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 <dali/public-api/object/ref-object.h>
23 #include <dali/public-api/actors/actor.h>
24 #include <dali/public-api/math/rect.h>
25 #include <dali/public-api/math/vector3.h>
26 #include <dali/public-api/images/frame-buffer-image.h>
31 * @addtogroup dali_core_actors
35 namespace Internal DALI_INTERNAL
41 * @brief Rectangle describing area on screen that a layer can draw to.
44 * @see Dali::Layer::SetClippingBox()
46 typedef Rect<int> ClippingBox;
49 * @brief Layers provide a mechanism for overlaying groups of actors on top of each other.
51 * When added to the stage, a layer can be ordered relative to other
52 * layers. The bottom layer is at depth zero. The stage provides a default
53 * layer for it's children (see Stage::GetRootLayer()).
55 * Layered actors inherit position etc. as normal, but are drawn in an order
56 * determined by the layers. In case of LAYER_3D, the depth buffer is cleared
57 * before each layer is rendered unless depth test is disabled or there's no
58 * need for it based on the layer's contents; actors in lower layers cannot
59 * obscure actors in higher layers.
61 * A layer has either LAYER_2D or LAYER_3D mode. LAYER_2D has better
62 * performance, the depth test is disabled, and a child actor hides its
63 * parent actor. LAYER_3D uses the depth test, thus a close actor hides a
64 * farther one. LAYER_2D is the default mode and recommended for general
65 * cases. See Layer::Behavior and SetBehavior() for more information.
67 * Layer is a type of Actor, thus can have parent or children actors. A
68 * layer influences rendering of its all descendant actors, until another
69 * layer appears in the actor tree and manages its own subtree.
71 * If depth test is disabled, there is no performance overhead from clearing
75 * | %Action Name | %Layer method called |
76 * |-----------------|----------------------|
77 * | raise | @ref Raise() |
78 * | lower | @ref Lower() |
79 * | raiseToTop | @ref RaiseToTop() |
80 * | lowerToBottom | @ref LowerToBottom() |
83 class DALI_CORE_API Layer : public Actor
88 * @brief Enumeration for the instance of properties belonging to the Layer class.
90 * Properties additional to Actor.
96 * @brief Enumeration for the instance of properties belonging to the Layer class.
98 * Properties additional to Actor.
103 CLIPPING_ENABLE = DEFAULT_DERIVED_ACTOR_PROPERTY_START_INDEX, ///< name "clippingEnable", type bool @SINCE_1_0.0
104 CLIPPING_BOX, ///< name "clippingBox", type Rect<int> @SINCE_1_0.0
105 BEHAVIOR, ///< name "behavior", type String @SINCE_1_0.0
110 * @brief Enumeration for the behavior of the layer.
112 * Check each value to see how it affects the layer.
118 * @DEPRECATED_1_1.45, use LAYER_UI instead
119 * @brief UI control rendering mode.
126 * @brief UI control rendering mode (default mode).
128 * This mode is designed for UI controls that can overlap. In this
129 * mode renderer order will be respective to the tree hierarchy of
132 * The rendering order is depth first, so for the following actor tree,
133 * A will be drawn first, then B, D, E, then C, F. This ensures that
134 * overlapping actors are drawn as expected (whereas, with breadth first
135 * traversal, the actors would interleave).
149 * To change the order of sibling actors, use the Actor::Raise and
150 * Actor::Lower APIs. Within an actor, the Renderer depth index dictates
151 * the order the renderers are drawn.
158 * @brief Layer will use depth test.
160 * This mode is designed for a 3 dimensional scene where actors in front
161 * of other actors will obscure them, i.e. the actors are sorted by the
162 * distance from the camera.
164 * When using this mode, a depth test will be used. A depth clear will
165 * happen for each layer, which means actors in a layer "above" other
166 * layers will be rendered in front of actors in those layers regardless
167 * of their Z positions (see Layer::Raise() and Layer::Lower()).
