1 #ifndef DALI_ADAPTOR_ACCESSIBILITY_BRIDGE_H
2 #define DALI_ADAPTOR_ACCESSIBILITY_BRIDGE_H
5 * Copyright (c) 2024 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/actors/actor.h>
23 #include <dali/public-api/events/key-event.h>
24 #include <dali/public-api/math/rect.h>
29 #include <unordered_set>
32 #include <dali/devel-api/adaptor-framework/accessibility.h>
33 #include <dali/public-api/adaptor-framework/window.h>
37 namespace Accessibility
40 class ProxyAccessible;
43 * @brief Base class for different accessibility bridges.
45 * Bridge is resposible for initializing and managing connection on accessibility bus.
46 * Accessibility clients will not get any information about UI without initialized and upraised bridge.
47 * Concrete implementation depends on the accessibility technology available on the platform.
49 * @note This class is singleton.
51 struct DALI_ADAPTOR_API Bridge
53 enum class ForceUpResult
63 virtual ~Bridge() = default;
66 * @brief Gets bus name which bridge is initialized on.
68 * @return The bus name
70 virtual const std::string& GetBusName() const = 0;
73 * @brief Registers top level window.
75 * Hierarchy of objects visible for accessibility clients is based on tree-like
76 * structure created from Actors objects. This method allows to connect chosen
77 * object as direct ancestor of application and therefore make it visible for
78 * accessibility clients.
80 * @param[in] object The accessible object
82 virtual void AddTopLevelWindow(Accessible* object) = 0;
85 * @brief Removes top level window.
87 * Hierarchy of objects visible for accessibility clients is based on tree-like
88 * structure created from Actors objects. This method removes previously added
89 * window from visible accessibility objects.
91 * @param[in] object The accessible object
93 virtual void RemoveTopLevelWindow(Accessible* object) = 0;
96 * @brief Adds object on the top of the stack of "default label" sourcing objects.
98 * @see GetDefaultLabel
100 * @param[in] object The accessible object
102 virtual void RegisterDefaultLabel(Accessible* object) = 0;
105 * @brief Removes object from the stack of "default label" sourcing objects.
107 * @see GetDefaultLabel
109 * @param[in] object The accessible object
111 virtual void UnregisterDefaultLabel(Accessible* object) = 0;
114 * @brief Gets the top-most object from the stack of "default label" sourcing objects.
116 * The "default label" is a reading material (text) derived from an accesibility object
117 * that could be read by screen-reader immediately after the navigation context has changed
118 * (window activates, popup shows up, tab changes) and before first UI element is highlighted.
120 * @param[in] root The root of the navigation context for which to retrieve the default label.
122 * @return The handler to accessibility object
123 * @note This is a Tizen only feature not present in upstream ATSPI.
124 * Feature can be enabled/disabled for particular context root object
125 * by setting value of its accessibility attribute "default_label".
126 * Following strings are valid values for "default_label" attribute: "enabled", "disabled".
127 * Any other value will be interpreted as "enabled".
129 virtual Accessible* GetDefaultLabel(Accessible* root) const = 0;
132 * @brief Sets name of current application which will be visible on accessibility bus.
134 * @param[in] name The application name
136 virtual void SetApplicationName(std::string name) = 0;
139 * @brief Sets the name of the GUI toolkit that AT-SPI clients can query.
141 * The default name is "dali".
143 * @param toolkitName The toolkit name
145 virtual void SetToolkitName(std::string_view toolkitName) = 0;
148 * @brief Gets object being root of accessibility tree.
150 * @return handler to accessibility object
152 virtual Accessible* GetApplication() const = 0;
155 * @brief Finds an object in accessibility tree.
157 * @param[in] path The path to object
159 * @return The handler to accessibility object
161 virtual Accessible* FindByPath(const std::string& path) const = 0;
164 * @brief Notifies accessibility dbus that window has just been created.
166 * @param[in] window The window to be created
168 virtual void WindowCreated(Window window) = 0;
171 * @brief Notifies accessibility dbus that window has just been shown.
173 * @param[in] window The window to be shown
175 virtual void WindowShown(Window window) = 0;
178 * @brief Notifies accessibility dbus that window has just been hidden.
180 * @param[in] window The window to be hidden
182 virtual void WindowHidden(Window window) = 0;
185 * @brief Notifies accessibility dbus that window has just been focused.
