Add high contrast accessibility support for TV (#237)

Author: zhouleonlei

shell/platform/tizen/BUILD.gn

@@ -100,6 +100,7 @@ template("embedder") {
     public = _public_headers
 
     sources = [
+      "accessibility_settings.cc",
       "channels/app_control.cc",
       "channels/app_control_channel.cc",
       "channels/feedback_manager.cc",

shell/platform/tizen/accessibility_settings.cc

@@ -0,0 +1,69 @@
+// Copyright 2022 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "accessibility_settings.h"
+
+#ifdef TV_PROFILE
+#include <system/system_settings.h>
+#endif
+
+#include "flutter/shell/platform/tizen/flutter_tizen_engine.h"
+#include "flutter/shell/platform/tizen/logger.h"
+
+// SYSTEM_SETTINGS_KEY_MENU_SYSTEM_ACCESSIBILITY_HIGHCONTRAST = 10059 has been
+// defined in system_settings_keys.h only for TV profile.
+#define SYSTEM_SETTINGS_KEY_MENU_SYSTEM_ACCESSIBILITY_HIGHCONTRAST 10059
+
+namespace flutter {
+
+AccessibilitySettings::AccessibilitySettings(FlutterTizenEngine* engine)
+    : engine_(engine) {
+#ifdef TV_PROFILE
+  // Add listener for accessibility high contrast.
+  system_settings_set_changed_cb(
+      system_settings_key_e(
+          SYSTEM_SETTINGS_KEY_MENU_SYSTEM_ACCESSIBILITY_HIGHCONTRAST),
+      [](system_settings_key_e key, void* user_data) -> void {
+        auto* self = reinterpret_cast<AccessibilitySettings*>(user_data);
+        self->OnHighContrastStateChanged();
+      },
+      this);
+
+  // Set initialized value of accessibility high contrast.
+  if (engine_ != nullptr) {
+    engine_->EnableAccessibilityFeature(GetHighContrastValue());
+  }
+#endif
+}
+
+AccessibilitySettings::~AccessibilitySettings() {
+#ifdef TV_PROFILE
+  system_settings_unset_changed_cb(system_settings_key_e(
+      SYSTEM_SETTINGS_KEY_MENU_SYSTEM_ACCESSIBILITY_HIGHCONTRAST));
+#endif
+}
+
+void AccessibilitySettings::OnHighContrastStateChanged() {
+  if (engine_ != nullptr) {
+    engine_->EnableAccessibilityFeature(GetHighContrastValue());
+  }
+}
+
+bool AccessibilitySettings::GetHighContrastValue() {
+  int enabled = 0;
+#ifdef TV_PROFILE
+  int ret = system_settings_get_value_int(
+      system_settings_key_e(
+          SYSTEM_SETTINGS_KEY_MENU_SYSTEM_ACCESSIBILITY_HIGHCONTRAST),
+      &enabled);
+  if (ret != SYSTEM_SETTINGS_ERROR_NONE) {
+    FT_LOG(Error)
+        << "Failed to get value of accessibility high contrast. ERROR CODE = "
+        << ret;
+  }
+#endif
+  return enabled;
+}
+
+}  // namespace flutter

shell/platform/tizen/accessibility_settings.h

@@ -0,0 +1,27 @@
+// Copyright 2022 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef EMBEDDER_ACCESSIBILITY_SETTINGS_H_
+#define EMBEDDER_ACCESSIBILITY_SETTINGS_H_
+
+namespace flutter {
+
+class FlutterTizenEngine;
+
+class AccessibilitySettings {
+ public:
+  explicit AccessibilitySettings(FlutterTizenEngine* engine);
+  virtual ~AccessibilitySettings();
+
+  void OnHighContrastStateChanged();
+
+ private:
+  bool GetHighContrastValue();
+
+  FlutterTizenEngine* engine_;
+};
+
+}  // namespace flutter
+
+#endif  // EMBEDDER_ACCESSIBILITY_SETTINGS_H_

shell/platform/tizen/flutter_tizen_engine.cc

@@ -270,6 +270,8 @@ bool FlutterTizenEngine::RunEngine(const char* entrypoint) {
     SetWindowOrientation(0);
   }
 
+  accessibility_settings_ = std::make_unique<AccessibilitySettings>(this);
+
   SetupLocales();
 
   return true;
@@ -473,6 +475,22 @@ bool FlutterTizenEngine::MarkExternalTextureFrameAvailable(int64_t texture_id) {
               engine_, texture_id) == kSuccess);
 }
 
+// Set bold font when accessibility high contrast state is
+// changed.
+void FlutterTizenEngine::EnableAccessibilityFeature(bool bold_text) {
+  if (engine_ == nullptr) {
+    return;
+  }
+
+  if (bold_text) {
+    embedder_api_.UpdateAccessibilityFeatures(
+        engine_, kFlutterAccessibilityFeatureBoldText);
+  } else {
+    embedder_api_.UpdateAccessibilityFeatures(engine_,
+                                              FlutterAccessibilityFeature(0));
+  }
+}
+
 // The Flutter Engine calls out to this function when new platform messages
 // are available.
 

shell/platform/tizen/flutter_tizen_engine.h

@@ -11,6 +11,7 @@
 #include "flutter/shell/platform/common/client_wrapper/include/flutter/plugin_registrar.h"
 #include "flutter/shell/platform/common/incoming_message_dispatcher.h"
 #include "flutter/shell/platform/embedder/embedder.h"
+#include "flutter/shell/platform/tizen/accessibility_settings.h"
 #include "flutter/shell/platform/tizen/channels/app_control_channel.h"
 #include "flutter/shell/platform/tizen/channels/key_event_channel.h"
 #include "flutter/shell/platform/tizen/channels/lifecycle_channel.h"
@@ -165,6 +166,9 @@ class FlutterTizenEngine : public TizenRenderer::Delegate {
   // given |texture_id|.
   bool MarkExternalTextureFrameAvailable(int64_t texture_id);
 
+  // Set bold font when accessibility high contrast state is changed.
+  void EnableAccessibilityFeature(bool bold_text);
+
  private:
   friend class EngineModifier;
 
@@ -245,6 +249,8 @@ class FlutterTizenEngine : public TizenRenderer::Delegate {
   // A plugin that implements the Tizen window channel.
   std::unique_ptr<WindowChannel> window_channel_;
 
+  std::unique_ptr<AccessibilitySettings> accessibility_settings_;
+
   // The event loop for the main thread that allows for delayed task execution.
   std::unique_ptr<TizenPlatformEventLoop> event_loop_;