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
43 * @brief A support class for managing ranges of items.
48 * @brief Create a range of item identifiers.
50 * @param[in] beginItem The first item within the range.
51 * @param[in] endItem The past-the-end item.
53 ItemRange(unsigned int beginItem, unsigned int endItem)
60 * @brief Copy Constructor.
62 * @param[in] copy ItemRange we should copy from.
64 ItemRange(const ItemRange& copy)
71 * @brief Assignment operator.
73 * @param[in] range The Range to assign from.
74 * @return The updated range.
76 ItemRange& operator=(const ItemRange& range)
84 * @brief Test whether an item is within the range.
86 * @param[in] itemId The item identifier.
87 * @return True if the item is within the range.
89 bool Within(unsigned int itemId)
91 return itemId >= begin &&
96 * @brief Create the intersection of two ranges.
98 * @param[in] second The second range.
99 * @return The intersection.
101 ItemRange Intersection(const ItemRange& second)
103 ItemRange intersection(0u, 0u);
105 // If the ranges intersect
106 if ( (begin < second.end && end > second.begin) ||
107 (second.begin < end && second.end > begin) )
109 intersection.begin = std::max(begin, second.begin);
110 intersection.end = std::min(end, second.end);
116 unsigned int begin; ///< The start of the range
117 unsigned int end; ///< The end of the range
121 * @brief An ItemLayout describes the constraints which are imposed on items in the layout.
123 * - Potentially visible items are represented by Actors, created for ItemView by the ItemFactory.
124 * - Constraints are applied after ItemView activates a layout.
126 * An ItemLayout also describes the direction of input gestures, used to scroll through the layout.
127 * Whilst scrolling, the layout provides a range of items that are within a layout-area (3D bounding volume).
129 class DALI_IMPORT_API ItemLayout : public RefObject
133 class Extension; ///< Forward declare future extension interface
136 * @brief Virtual destructor.
138 DALI_IMPORT_API virtual ~ItemLayout();
141 * @brief Set the orientation of the layout.
143 * @param[in] orientation The orientation of the layout.
145 DALI_IMPORT_API void SetOrientation(ControlOrientation::Type orientation);
148 * @brief Query the orientation of the layout.
150 * @return the orientation of the layout.
152 DALI_IMPORT_API ControlOrientation::Type GetOrientation() const;
155 * @brief Retrieve the target size of an item in the layout.
157 * This will return the default size for the layout unless overridden by calling SetItemSize().
159 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
160 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
161 * @param[in] itemId The ID of an item in the layout.
162 * @param[in] layoutSize The layout size
163 * @param[out] itemSize The target size of an item.
165 DALI_IMPORT_API void GetItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const;
168 * @brief Overrides the default size for the layout.
170 * @param[in] itemSize The size of each item.
172 DALI_IMPORT_API void SetItemSize( const Vector3& itemSize );
175 * @brief Query the minimum valid layout position; this is a negative value.
177 * When scrolling, the first item will move within the range 0 to GetMinimumLayoutPosition().
178 * @param[in] numberOfItems The current number of items in the layout.
179 * @param[in] layoutSize The size of the layout area.
180 * @return The minimum layout position.
182 virtual float GetMinimumLayoutPosition(unsigned int numberOfItems, Vector3 layoutSize) const = 0;
185 * @brief Query the closest anchor position for the given layout position.
187 * This anchor position is the position where all the items in the layout are aligned to
188 * their rounded layout positions in integer.
189 * @param[in] layoutPosition The layout position.
190 * @return The closest anchor position for the given layout position.
192 virtual float GetClosestAnchorPosition(float layoutPosition) const = 0;
195 * @brief Query the layout position for the first item in the layout to move to when the layout
196 * needs to scroll to a particular item.
198 * @param[in] itemId The ID of an item in the layout.
199 * @return The layout position for the first item in the layout to move to.
201 virtual float GetItemScrollToPosition(unsigned int itemId) const = 0;
204 * @brief Query the items within a given layout-area.
206 * @param[in] firstItemPosition The layout-position of the first item in the layout.
207 * @param[in] layoutSize The size of the layout area.
208 * @return The ID of the first & last visible item.
210 virtual ItemRange GetItemsWithinArea(float firstItemPosition, Vector3 layoutSize) const = 0;
213 * @brief Get the closest layout position to bring an item onto the screen.
215 * If the item is already fully on the screen this function will
216 * return the current layout position.
218 * This function is used by systems such as KeyboardFocusManager to
219 * bring the next focusable item into view and all layout
220 * implementations should provide their own version of this function
221 * to ensure proper functionality of internal toolkit systems.
