5 * Copyright (c) 2018 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 <cstdint> // uint32_t
25 #include <dali/public-api/object/ref-object.h>
26 #include <dali/public-api/actors/actor.h>
27 #include <dali/public-api/math/rect.h>
28 #include <dali/public-api/math/vector3.h>
29 #include <dali/public-api/images/frame-buffer-image.h>
34 * @addtogroup dali_core_actors
38 namespace Internal DALI_INTERNAL
44 * @brief Rectangle describing area on screen that a layer can draw to.
47 * @see Dali::Layer::SetClippingBox()
49 typedef Rect<int32_t> ClippingBox;
52 * @brief Layers provide a mechanism for overlaying groups of actors on top of each other.
54 * When added to the stage, a layer can be ordered relative to other
55 * layers. The bottom layer is at depth zero. The stage provides a default
56 * layer for it's children (see Stage::GetRootLayer()).
58 * Layered actors inherit position etc. as normal, but are drawn in an order
59 * determined by the layers. In case of LAYER_3D, the depth buffer is cleared
60 * before each layer is rendered unless depth test is disabled or there's no
61 * need for it based on the layer's contents; actors in lower layers cannot
62 * obscure actors in higher layers.
64 * A layer has either LAYER_UI or LAYER_3D mode. LAYER_UI has better
65 * performance, the depth test is disabled, and a child actor hides its
66 * parent actor. LAYER_3D uses the depth test, thus a close actor hides a
67 * farther one. LAYER_UI is the default mode and recommended for general
68 * cases. See Layer::Behavior and SetBehavior() for more information.
70 * Layer is a type of Actor, thus can have parent or children actors. A
71 * layer influences rendering of its all descendant actors, until another
72 * layer appears in the actor tree and manages its own subtree.
74 * If depth test is disabled, there is no performance overhead from clearing
78 * | %Action Name | %Layer method called |
79 * |-----------------|----------------------|
80 * | raise | @ref Raise() |
81 * | lower | @ref Lower() |
82 * | raiseToTop | @ref RaiseToTop() |
83 * | lowerToBottom | @ref LowerToBottom() |
86 class DALI_CORE_API Layer : public Actor
91 * @brief Enumeration for the instance of properties belonging to the Layer class.
93 * Properties additional to Actor.
99 * @brief Enumeration for the instance of properties belonging to the Layer class.
101 * Properties additional to Actor.
106 CLIPPING_ENABLE = DEFAULT_DERIVED_ACTOR_PROPERTY_START_INDEX, ///< name "clippingEnable", type bool @SINCE_1_0.0
107 CLIPPING_BOX, ///< name "clippingBox", type Rect<int32_t> @SINCE_1_0.0
108 BEHAVIOR, ///< name "behavior", type String @SINCE_1_0.0
113 * @brief Enumeration for the behavior of the layer.
115 * Check each value to see how it affects the layer.
121 * @brief UI control rendering mode (default mode).
123 * This mode is designed for UI controls that can overlap. In this
124 * mode renderer order will be respective to the tree hierarchy of
127 * The rendering order is depth first, so for the following actor tree,
128 * A will be drawn first, then B, D, E, then C, F. This ensures that
129 * overlapping actors are drawn as expected (whereas, with breadth first
130 * traversal, the actors would interleave).
144 * To change the order of sibling actors, use the Actor::Raise and
145 * Actor::Lower APIs. Within an actor, the Renderer depth index dictates
146 * the order the renderers are drawn.
153 * @brief Layer will use depth test.
155 * This mode is designed for a 3 dimensional scene where actors in front
156 * of other actors will obscure them, i.e. the actors are sorted by the
157 * distance from the camera.
159 * When using this mode, a depth test will be used. A depth clear will
160 * happen for each layer, which means actors in a layer "above" other
161 * layers will be rendered in front of actors in those layers regardless
162 * of their Z positions (see Layer::Raise() and Layer::Lower()).
