| // Copyright 2017 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_ACCESSIBILITY_SCREEN_READER_H_ |
| #define COBALT_ACCESSIBILITY_SCREEN_READER_H_ |
| |
| #include "base/memory/scoped_ptr.h" |
| #include "base/memory/scoped_vector.h" |
| #include "cobalt/accessibility/tts_engine.h" |
| #include "cobalt/dom/document.h" |
| #include "cobalt/dom/mutation_observer.h" |
| #include "cobalt/dom/mutation_observer_task_manager.h" |
| |
| namespace cobalt { |
| namespace accessibility { |
| // ScreenReader tracks changes in the state of the Document and provides speech |
| // utterances to a TTSEngine. The main use cases covered are when the document's |
| // focused element changes, usually in response to user input, or if there is |
| // an asynchronous change to "live region" that should be communicated to the |
| // user. |
| class ScreenReader : public dom::DocumentObserver { |
| public: |
| ScreenReader(dom::Document* document, TTSEngine* tts_engine, |
| dom::MutationObserverTaskManager* task_manager); |
| |
| void set_enabled(bool enabled); |
| bool enabled() const { return enabled_; } |
| |
| protected: |
| ~ScreenReader(); |
| // dom::DocumentObserver overrides. |
| void OnLoad() OVERRIDE; |
| void OnMutation() OVERRIDE {} |
| void OnFocusChanged() OVERRIDE; |
| |
| private: |
| typedef script::Sequence<scoped_refptr<dom::MutationRecord> > |
| MutationRecordSequence; |
| void FocusChangedCallback(); |
| // MutationObserver callback for tracking live regions. |
| void MutationObserverCallback( |
| const MutationRecordSequence& sequence, |
| const scoped_refptr<dom::MutationObserver>& observer); |
| |
| bool enabled_; |
| dom::Document* document_; |
| TTSEngine* tts_engine_; |
| scoped_refptr<dom::MutationObserver> live_region_observer_; |
| bool focus_changed_; |
| |
| friend class scoped_ptr<ScreenReader>; |
| DISALLOW_COPY_AND_ASSIGN(ScreenReader); |
| }; |
| } // namespace accessibility |
| } // namespace cobalt |
| |
| #endif // COBALT_ACCESSIBILITY_SCREEN_READER_H_ |