DALI_IMPORT_API virtual Vector3 GetItemPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize) const = 0;
363 * @brief Retrieve the extension for this layout.
366 * @return The extension if available, NULL otherwise
368 virtual Extension* GetExtension()
376 * @brief Create a new ItemLayout; Only derived versions are instantiatable.
379 DALI_IMPORT_API ItemLayout();
384 * @brief Don't allow copy constructor
387 ItemLayout( const ItemLayout& handle );
390 * @brief Don't allow copy operator
393 ItemLayout& operator=( const ItemLayout& handle );
404 } // namespace Toolkit
408 #endif // __DALI_TOOLKIT_ITEM_LAYOUT_H__