223 * @param[in] itemID id of the item to bring within the viewable screen area
224 * @param[in] currentLayoutPosition the current layout position of the item view instance
225 * @param[in] layoutSize the current size of the item view instance
226 * @return The layout position
228 DALI_IMPORT_API virtual float GetClosestOnScreenLayoutPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize);
231 * @brief Query the number of items that should be reserved, for scrolling purposes.
233 * @param[in] layoutSize The size of the layout area.
234 * @return The number of extra items. ItemView will populate itself with actors within the layout-area
235 * (see GetItemsWithinArea), plus this number of additional items on either-side.
237 virtual unsigned int GetReserveItemCount(Vector3 layoutSize) const = 0;
240 * @brief Retrieve the default size of an item in the layout.
242 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
243 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
244 * @param[in] itemId The ID of an item in the layout.
245 * @param[in] layoutSize The layout size
246 * @param[out] itemSize The target size of an item.
248 virtual void GetDefaultItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const = 0;
251 * @brief Query the scroll direction of the layout.
253 * When an input gesture follows this direction, the layout-position of items will be increased.
254 * If the input gesture points in the opposite direction, then the layout-positions will decrease.
255 * @return The scroll direction in degrees.
257 virtual Degree GetScrollDirection() const = 0;
260 * @brief Query the scroll speed factor of the layout while dragging.
262 * This factor is used by the layout to customise its scroll speed while dragging.
263 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
264 * and the layout position of the actors in ItemView will be moved by this result.
265 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
266 * position of actors will be moved by 1.
267 * Therefore, the bigger the factor is, the faster the scroll speed will be.
269 * @return The scroll speed factor of the layout.
271 virtual float GetScrollSpeedFactor() const = 0;
274 * @brief Query the maximum swipe speed in pixels per second.
276 * Swipe gestures will be clamped when exceeding this speed limit.
277 * @return speed The maximum swipe speed.
279 virtual float GetMaximumSwipeSpeed() const = 0;
282 * @brief Get the duration of the flick animation in second.
284 * This is the time taken to animate each
285 * item to its next layout position (e.g. from 1.0 to 2.0) when a flick animation is triggered
286 * by a swipe gesture.
287 * @return The duration of the flick animation.
289 virtual float GetItemFlickAnimationDuration() const = 0;
292 * @brief Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.
294 * @param[in] itemID The current focused item
295 * @param[in] maxItems The maximum number of items in the list
296 * @param[in] direction The directional key pressed on the keyboard
297 * @param[in] loopEnabled Whether the KeyboardFocusManager is set to wrap around between first and last item
298 * @return The next item ID.
300 DALI_IMPORT_API virtual int GetNextFocusItemID(int itemID, int maxItems, Dali::Toolkit::Control::KeyboardFocus::Direction direction, bool loopEnabled);
303 * @brief Query the flick speed factor of the layout while swipping.
305 * This factor is used by the layout to customise its scroll speed while swiping.
306 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
307 * and the layout position of the actors in ItemView will be moved by this result.
308 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
309 * position of actors will be moved by 1.
310 * Therefore, the bigger the factor is, the faster the flick speed will be.
312 * @return The scroll speed factor of the layout.
314 DALI_IMPORT_API virtual float GetFlickSpeedFactor() const;
317 * @brief Applies constraints defined by the layout to an actor.
319 * @param[in] actor The actor to constrain.
320 * @param[in] itemId The ID of the item represented by the actor.
321 * @param[in] layoutSize the current size of the item view instance.
322 * @param[in] itemViewActor The item view instance which requests the application of constraints.
324 DALI_IMPORT_API virtual void ApplyConstraints( Actor& actor, const int itemId, const Vector3& layoutSize, const Actor& itemViewActor ) = 0;
327 * @brief Gets the position of a given item
329 * @param[in] itemID id of the item we want to get its position
330 * @param[in] currentLayoutPosition the current layout position of the item view instance
331 * @param[in] layoutSize the current size of the item view instance
332 * @return The item position (x,y,z)
334 DALI_IMPORT_API virtual Vector3 GetItemPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize) const = 0;
337 * Retrieve the extension for this layout.
339 * @return The extension if available, NULL otherwise
341 virtual Extension* GetExtension()
349 * @brief Create a new ItemLayout; Only derived versions are instantiatable.
351 DALI_IMPORT_API ItemLayout();
356 * Don't allow copy constructor
358 ItemLayout( const ItemLayout& handle );
361 * Don't allow copy operator
363 ItemLayout& operator=( const ItemLayout& handle );
374 } // namespace Toolkit
378 #endif // __DALI_TOOLKIT_ITEM_LAYOUT_H__