[WIP][iOS]Add TextField OCR engine side support

lib/ui/platform_dispatcher.dart

@@ -860,6 +860,10 @@ class PlatformDispatcher {
   bool get brieflyShowPassword => _brieflyShowPassword;
   bool _brieflyShowPassword = true;
 
+  /// Indicates this device supports capture text from camera or not
+  bool get captureTextFromCameraEnabled => _captureTextFromCameraEnabled;
+  bool _captureTextFromCameraEnabled = false;
+
   /// The setting indicating the current brightness mode of the host platform.
   /// If the platform has no preference, [platformBrightness] defaults to
   /// [Brightness.light].
@@ -922,6 +926,11 @@ class PlatformDispatcher {
     if (brieflyShowPassword != null) {
       _brieflyShowPassword = brieflyShowPassword;
     }
+    // This field is optional.
+    final bool? captureTextFromCameraEnabled = data['captureTextFromCameraEnabled'] as bool?;
+    if (captureTextFromCameraEnabled != null) {
+      _captureTextFromCameraEnabled = captureTextFromCameraEnabled;
+    }
     final Brightness platformBrightness =
     data['platformBrightness']! as String == 'dark' ? Brightness.dark : Brightness.light;
     final String? systemFontFamily = data['systemFontFamily'] as String?;

lib/ui/window.dart

@@ -491,6 +491,12 @@ class SingletonFlutterWindow extends FlutterWindow {
     platformDispatcher.onPlatformBrightnessChanged = callback;
   }
 
+
+  /// A property that indicates this device support capture text from camera (OCR) or not
+  ///
+  /// If the device doesn't support OCR ,[captureTextFromCameraEnabled] is false
+  bool get captureTextFromCameraEnabled => platformDispatcher.captureTextFromCameraEnabled;
+
   /// The setting indicating the system font of the host platform.
   ///
   /// {@macro dart.ui.window.accessorForwardWarning}

lib/web_ui/lib/platform_dispatcher.dart

@@ -86,6 +86,8 @@ abstract class PlatformDispatcher {
 
   bool get brieflyShowPassword => true;
 
+  bool get captureTextFromCameraEnabled => false;
+
   VoidCallback? get onTextScaleFactorChanged;
   set onTextScaleFactorChanged(VoidCallback? callback);
 

lib/web_ui/lib/window.dart

@@ -52,6 +52,8 @@ abstract class SingletonFlutterWindow extends FlutterWindow {
 
   bool get brieflyShowPassword => platformDispatcher.brieflyShowPassword;
 
+  bool get captureTextFromCameraEnabled => platformDispatcher.captureTextFromCameraEnabled;
+
   bool get alwaysUse24HourFormat => platformDispatcher.alwaysUse24HourFormat;
 
   VoidCallback? get onTextScaleFactorChanged => platformDispatcher.onTextScaleFactorChanged;

shell/platform/darwin/ios/framework/Source/FlutterTextInputPlugin.mm

@@ -45,6 +45,8 @@
     @"TextInput.setEditableSizeAndTransform";
 static NSString* const kSetMarkedTextRectMethod = @"TextInput.setMarkedTextRect";
 static NSString* const kFinishAutofillContextMethod = @"TextInput.finishAutofillContext";
+static NSString* const kStartCapturingTextFromCameraMethod =
+    @"TextInput.startCapturingTextFromCamera";
 static NSString* const kSetSelectionRectsMethod = @"TextInput.setSelectionRects";
 
 #pragma mark - TextInputConfiguration Field Names
@@ -2089,6 +2091,9 @@ - (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
   } else if ([method isEqualToString:kSetSelectionRectsMethod]) {
     [self setSelectionRects:args];
     result(nil);
+  } else if ([method isEqualToString:kStartCapturingTextFromCameraMethod]) {
+    [self startCapturingTextFromCamera];
+    result(nil);
   } else {
     result(FlutterMethodNotImplemented);
   }
@@ -2170,6 +2175,15 @@ - (void)hideTextInput {
   [_inputHider removeFromSuperview];
 }
 
+- (void)startCapturingTextFromCamera {
+  if (_activeView == nil || !_activeView.isFirstResponder) {
+    return;
+  }
+  if (@available(iOS 15.0, *)) {
+    [_activeView captureTextFromCamera:nil];
+  }
+}
+
 - (void)triggerAutofillSave:(BOOL)saveEntries {
   [_activeView resignFirstResponder];
 

shell/platform/darwin/ios/framework/Source/FlutterTextInputPluginTest.mm

@@ -68,6 +68,7 @@ - (void)cleanUpViewHierarchy:(BOOL)includeActiveView
 - (UIView*)hostView;
 - (fml::WeakPtr<FlutterTextInputPlugin>)getWeakPtr;
 - (void)addToInputParentViewIfNeeded:(FlutterTextInputView*)inputView;
+- (void)startCapturingTextFromCamera;
 @end
 