187 * @param[in] window The window to be focused
189 virtual void WindowFocused(Window window) = 0;
192 * @brief Notifies accessibility dbus that window has just been out of focus.
194 * @param[in] window The window to be out of focus
196 virtual void WindowUnfocused(Window window) = 0;
199 * @brief Notifies accessibility dbus that window has just been minimized.
201 * @param[in] window The window to be minimized
203 virtual void WindowMinimized(Window window) = 0;
206 * @brief Notifies accessibility dbus that window has just been restored.
208 * @param[in] window The window to be restored
209 * @param[in] detail Restored window state
211 virtual void WindowRestored(Window window, WindowRestoreType detail) = 0;
214 * @brief Notifies accessibility dbus that window has just been maximized.
216 * @param[in] window The window to be maximized
218 virtual void WindowMaximized(Window window) = 0;
221 * @brief Initializes accessibility bus.
223 virtual void Initialize() = 0;
226 * @brief Terminates accessibility bus.
228 virtual void Terminate() = 0;
231 * @brief This method is called, when bridge is being activated.
233 virtual ForceUpResult ForceUp()
237 return ForceUpResult::ALREADY_UP;
239 mData = std::make_shared<Data>();
240 mData->mBridge = this;
241 return ForceUpResult::JUST_STARTED;
245 * @brief This method is called, when bridge is being deactivated.
247 virtual void ForceDown() = 0;
250 * @brief Checks if bridge is activated or not.
251 * @return True if brige is activated.
259 * @brief Emits cursor-moved event on at-spi bus.
261 * @param[in] obj The accessible object
262 * @param[in] cursorPosition The new cursor position
264 virtual void EmitCursorMoved(Accessible* obj, unsigned int cursorPosition) = 0;
267 * @brief Emits active-descendant-changed event on at-spi bus.
269 * @param[in] obj The accessible object
270 * @param[in] child The child of the object
272 virtual void EmitActiveDescendantChanged(Accessible* obj, Accessible* child) = 0;
275 * @brief Emits text-changed event on at-spi bus.
277 * @param[in] obj The accessible object
278 * @param[in] state The changed state for text, such as Inserted or Deleted
279 * @param[in] position The cursor position
280 * @param[in] length The text length
281 * @param[in] content The changed text
283 virtual void EmitTextChanged(Accessible* obj, TextChangedState state, unsigned int position, unsigned int length, const std::string& content) = 0;
286 * @brief Emits MoveOuted event on at-spi bus.
288 * @param[in] obj Accessible object
289 * @param[in] type Direction type when an Accessible object moves out of screen
291 virtual void EmitMovedOutOfScreen(Accessible* obj, ScreenRelativeMoveType type) = 0;
294 * @brief Emits "org.a11y.atspi.Socket.Available" event on AT-SPI bus.
296 * @param obj Accessible object
298 virtual void EmitSocketAvailable(Accessible* obj) = 0;
301 * @brief Emits ScrollStarted event on at-spi bus.
303 * @param obj Accessible Object
305 virtual void EmitScrollStarted(Accessible *obj) = 0;
308 * @brief Emits ScrollFinished event on at-spi bus.
310 * @param obj Accessible Object
312 virtual void EmitScrollFinished(Accessible *obj) = 0;
315 * @brief Emits state-changed event on at-spi bus.
317 * @param[in] obj The accessible object
318 * @param[in] state The accessibility state (SHOWING, HIGHLIGHTED, etc)
319 * @param[in] newValue Whether the state value is changed to new value or not.
320 * @param[in] reserved Reserved. (Currently, this argument is not implemented in dali)
322 virtual void EmitStateChanged(Accessible* obj, State state, int newValue, int reserved = 0) = 0;
325 * @brief Emits window event on at-spi bus.
327 * @param[in] obj The accessible object
328 * @param[in] event The enumerated window event
329 * @param[in] detail The additional parameter which interpretation depends on chosen event
331 virtual void Emit(Accessible* obj, WindowEvent event, unsigned int detail = 0) = 0;
334 * @brief Emits property-changed event on at-spi bus.
336 * @param[in] obj The accessible object
337 * @param[in] event Property changed event
339 virtual void Emit(Accessible* obj, ObjectPropertyChangeEvent event) = 0;
342 * @brief Emits bounds-changed event on at-spi bus.
