Support text direction rtl

lib/src/models/documents/attribute.dart

@@ -79,6 +79,8 @@ class Attribute<T> {
 
   static final BlockQuoteAttribute blockQuote = BlockQuoteAttribute();
 
+  static final DirectionAttribute direction = DirectionAttribute(null);
+
   static final WidthAttribute width = WidthAttribute(null);
 
   static final HeightAttribute height = HeightAttribute(null);
@@ -116,6 +118,7 @@ class Attribute<T> {
     Attribute.codeBlock.key,
     Attribute.blockQuote.key,
     Attribute.indent.key,
+    Attribute.direction.key,
   });
 
   static final Set<String> blockKeysExceptHeader = LinkedHashSet.of({
@@ -124,6 +127,7 @@ class Attribute<T> {
     Attribute.codeBlock.key,
     Attribute.blockQuote.key,
     Attribute.indent.key,
+    Attribute.direction.key,
   });
 
   static final Set<String> exclusiveBlockKeys = LinkedHashSet.of({
@@ -163,6 +167,9 @@ class Attribute<T> {
   // "attributes":{"list":"unchecked"}
   static Attribute<String?> get unchecked => ListAttribute('unchecked');
 
+  // "attributes":{"direction":"rtl"}
+  static Attribute<String?> get rtl => DirectionAttribute('rtl');
+
   // "attributes":{"indent":1"}
   static Attribute<int?> get indentL1 => IndentAttribute(level: 1);
 
@@ -309,6 +316,11 @@ class BlockQuoteAttribute extends Attribute<bool> {
   BlockQuoteAttribute() : super('blockquote', AttributeScope.BLOCK, true);
 }
 
+class DirectionAttribute extends Attribute<String?> {
+  DirectionAttribute(String? val)
+      : super('direction', AttributeScope.BLOCK, val);
+}
+
 class WidthAttribute extends Attribute<String?> {
   WidthAttribute(String? val) : super('width', AttributeScope.IGNORE, val);
 }

lib/src/utils/delta.dart

@@ -1,5 +1,8 @@
 import 'dart:math' as math;
+import 'dart:ui';
 
+import '../models/documents/attribute.dart';
+import '../models/documents/nodes/node.dart';
 import '../models/quill_delta.dart';
 
 // Diff between two texts - old text and new text
@@ -72,3 +75,11 @@ int getPositionDelta(Delta user, Delta actual) {
   }
   return diff;
 }
+
+TextDirection getDirectionOfNode(Node node) {
+  final direction = node.style.attributes[Attribute.direction.key];
+  if (direction == Attribute.rtl) {
+    return TextDirection.rtl;
+  }
+  return TextDirection.ltr;
+}

lib/src/widgets/raw_editor.dart

@@ -19,6 +19,7 @@ import '../models/documents/nodes/embeddable.dart';
 import '../models/documents/nodes/line.dart';
 import '../models/documents/nodes/node.dart';
 import '../models/documents/style.dart';
+import '../utils/delta.dart';
 import '../utils/platform.dart';
 import 'controller.dart';
 import 'cursor.dart';
@@ -436,7 +437,8 @@ class RawEditorState extends EditorState
     for (final node in doc.root.children) {
       if (node is Line) {
         final editableTextLine = _getEditableTextLineFromNode(node, context);
-        result.add(editableTextLine);
+        result.add(Directionality(
+            textDirection: getDirectionOfNode(node), child: editableTextLine));
       } else if (node is Block) {
         final attrs = node.style.attributes;
         final editableTextBlock = EditableTextBlock(
@@ -461,7 +463,8 @@ class RawEditorState extends EditorState
             onCheckboxTap: _handleCheckboxTap,
             readOnly: widget.readOnly,
             customStyleBuilder: widget.customStyleBuilder);
-        result.add(editableTextBlock);
+        result.add(Directionality(
+            textDirection: getDirectionOfNode(node), child: editableTextBlock));
       } else {
         throw StateError('Unreachable.');
       }

lib/src/widgets/text_block.dart

@@ -5,6 +5,7 @@ import 'package:tuple/tuple.dart';
 import '../../flutter_quill.dart';
 import '../models/documents/nodes/block.dart';
 import '../models/documents/nodes/line.dart';
+import '../utils/delta.dart';
 import 'box.dart';
 import 'cursor.dart';
 import 'delegate.dart';
@@ -146,7 +147,9 @@ class EditableTextBlock extends StatelessWidget {
           hasFocus,
           MediaQuery.of(context).devicePixelRatio,
           cursorCont);
-      children.add(editableTextLine);
+      final nodeTextDirection = getDirectionOfNode(line);
+      children.add(Directionality(
+          textDirection: nodeTextDirection, child: editableTextLine));
     }
     return children.toList(growable: false);
   }

lib/src/widgets/toolbar.dart

@@ -100,6 +100,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
     bool showImageButton = true,
     bool showVideoButton = true,
     bool showCameraButton = true,
+    bool showDirection = false,
     OnImagePickCallback? onImagePickCallback,
     OnVideoPickCallback? onVideoPickCallback,
     MediaPickSettingSelector? mediaPickSettingSelector,
@@ -131,7 +132,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
           showClearFormat ||
           onImagePickCallback != null ||
           onVideoPickCallback != null,
-      showAlignmentButtons,
+      showAlignmentButtons || showDirection,
       showLeftAlignment,
       showCenterAlignment,
       showRightAlignment,
@@ -296,6 +297,14 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
             showRightAlignment: showRightAlignment,
             showJustifyAlignment: showJustifyAlignment,
           ),
+        if (showDirection)
+          ToggleStyleButton(
+            attribute: Attribute.rtl,
+            controller: controller,
+            icon: Icons.format_textdirection_r_to_l,
+            iconSize: toolbarIconSize,
+            iconTheme: iconTheme,
+          ),
         if (showDividers &&
             isButtonGroupShown[1] &&
             (isButtonGroupShown[2] ||