5 * Copyright (c) 2020 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/base-handle.h>
26 #include <dali/public-api/signals/dali-signal.h>
31 * @addtogroup dali_core_common
35 namespace Internal DALI_INTERNAL
52 * @brief The Stage is a top-level object used for displaying a tree of Actors.
54 * Stage is a top-level object that represents the entire screen.
55 * It is used for displaying a hierarchy of actors managed by the scene graph structure,
56 * which means an actor inherits a position relative to its parent,
57 * and can be moved in relation to this point.
59 * The stage instance is a singleton object (the only instance of its class during the
60 * lifetime of the program). You can get it using a static function.
62 * To display the contents of an actor, it must be added to a stage.
63 * The following example shows how to connect a new actor to the stage:
65 * Actor actor = Actor::New();
66 * Stage::GetCurrent().Add( actor );
69 * The stage has a 2D size that matches the size of the application window.
70 * The default unit 1 is 1 pixel with the default camera.
72 * Multiple stage/window support is not currently provided.
75 * | %Signal Name | Method |
76 * |-------------------------|--------------------------------------|
77 * | keyEvent | @ref KeyEventSignal() |
78 * | eventProcessingFinished | @ref EventProcessingFinishedSignal() |
79 * | touched | @ref TouchedSignal() |
80 * | wheelEvent | @ref WheelEventSignal() |
81 * | contextLost | @ref ContextLostSignal() |
82 * | contextRegained | @ref ContextRegainedSignal() |
83 * | sceneCreated | @ref SceneCreatedSignal() |
85 class DALI_CORE_API Stage : public BaseHandle
89 typedef Signal< void (const KeyEvent&) > KeyEventSignalType; ///< Key event signal type
90 typedef Signal< void () > EventProcessingFinishedSignalType; ///< Event Processing finished signal type
91 typedef Signal< void (const TouchEvent&) > TouchEventSignalType; ///< Touch signal type
92 typedef Signal< void (const WheelEvent&) > WheelEventSignalType; ///< Wheel signal type
93 typedef Signal< void () > ContextStatusSignal; ///< Context status signal type
94 typedef Signal< void () > SceneCreatedSignalType; ///< Scene created signal type
97 * @brief Allows the creation of an empty stage handle.
99 * To retrieve the current stage, this handle can be set using Stage::GetCurrent().
104 * @brief Gets the current Stage.
106 * @return The current stage or an empty handle if the internal core has not been created or has been already destroyed
108 static Stage GetCurrent();
111 * @brief Queries whether the Stage exists; this should only return false during or after destruction of Dali core.
113 * @return True when it's safe to call Stage::GetCurrent()
115 static bool IsInstalled();
120 * This is non-virtual since derived Handle types must not contain data or virtual methods.
125 * @brief This copy constructor is required for (smart) pointer semantics.
127 * @param[in] handle A reference to the copied handle
129 Stage(const Stage& handle);
132 * @brief This assignment operator is required for (smart) pointer semantics.
134 * @param[in] rhs A reference to the copied handle
135 * @return A reference to this
137 Stage& operator=(const Stage& rhs);
142 * @brief Adds a child Actor to the Stage.
144 * The child will be referenced.
145 * @param[in] actor The child
146 * @pre The actor has been initialized.
147 * @pre The actor does not have a parent.
149 void Add(Actor& actor);
152 * @brief Removes a child Actor from the Stage.
154 * The child will be unreferenced.
155 * @param[in] actor The child
156 * @pre The actor has been added to the stage.
158 void Remove(Actor& actor);
161 * @brief Returns the size of the Stage in pixels as a Vector.
163 * The x component will be the width of the Stage in pixels.
164 * The y component will be the height of the Stage in pixels.
165 * The z component will be the distance between far and near planes.
166 * @return The size of the Stage as a Vector
168 Vector2 GetSize() const;
173 * @brief Retrieves the list of render-tasks.
175 * @return A valid handle to a RenderTaskList
177 RenderTaskList GetRenderTaskList() const;
182 * @brief Queries the number of on-stage layers.
184 * Note that a default layer is always provided (count >= 1).
185 * @return The number of layers
187 uint32_t GetLayerCount() const;
190 * @brief Retrieves the layer at a specified depth.
192 * @param[in] depth The depth
193 * @return The layer found at the given depth
194 * @pre Depth is less than layer count; see GetLayerCount().
196 Layer GetLayer(uint32_t depth) const;
199 * @brief Returns the Stage's Root Layer.
201 * @return The root layer
203 Layer GetRootLayer() const;
208 * @brief Sets the background color of the stage.
210 * @param[in] color The new background color
212 void SetBackgroundColor(Vector4 color);
215 * @brief Retrieves the background color of the stage.
217 * @return The background color
219 Vector4 GetBackgroundColor() const;
222 * @brief Retrieves the DPI of the display device to which the stage is connected.
224 * @return The horizontal and vertical DPI
226 Vector2 GetDpi() const;
229 * @brief Gets the Object registry.
231 * @return The object registry
233 ObjectRegistry GetObjectRegistry() const;
238 * @brief Keep rendering for at least the given amount of time.
240 * By default, Dali will stop rendering when no Actor positions are being set, and when no animations are running etc.
241 * This method is useful to force screen refreshes e.g. when updating a NativeImage.
242 * @param[in] durationSeconds Time to keep rendering, 0 means render at least one more frame
244 void KeepRendering( float durationSeconds );
249 * @brief This signal is emitted when key event is received.
251 * A callback of the following type may be connected:
253 * void YourCallbackName(const KeyEvent& event);
255 * @return The signal to connect to
257 KeyEventSignalType& KeyEventSignal();
260 * @brief This signal is emitted just after the event processing is finished.
262 * @return The signal to connect to
264 EventProcessingFinishedSignalType& EventProcessingFinishedSignal();
267 * @brief This signal is emitted when the screen is touched and when the touch ends
268 * (i.e. the down & up touch events only).
270 * If there are multiple touch points, then this will be emitted when the first touch occurs and
271 * then when the last finger is lifted.
272 * An interrupted event will also be emitted (if it occurs).
273 * A callback of the following type may be connected:
275 * void YourCallbackName( TouchEvent event );
278 * @return The touch signal to connect to
279 * @note Motion events are not emitted.
281 TouchEventSignalType& TouchedSignal();
284 * @brief This signal is emitted when wheel event is received.
286 * A callback of the following type may be connected:
288 * void YourCallbackName(const WheelEvent& event);
290 * @return The signal to connect to
292 WheelEventSignalType& WheelEventSignal();
295 * @brief This signal is emitted when the GL context is lost (Platform specific behaviour).
297 * If the application is responsible for handling context loss, it should listen to
298 * this signal and tear down UI components when received.
299 * @return The context lost signal to connect to
301 ContextStatusSignal& ContextLostSignal();
304 * @brief This signal is emitted when the GL context is regained (Platform specific
307 * If the application is responsible for handling context loss, it should listen to
308 * this signal and rebuild UI components on receipt.
309 * @return The context regained signal to connect to
311 ContextStatusSignal& ContextRegainedSignal();
314 * @brief This signal is emitted after the initial scene is created.
316 * It will be triggered after the
317 * application init signal.
319 * A callback of the following type may be connected:
321 * void YourCallbackName();
323 * @return The signal to connect to
325 SceneCreatedSignalType& SceneCreatedSignal();
327 public: // Not intended for application developers
331 * @brief This constructor is used by Stage::GetCurrent() methods.
333 * @param[in] stage A pointer to a Dali resource
335 explicit DALI_INTERNAL Stage(Internal::Stage* stage);
345 #endif // DALI_STAGE_H