344 * @param[in] obj The accessible object
345 * @param[in] rect The rectangle for changed bounds
347 virtual void EmitBoundsChanged(Accessible* obj, Rect<> rect) = 0;
350 * @brief Emits org.a11y.atspi.Event.Window.PostRender on the AT-SPI bus.
352 * @param[in] obj The Accessible sender object
354 * The sender of this event is expected to be an Accessible object that
355 * represents a top-level window.
357 * The actual number of events emitted during a given time interval may be smaller
358 * than the number of calls to this method, but at least one is guaranteed.
360 virtual void EmitPostRender(Accessible *obj) = 0;
363 * @brief Emits key event on at-spi bus.
365 * Screen-reader might receive this event and reply, that given keycode is consumed. In that case
366 * further processing of the keycode should be ignored.
368 * @param[in] keyEvent The key event
369 * @param[in] callback Notification if the event was consumed
370 * @return true if the event was emitted
372 virtual bool EmitKeyEvent(Dali::KeyEvent keyEvent, std::function<void(Dali::KeyEvent, bool)> callback) = 0;
375 * @brief Reads given text by screen reader
377 * @param[in] text The text to read
378 * @param[in] discardable If TRUE, reading can be discarded by subsequent reading requests,
379 * if FALSE the reading must finish before next reading request can be started
380 * @param[in] callback the callback function that is called on reading signals emitted
381 * during processing of this reading request.
382 * Callback can be one of the following signals:
383 * ReadingCancelled, ReadingStopped, ReadingSkipped
385 virtual void Say(const std::string& text, bool discardable, std::function<void(std::string)> callback) = 0;
388 * @brief Force accessibility client to pause.
390 virtual void Pause() = 0;
393 * @brief Force accessibility client to resume.
395 virtual void Resume() = 0;
398 * @brief Cancels anything screen-reader is reading / has queued to read
400 * @param[in] alsoNonDiscardable whether to cancel non-discardable readings as well
402 virtual void StopReading(bool alsoNonDiscardable) = 0;
405 * @brief Suppresses reading of screen-reader
407 * @param[in] suppress whether to suppress reading of screen-reader
409 virtual void SuppressScreenReader(bool suppress) = 0;
412 * @brief Gets screen reader status.
414 * @return True if screen reader is enabled
416 virtual bool GetScreenReaderEnabled() = 0;
419 * @brief Gets ATSPI status.
421 * @return True if ATSPI is enabled
423 virtual bool IsEnabled() = 0;
426 * @brief Calls socket.Embed(plug) via D-Bus.
428 * @param[in] plug The plug
429 * @param[in] socket The socket
431 * @return Address returned by the D-Bus call.
433 * @note Remote object pointed to by 'socket' must implement 'org.a11y.atspi.Socket'.
434 * @see UnembedSocket()
436 virtual Address EmbedSocket(const Address& plug, const Address& socket) = 0;
439 * @brief Calls socket.Embedded(plug) via D-Bus.
441 * The "Embedded" D-Bus method is an ATK extension.
442 * See 'impl_Embedded' in AT_SPI2_ATK/atk-adaptor/adaptors/socket-adaptor.c for more information.
444 * @param[in] plug The plug
445 * @param[in] socket The socket
447 virtual void EmbedAtkSocket(const Address& plug, const Address& socket) = 0;
450 * @brief Calls socket.Unmbed(plug) via D-Bus.
452 * @param[in] plug The plug
453 * @param[in] socket The socket
455 * @note Remote object pointed to by 'socket' must implement 'org.a11y.atspi.Socket'.
458 virtual void UnembedSocket(const Address& plug, const Address& socket) = 0;
461 * @brief Calls socket.SetOffset(x, y) via D-Bus.
463 * The "SetOffset" D-Bus method is a DALi extension. It can be used to inform a DALi widget about
464 * its position on the screen.
466 * @param[in] socket The socket
467 * @param[in] x Horizontal offset
468 * @param[in] y Vertical offset
470 * @note Remote object pointed to by 'socket' must implement 'org.a11y.atspi.Socket'.
472 * @see SetExtentsOffset()
474 virtual void SetSocketOffset(ProxyAccessible* socket, std::int32_t x, std::int32_t y) = 0;
477 * @brief Sets the global extents offset.
479 * This offset will be added during serialization of GetExtents() return value to D-Bus.
480 * Local calls to GetExtents() are unaffected.