169 * Opaque renderers are drawn first and write to the depth buffer. Then
170 * transparent renderers are drawn with depth test enabled but depth
171 * write switched off. Transparent renderers are drawn based on their
172 * distance from the camera. A renderer's DEPTH_INDEX property is used to
173 * offset the distance to the camera when ordering transparent renderers.
175 * This is useful if you want to define the draw order of two or more
176 * transparent renderers that are equal distance from the camera. Unlike
177 * LAYER_UI, parent-child relationship does not affect rendering order at
187 * @DEPRECATED_1_2.26. Not intended for application use.
189 * @brief Enumeration for TREE_DEPTH_MULTIPLIER is used by the rendering sorting algorithm to decide which actors to render first.
192 enum TreeDepthMultiplier
194 TREE_DEPTH_MULTIPLIER = 10000,
198 * @brief The sort function type.
201 * @param[in] position This is the actor translation from camera
203 typedef float (*SortFunctionType)( const Vector3& position );
206 * @brief Creates an empty Layer handle.
208 * This can be initialized with Layer::New(...).
214 * @brief Creates a Layer object.
217 * @return A handle to a newly allocated Layer
222 * @brief Downcasts a handle to Layer handle.
224 * If handle points to a Layer, the downcast produces valid handle.
225 * If not, the returned handle is left uninitialized.
227 * @param[in] handle Handle to an object
228 * @return Handle to a Layer or an uninitialized handle
230 static Layer DownCast( BaseHandle handle );
235 * This is non-virtual since derived Handle types must not contain data or virtual methods.
241 * @brief Copy constructor.
244 * @param[in] copy The actor to copy
246 Layer(const Layer& copy);
249 * @brief Assignment operator.
252 * @param[in] rhs The actor to copy
253 * @return A reference to this
255 Layer& operator=(const Layer& rhs);
258 * @brief Queries the depth of the layer.
260 * 0 is the bottom most layer, higher number is on top.
262 * @return The current depth of the layer
263 * @pre Layer is on the stage.
264 * If layer is not added to the stage, returns 0.
266 unsigned int GetDepth() const;
269 * @brief Increments the depth of the layer.
272 * @pre Layer is on the stage.
277 * @brief Decrements the depth of the layer.
280 * @pre Layer is on the stage.
285 * @brief Ensures the layers depth is greater than the target layer.
287 * If the layer already is above the target layer, its depth is not changed.
288 * If the layer was below target, its new depth will be immediately above target.
290 * @param target Layer to get above of
291 * @pre Layer is on the stage.
292 * @pre Target layer is on the stage.
293 * @note All layers between this layer and target get new depth values.
295 void RaiseAbove( Layer target );
298 * @brief Ensures the layers depth is less than the target layer.
300 * If the layer already is below the target layer, its depth is not changed.
301 * If the layer was above target, its new depth will be immediately below target.
303 * @param target Layer to get below of
304 * @pre Layer is on the stage.
305 * @pre Target layer is on the stage.
306 * @note All layers between this layer and target get new depth values.
308 void LowerBelow( Layer target );
311 * @brief Raises the layer to the top.
313 * @pre Layer is on the stage.
318 * @brief Lowers the layer to the bottom.
320 * @pre layer is on the stage.
322 void LowerToBottom();
325 * @brief Moves the layer directly above the given layer.
327 * After the call, this layers depth will be immediately above target.
329 * @param target Layer to get on top of
330 * @pre Layer is on the stage.
331 * @pre Target layer is on the stage.
332 * @note All layers between this layer and target get new depth values.
334 void MoveAbove( Layer target );
337 * @brief Moves the layer directly below the given layer.
339 * After the call, this layers depth will be immediately below target.
341 * @param target Layer to get below of
342 * @pre Layer is on the stage.
343 * @pre Target layer is on the stage.