164 * Opaque renderers are drawn first and write to the depth buffer. Then
165 * transparent renderers are drawn with depth test enabled but depth
166 * write switched off. Transparent renderers are drawn based on their
167 * distance from the camera. A renderer's DEPTH_INDEX property is used to
168 * offset the distance to the camera when ordering transparent renderers.
170 * This is useful if you want to define the draw order of two or more
171 * transparent renderers that are equal distance from the camera. Unlike
172 * LAYER_UI, parent-child relationship does not affect rendering order at
182 * @DEPRECATED_1_2.26. Not intended for application use.
184 * @brief Enumeration for TREE_DEPTH_MULTIPLIER is used by the rendering sorting algorithm to decide which actors to render first.
187 enum TreeDepthMultiplier
189 TREE_DEPTH_MULTIPLIER = 10000,
193 * @brief The sort function type.
196 * @param[in] position This is the actor translation from camera
198 typedef float (*SortFunctionType)( const Vector3& position );
201 * @brief Creates an empty Layer handle.
203 * This can be initialized with Layer::New(...).
209 * @brief Creates a Layer object.
212 * @return A handle to a newly allocated Layer
217 * @brief Downcasts a handle to Layer handle.
219 * If handle points to a Layer, the downcast produces valid handle.
220 * If not, the returned handle is left uninitialized.
222 * @param[in] handle Handle to an object
223 * @return Handle to a Layer or an uninitialized handle
225 static Layer DownCast( BaseHandle handle );
230 * This is non-virtual since derived Handle types must not contain data or virtual methods.
236 * @brief Copy constructor.
239 * @param[in] copy The actor to copy
241 Layer(const Layer& copy);
244 * @brief Assignment operator.
247 * @param[in] rhs The actor to copy
248 * @return A reference to this
250 Layer& operator=(const Layer& rhs);
253 * @brief Queries the depth of the layer.
255 * 0 is the bottom most layer, higher number is on top.
257 * @return The current depth of the layer
258 * @pre Layer is on the stage.
259 * If layer is not added to the stage, returns 0.
261 uint32_t GetDepth() const;
264 * @brief Increments the depth of the layer.
267 * @pre Layer is on the stage.
272 * @brief Decrements the depth of the layer.
275 * @pre Layer is on the stage.
280 * @brief Ensures the layers depth is greater than the target layer.
282 * If the layer already is above the target layer, its depth is not changed.
283 * If the layer was below target, its new depth will be immediately above target.
285 * @param target Layer to get above of
286 * @pre Layer is on the stage.
287 * @pre Target layer is on the stage.
288 * @note All layers between this layer and target get new depth values.
290 void RaiseAbove( Layer target );
293 * @brief Ensures the layers depth is less than the target layer.
295 * If the layer already is below the target layer, its depth is not changed.
296 * If the layer was above target, its new depth will be immediately below target.
298 * @param target Layer to get below of
299 * @pre Layer is on the stage.
300 * @pre Target layer is on the stage.
301 * @note All layers between this layer and target get new depth values.
303 void LowerBelow( Layer target );
306 * @brief Raises the layer to the top.
308 * @pre Layer is on the stage.
313 * @brief Lowers the layer to the bottom.
315 * @pre layer is on the stage.
317 void LowerToBottom();
320 * @brief Moves the layer directly above the given layer.
322 * After the call, this layers depth will be immediately above target.
324 * @param target Layer to get on top of
325 * @pre Layer is on the stage.
326 * @pre Target layer is on the stage.
327 * @note All layers between this layer and target get new depth values.
329 void MoveAbove( Layer target );
332 * @brief Moves the layer directly below the given layer.
334 * After the call, this layers depth will be immediately below target.
336 * @param target Layer to get below of
337 * @pre Layer is on the stage.
338 * @pre Target layer is on the stage.
339 * @note All layers between this layer and target get new depth values.
341 void MoveBelow( Layer target );
344 * @brief Sets the behavior of the layer.
