1 #ifndef __DALI_TOOLKIT_ITEM_LAYOUT_H__
2 #define __DALI_TOOLKIT_ITEM_LAYOUT_H__
5 * Copyright (c) 2016 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)
91 * @brief Test whether an item is within the range.
94 * @param[in] itemId The item identifier.
95 * @return True if the item is within the range.
97 bool Within(unsigned int itemId)
99 return itemId >= begin &&
104 * @brief Create the intersection of two ranges.
107 * @param[in] second The second range.
108 * @return The intersection.
110 ItemRange Intersection(const ItemRange& second)
112 ItemRange intersection(0u, 0u);
114 // If the ranges intersect
115 if ( (begin < second.end && end > second.begin) ||
116 (second.begin < end && second.end > begin) )
118 intersection.begin = std::max(begin, second.begin);
119 intersection.end = std::min(end, second.end);
125 unsigned int begin; ///< The start of the range
126 unsigned int end; ///< The end of the range
130 * @brief An ItemLayout describes the constraints which are imposed on items in the layout.
132 * - Potentially visible items are represented by Actors, created for ItemView by the ItemFactory.
133 * - Constraints are applied after ItemView activates a layout.
135 * An ItemLayout also describes the direction of input gestures, used to scroll through the layout.
136 * Whilst scrolling, the layout provides a range of items that are within a layout-area (3D bounding volume).
139 class DALI_IMPORT_API ItemLayout : public RefObject
143 class Extension; ///< Forward declare future extension interface
146 * @brief Virtual destructor.
149 DALI_IMPORT_API virtual ~ItemLayout();
152 * @brief Set the orientation of the layout.
155 * @param[in] orientation The orientation of the layout.
157 DALI_IMPORT_API void SetOrientation(ControlOrientation::Type orientation);
160 * @brief Query the orientation of the layout.
163 * @return the orientation of the layout.
165 DALI_IMPORT_API ControlOrientation::Type GetOrientation() const;
168 * @brief Retrieve the target size of an item in the layout.
170 * This will return the default size for the layout unless overridden by calling SetItemSize().
173 * @param[in] itemId The ID of an item in the layout.
174 * @param[in] layoutSize The layout size
175 * @param[out] itemSize The target size of an item.
176 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
177 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
179 DALI_IMPORT_API void GetItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const;
182 * @brief Overrides the default size for the layout.
185 * @param[in] itemSize The size of each item.
187 DALI_IMPORT_API void SetItemSize( const Vector3& itemSize );
190 * @brief Query the minimum valid layout position; this is a negative value.
192 * When scrolling, the first item will move within the range 0 to GetMinimumLayoutPosition().
194 * @param[in] numberOfItems The current number of items in the layout.
195 * @param[in] layoutSize The size of the layout area.
196 * @return The minimum layout position.
198 virtual float GetMinimumLayoutPosition(unsigned int numberOfItems, Vector3 layoutSize) const = 0;
201 * @brief Query the closest anchor position for the given layout position.
203 * This anchor position is the position where all the items in the layout are aligned to
204 * their rounded layout positions in integer.
206 * @param[in] layoutPosition The layout position.
207 * @return The closest anchor position for the given layout position.
209 virtual float GetClosestAnchorPosition(float layoutPosition) const = 0;
212 * @brief Query the layout position for the first item in the layout to move to when the layout
213 * needs to scroll to a particular item.
216 * @param[in] itemId The ID of an item in the layout.
217 * @return The layout position for the first item in the layout to move to.
219 virtual float GetItemScrollToPosition(unsigned int itemId) const = 0;
222 * @brief Query the items within a given layout-area.
225 * @param[in] firstItemPosition The layout-position of the first item in the layout.
226 * @param[in] layoutSize The size of the layout area.
227 * @return The ID of the first & last visible item.
229 virtual ItemRange GetItemsWithinArea(float firstItemPosition, Vector3 layoutSize) const = 0;
232 * @brief Get the closest layout position to bring an item onto the screen.
234 * If the item is already fully on the screen this function will
235 * return the current layout position.
237 * This function is used by systems such as KeyboardFocusManager to
238 * bring the next focusable item into view and all layout
239 * implementations should provide their own version of this function
240 * to ensure proper functionality of internal toolkit systems.
243 * @param[in] itemID id of the item to bring within the viewable screen area
244 * @param[in] currentLayoutPosition the current layout position of the item view instance
245 * @param[in] layoutSize the current size of the item view instance
246 * @return The layout position
248 DALI_IMPORT_API virtual float GetClosestOnScreenLayoutPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize);
251 * @brief Query the number of items that should be reserved, for scrolling purposes.