344 * @note All layers between this layer and target get new depth values.
346 void MoveBelow( Layer target );
349 * @brief Sets the behavior of the layer.
352 * @param[in] behavior The desired behavior
354 void SetBehavior( Behavior behavior );
357 * @brief Gets the behavior of the layer.
360 * @return The behavior of the layer
362 Behavior GetBehavior() const;
365 * @brief Sets whether clipping is enabled for a layer.
367 * Clipping is initially disabled; see also SetClippingBox().
369 * @param[in] enabled True if clipping is enabled
371 * @note When clipping is enabled, the default clipping box is empty (0,0,0,0), which means everything is clipped.
373 void SetClipping(bool enabled);
376 * @brief Queries whether clipping is enabled for a layer.
378 * @return True if clipping is enabled
380 bool IsClipping() const;
383 * @brief Sets the clipping box of a layer, in window coordinates.
385 * The contents of the layer will not be visible outside this box, when clipping is
386 * enabled. The default clipping box is empty (0,0,0,0) which means everything is clipped.
387 * You can only do rectangular clipping using this API in window coordinates.
389 * @param[in] x The X-coordinate of the top-left corner of the box
390 * @param[in] y The Y-coordinate of the top-left corner of the box
391 * @param[in] width The width of the box
392 * @param[in] height The height of the box
394 void SetClippingBox(int x, int y, int width, int height);
397 * @brief Sets the clipping box of a layer in window coordinates.
399 * The contents of the layer will not be visible outside this box when clipping is
400 * enabled. The default clipping box is empty (0,0,0,0).
402 * @param[in] box The clipping box
404 void SetClippingBox(ClippingBox box);
407 * @brief Retrieves the clipping box of a layer in window coordinates.
410 * @return The clipping box
412 ClippingBox GetClippingBox() const;
417 * @brief Whether to disable the depth test.
419 * 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.
420 * However, it's possible to disable the depth test by calling this method.
423 * @param[in] disable \e True disables depth test. \e false sets the default behavior
425 void SetDepthTestDisabled( bool disable );
428 * @brief Retrieves whether depth test is disabled.
431 * @return \e True if depth test is disabled
433 bool IsDepthTestDisabled() const;
438 * @brief This allows the user to specify the sort function that the layer should use.
440 * The sort function is used to determine the order in which the actors are drawn
441 * and input is processed on the actors in the layer.
443 * A function of the following type should be used:
445 * float YourSortFunction(const Vector3& position);
449 * @param[in] function The sort function pointer
450 * @note If the sort function returns a low number, the actor with the data will be
451 * drawn in front of an actor whose data yields a high value from the sort function.
453 * @note All child layers use the same sort function. If a child layer is added to this
454 * layer, then the sort function used by the child layer will also be the same.
457 void SetSortFunction( SortFunctionType function );
460 * @brief This allows the user to specify whether this layer should consume touch (including gestures).
462 * If set, any layers behind this layer will not be hit-test.
465 * @param[in] consume Whether the layer should consume touch (including gestures)
467 void SetTouchConsumed( bool consume );
470 * @brief Retrieves whether the layer consumes touch (including gestures).
473 * @return @c True if consuming touch, @c false otherwise
475 bool IsTouchConsumed() const;
478 * @brief This allows the user to specify whether this layer should consume hover.
480 * If set, any layers behind this layer will not be hit-test.
483 * @param[in] consume Whether the layer should consume hover
485 void SetHoverConsumed( bool consume );
488 * @brief Retrieves whether the layer consumes hover.
491 * @return @c True if consuming hover, @c false otherwise
493 bool IsHoverConsumed() const;
495 public: // Not intended for application developers
499 * @brief This constructor is used by Layer::New() methods.
502 * @param[in] Layer A pointer to a newly allocated Dali resource
504 explicit DALI_INTERNAL Layer(Internal::Layer* Layer);
513 #endif // DALI_LAYER_H