347 * @param[in] behavior The desired behavior
349 void SetBehavior( Behavior behavior );
352 * @brief Gets the behavior of the layer.
355 * @return The behavior of the layer
357 Behavior GetBehavior() const;
360 * @brief Sets whether clipping is enabled for a layer.
362 * Clipping is initially disabled; see also SetClippingBox().
364 * @param[in] enabled True if clipping is enabled
366 * @note When clipping is enabled, the default clipping box is empty (0,0,0,0), which means everything is clipped.
368 void SetClipping(bool enabled);
371 * @brief Queries whether clipping is enabled for a layer.
373 * @return True if clipping is enabled
375 bool IsClipping() const;
378 * @brief Sets the clipping box of a layer, in window coordinates.
380 * The contents of the layer will not be visible outside this box, when clipping is
381 * enabled. The default clipping box is empty (0,0,0,0) which means everything is clipped.
382 * You can only do rectangular clipping using this API in window coordinates.
384 * @param[in] x The X-coordinate of the top-left corner of the box
385 * @param[in] y The Y-coordinate of the top-left corner of the box
386 * @param[in] width The width of the box
387 * @param[in] height The height of the box
389 void SetClippingBox(int32_t x, int32_t y, int32_t width, int32_t height);
392 * @brief Sets the clipping box of a layer in window coordinates.
394 * The contents of the layer will not be visible outside this box when clipping is
395 * enabled. The default clipping box is empty (0,0,0,0).
397 * @param[in] box The clipping box
399 void SetClippingBox(ClippingBox box);
402 * @brief Retrieves the clipping box of a layer in window coordinates.
405 * @return The clipping box
407 ClippingBox GetClippingBox() const;
412 * @brief Whether to disable the depth test.
414 * By default a layer enables depth test if there is more than one opaque actor or if there is one opaque actor and one, or more, transparent actors in LAYER_3D mode.
415 * However, it's possible to disable the depth test by calling this method.
418 * @param[in] disable \e True disables depth test. \e false sets the default behavior
420 void SetDepthTestDisabled( bool disable );
423 * @brief Retrieves whether depth test is disabled.
426 * @return \e True if depth test is disabled
428 bool IsDepthTestDisabled() const;
433 * @brief This allows the user to specify the sort function that the layer should use.
435 * The sort function is used to determine the order in which the actors are drawn
436 * and input is processed on the actors in the layer.
438 * A function of the following type should be used:
440 * float YourSortFunction(const Vector3& position);
444 * @param[in] function The sort function pointer
445 * @note If the sort function returns a low number, the actor with the data will be
446 * drawn in front of an actor whose data yields a high value from the sort function.
448 * @note All child layers use the same sort function. If a child layer is added to this
449 * layer, then the sort function used by the child layer will also be the same.
452 void SetSortFunction( SortFunctionType function );
455 * @brief This allows the user to specify whether this layer should consume touch (including gestures).
457 * If set, any layers behind this layer will not be hit-test.
460 * @param[in] consume Whether the layer should consume touch (including gestures)
462 void SetTouchConsumed( bool consume );
465 * @brief Retrieves whether the layer consumes touch (including gestures).
468 * @return @c True if consuming touch, @c false otherwise
470 bool IsTouchConsumed() const;
473 * @brief This allows the user to specify whether this layer should consume hover.
475 * If set, any layers behind this layer will not be hit-test.
478 * @param[in] consume Whether the layer should consume hover
480 void SetHoverConsumed( bool consume );
483 * @brief Retrieves whether the layer consumes hover.
486 * @return @c True if consuming hover, @c false otherwise
488 bool IsHoverConsumed() const;
490 public: // Not intended for application developers
494 * @brief This constructor is used by Layer::New() methods.
497 * @param[in] Layer A pointer to a newly allocated Dali resource
499 explicit DALI_INTERNAL Layer(Internal::Layer* Layer);
508 #endif // DALI_LAYER_H