482 * @param[in] x Horizontal offset
483 * @param[in] y Vertical offset
485 * @see SetSocketOffset()
486 * @see Dali::Accessibility::Component::GetExtents()
488 virtual void SetExtentsOffset(std::int32_t x, std::int32_t y) = 0;
491 * @brief Sets the preferred bus name.
493 * If the Bridge is enabled, it will immediately release the previous name and request the new one.
495 * Otherwise, the Bridge will request this name on AT-SPI activation (and release it on deactivation).
496 * It is up to the caller to determine whether a given name will be available in the system.
498 * @param preferredBusName The preferred bus name
500 virtual void SetPreferredBusName(std::string_view preferredBusName) = 0;
503 * @brief Returns instance of bridge singleton object.
505 * @return The current bridge object
507 static std::shared_ptr<Bridge> GetCurrentBridge();
510 * @brief Blocks auto-initialization of AT-SPI bridge
512 * Use this only if your application starts before DBus does, and call it early in main()
513 * (before GetCurrentBridge() is called by anyone). GetCurrentBridge() will then return an
514 * instance of DummyBridge.
516 * When DBus is ready, call EnableAutoInit(). Please note that GetCurrentBridge() may still
517 * return an instance of DummyBridge if AT-SPI was disabled at compile time or using an
518 * environment variable, or if creating the real bridge failed.
520 * @see Dali::Accessibility::DummyBridge
521 * @see Dali::Accessibility::Bridge::EnableAutoInit
523 static void DisableAutoInit();
526 * @brief Re-enables auto-initialization of AT-SPI bridge
528 * Normal applications do not have to call this function. GetCurrentBridge() tries to
529 * initialize the AT-SPI bridge when it is called for the first time.
531 * @see Dali::Accessibility::Bridge::DisableAutoInit
532 * @see Dali::Accessibility::Bridge::AddTopLevelWindow
533 * @see Dali::Accessibility::Bridge::SetApplicationName
535 static void EnableAutoInit();
538 * @brief Encodes a widget ID as a usable bus name.
540 * @param widgetInstanceId The instance ID of a widget
541 * @return std::string Encoded bus name
543 * @see SetPreferredBusName
545 static std::string MakeBusNameForWidget(std::string_view widgetInstanceId);
547 static Signal<void()>& EnabledSignal()
549 return mEnabledSignal;
552 static Signal<void()>& DisabledSignal()
554 return mDisabledSignal;
557 static Signal<void()>& ScreenReaderEnabledSignal()
559 return mScreenReaderEnabledSignal;
562 static Signal<void()>& ScreenReaderDisabledSignal()
564 return mScreenReaderDisabledSignal;
570 std::unordered_set<const Accessible*> mKnownObjects;
571 std::string mBusName;
572 Bridge* mBridge = nullptr;
573 Actor mHighlightActor;
574 Actor mCurrentlyHighlightedActor;
575 std::pair<std::int32_t, std::int32_t> mExtentsOffset{0, 0};
577 std::shared_ptr<Data> mData;
578 friend class Accessible;
580 enum class AutoInitState
586 inline static AutoInitState mAutoInitState = AutoInitState::ENABLED;
588 inline static Signal<void()> mEnabledSignal;
589 inline static Signal<void()> mDisabledSignal;
590 inline static Signal<void()> mScreenReaderEnabledSignal;
591 inline static Signal<void()> mScreenReaderDisabledSignal;
594 * @brief Registers accessible object to be known in bridge object.
596 * Bridge must known about all currently alive accessible objects, as some requst
597 * might come and object will be identified by number id (it's memory address).
598 * To avoid memory corruption number id is checked against set of known objects.
600 * @param[in] object The accessible object
602 void RegisterOnBridge(const Accessible* object);
605 * @brief Tells bridge, that given object is considered root (doesn't have any parents).
607 * All root objects will have the same parent - application object. Application object
608 * is controlled by bridge and private.
610 * @param[in] owner The accessible object
612 void SetIsOnRootLevel(Accessible* owner);
616 * @brief Checks if ATSPI is activated or not.
617 * @return True if ATSPI is activated.
621 if(Bridge::GetCurrentBridge() == nullptr)
626 if(Bridge::GetCurrentBridge()->IsEnabled() == false)
631 return Bridge::GetCurrentBridge()->IsUp();
634 } // namespace Accessibility
637 #endif // DALI_ADAPTOR_ACCESSIBILITY_BRIDGE_H