254 * @param[in] layoutSize The size of the layout area.
255 * @return The number of extra items. ItemView will populate itself with actors within the layout-area
256 * (see GetItemsWithinArea), plus this number of additional items on either-side.
258 virtual unsigned int GetReserveItemCount(Vector3 layoutSize) const = 0;
261 * @brief Retrieve the default size of an item in the layout.
264 * @param[in] itemId The ID of an item in the layout.
265 * @param[in] layoutSize The layout size
266 * @param[out] itemSize The target size of an item.
267 * @note layout-position is not provided as a parameter, since applying size constraints is not recommended.
268 * Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.
270 virtual void GetDefaultItemSize( unsigned int itemId, const Vector3& layoutSize, Vector3& itemSize ) const = 0;
273 * @brief Query the scroll direction of the layout.
275 * When an input gesture follows this direction, the layout-position of items will be increased.
276 * If the input gesture points in the opposite direction, then the layout-positions will decrease.
278 * @return The scroll direction in degrees.
280 virtual Degree GetScrollDirection() const = 0;
283 * @brief Query the scroll speed factor of the layout while dragging.
285 * This factor is used by the layout to customise its scroll speed while dragging.
286 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
287 * and the layout position of the actors in ItemView will be moved by this result.
288 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
289 * position of actors will be moved by 1.
290 * Therefore, the bigger the factor is, the faster the scroll speed will be.
293 * @return The scroll speed factor of the layout.
295 virtual float GetScrollSpeedFactor() const = 0;
298 * @brief Query the maximum swipe speed in pixels per second.
300 * Swipe gestures will be clamped when exceeding this speed limit.
302 * @return speed The maximum swipe speed.
304 virtual float GetMaximumSwipeSpeed() const = 0;
307 * @brief Get the duration of the flick animation in second.
309 * This is the time taken to animate each
310 * item to its next layout position (e.g. from 1.0 to 2.0) when a flick animation is triggered
311 * by a swipe gesture.
313 * @return The duration of the flick animation.
315 virtual float GetItemFlickAnimationDuration() const = 0;
318 * @brief Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.
321 * @param[in] itemID The current focused item
322 * @param[in] maxItems The maximum number of items in the list
323 * @param[in] direction The directional key pressed on the keyboard
324 * @param[in] loopEnabled Whether the KeyboardFocusManager is set to wrap around between first and last item
325 * @return The next item ID.
327 DALI_IMPORT_API virtual int GetNextFocusItemID(int itemID, int maxItems, Dali::Toolkit::Control::KeyboardFocus::Direction direction, bool loopEnabled);
330 * @brief Query the flick speed factor of the layout while swipping.
332 * This factor is used by the layout to customise its scroll speed while swiping.
333 * The factor will be multiplied with the scroll distance of how many pixels in actor coordinate,
334 * and the layout position of the actors in ItemView will be moved by this result.
335 * For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout
336 * position of actors will be moved by 1.
337 * Therefore, the bigger the factor is, the faster the flick speed will be.
340 * @return The scroll speed factor of the layout.
342 DALI_IMPORT_API virtual float GetFlickSpeedFactor() const;
345 * @brief Applies constraints defined by the layout to an actor.
347 * @param[in] actor The actor to constrain.
348 * @param[in] itemId The ID of the item represented by the actor.
349 * @param[in] layoutSize The current size of the item view instance.
350 * @param[in] itemViewActor The item view instance which requests the application of constraints.
352 DALI_IMPORT_API virtual void ApplyConstraints( Actor& actor, const int itemId, const Vector3& layoutSize, const Actor& itemViewActor ) = 0;
355 * @brief Gets the position of a given item
358 * @param[in] itemID The id of the item we want to get its position
359 * @param[in] currentLayoutPosition The current layout position of the item view instance
360 * @param[in] layoutSize The current size of the item view instance
361 * @return The item position (x,y,z)
363 DALI_IMPORT_API virtual Vector3 GetItemPosition(int itemID, float currentLayoutPosition, const Vector3& layoutSize) const = 0;
366 * @brief Retrieve the extension for this layout.
369 * @return The extension if available, NULL otherwise
371 virtual Extension* GetExtension()
379 * @brief Create a new ItemLayout; Only derived versions are instantiatable.
382 DALI_IMPORT_API ItemLayout();
387 * @brief Don't allow copy constructor
390 ItemLayout( const ItemLayout& handle );
393 * @brief Don't allow copy operator
396 ItemLayout& operator=( const ItemLayout& handle );
407 } // namespace Toolkit
411 #endif // __DALI_TOOLKIT_ITEM_LAYOUT_H__