 @interface FlutterTextInputPluginTest : XCTestCase
@@ -165,6 +166,18 @@ - (FlutterTextRange*)getLineRangeFromTokenizer:(id<UITextInputTokenizer>)tokeniz
 }
 
 #pragma mark - Tests
+
+- (void)testInvokeStartCapturingTextFromCamera {
+  FlutterMethodCall* methodCall =
+      [FlutterMethodCall methodCallWithMethodName:@"TextInput.startCapturingTextFromCamera"
+                                        arguments:nil];
+  FlutterTextInputPlugin* mockPlugin = OCMPartialMock(textInputPlugin);
+  [mockPlugin handleMethodCall:methodCall
+                        result:^(id _Nullable result){
+                        }];
+  OCMVerify([mockPlugin startCapturingTextFromCamera]);
+}
+
 - (void)testNoDanglingEnginePointer {
   __weak FlutterTextInputPlugin* weakFlutterTextInputPlugin;
   FlutterViewController* flutterViewController = [FlutterViewController new];

shell/platform/darwin/ios/framework/Source/FlutterViewController.mm

@@ -110,6 +110,10 @@ @implementation FlutterViewController {
   fml::scoped_nsobject<UIPanGestureRecognizer> _panGestureRecognizer API_AVAILABLE(ios(13.4));
   fml::scoped_nsobject<UIView> _keyboardAnimationView;
   MouseState _mouseState;
+
+  // This textField is to judge whether this device supports caputureTextFromCamera API or not.
+  // See method "captureTextFromCameraEnabled"
+  fml::scoped_nsobject<UITextField> _textField;
 }
 
 @synthesize displayingFlutterUI = _displayingFlutterUI;
@@ -624,6 +628,14 @@ - (void)setSplashScreenView:(UIView*)view {
       UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
 }
 
+- (UITextField*)textField {
+  if (_textField.get() == nil) {
+    UITextField* newTextField = [[UITextField alloc] init];
+    _textField.reset(newTextField);
+  }
+  return _textField.get();
+}
+
 - (void)setFlutterViewDidRenderCallback:(void (^)(void))callback {
   _flutterViewRenderedCallback.reset(callback, fml::OwnershipPolicy::Retain);
 }
@@ -1512,7 +1524,8 @@ - (void)onUserSettingsChanged:(NSNotification*)notification {
     @"textScaleFactor" : @([self textScaleFactor]),
     @"alwaysUse24HourFormat" : @([self isAlwaysUse24HourFormat]),
     @"platformBrightness" : [self brightnessMode],
-    @"platformContrast" : [self contrastMode]
+    @"platformContrast" : [self contrastMode],
+    @"captureTextFromCameraEnabled" : @([self captureTextFromCameraEnabled]),
   }];
 }
 
@@ -1621,6 +1634,11 @@ - (NSString*)contrastMode {
   }
 }
 
+- (BOOL)captureTextFromCameraEnabled {
+  UITextField* textField = [self textField];
+  return [textField canPerformAction:@selector(captureTextFromCamera:) withSender:nil];
+}
+
 #pragma mark - Status bar style
 
 - (UIStatusBarStyle)preferredStatusBarStyle {

shell/platform/darwin/ios/framework/Source/FlutterViewControllerTest.mm

@@ -143,6 +143,7 @@ - (void)startKeyBoardAnimation:(NSTimeInterval)duration;
 - (void)ensureViewportMetricsIsCorrect;
 - (void)invalidateDisplayLink;
 - (void)addInternalPlugins;
+- (BOOL)captureTextFromCameraEnabled;
 - (flutter::PointerData)generatePointerDataForFake;
 @end
 
@@ -171,6 +172,18 @@ - (void)tearDown {
   self.messageSent = nil;
 }
 
+- (void)testOnUserSettingsChangedWillInvokeCaptureTextFromCameraEnabled {
+  FlutterEngine* mockEngine = OCMPartialMock([[FlutterEngine alloc] init]);
+  [mockEngine createShell:@"" libraryURI:@"" initialRoute:nil];
+  FlutterViewController* viewController = [[FlutterViewController alloc] initWithEngine:mockEngine
+                                                                                nibName:nil
+                                                                                 bundle:nil];
+  FlutterViewController* viewControllerMock = OCMPartialMock(viewController);
+  NSNotification* fakeNotification = [NSNotification notificationWithName:@"" object:nil];
+  [viewControllerMock onUserSettingsChanged:fakeNotification];
+  OCMVerify([viewControllerMock captureTextFromCameraEnabled]);
+}
+
 - (void)testkeyboardWillChangeFrameWillStartKeyboardAnimation {
   FlutterEngine* mockEngine = OCMPartialMock([[FlutterEngine alloc] init]);
   [mockEngine createShell:@"" libraryURI:@"" initialRoute:nil];