support for custom styling property and height calculation bug cleared

app/lib/widgets/field.dart

@@ -24,7 +24,7 @@ class QuillField extends StatefulWidget {
   final InputDecoration decoration;
   final Widget toolbar;
   final EmbedBuilder embedBuilder;
-
+  final StyleBuilder styleBuilder;
   QuillField({
     Key key,
     @required this.controller,
@@ -45,7 +45,7 @@ class QuillField extends StatefulWidget {
     this.onLaunchUrl,
     this.decoration,
     this.toolbar,
-    this.embedBuilder,
+    this.embedBuilder, this.styleBuilder,
   }) : super(key: key);
 
   @override
@@ -98,6 +98,7 @@ class _QuillFieldState extends State<QuillField> {
       scrollPhysics: widget.scrollPhysics,
       onLaunchUrl: widget.onLaunchUrl,
       embedBuilder: widget.embedBuilder,
+      styleBuilder:widget.styleBuilder,
     );
 
     if (widget.toolbar != null) {

lib/widgets/delegate.dart

@@ -3,12 +3,13 @@ import 'package:flutter/gestures.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_quill/models/documents/nodes/leaf.dart';
+import 'package:flutter_quill/models/documents/attribute.dart';
 import 'package:flutter_quill/widgets/text_selection.dart';
 
 import 'editor.dart';
 
 typedef EmbedBuilder = Widget Function(BuildContext context, Embed node);
-
+typedef StyleBuilder = TextStyle Function(Attribute<dynamic> attribute);
 abstract class EditorTextSelectionGestureDetectorBuilderDelegate {
   GlobalKey<EditorState> getEditableTextKey();
 

lib/widgets/editor.dart

@@ -144,7 +144,7 @@ class QuillEditor extends StatefulWidget {
   final ScrollPhysics scrollPhysics;
   final ValueChanged<String> onLaunchUrl;
   final EmbedBuilder embedBuilder;
-
+  final StyleBuilder styleBuilder;
   QuillEditor(
       {@required this.controller,
       @required this.focusNode,
@@ -164,7 +164,7 @@ class QuillEditor extends StatefulWidget {
       this.scrollPhysics,
       this.onLaunchUrl,
       this.embedBuilder =
-          kIsWeb ? _defaultEmbedBuilderWeb : _defaultEmbedBuilder})
+          kIsWeb ? _defaultEmbedBuilderWeb : _defaultEmbedBuilder, this.styleBuilder})
       : assert(controller != null),
         assert(scrollController != null),
         assert(scrollable != null),
@@ -286,7 +286,9 @@ class _QuillEditorState extends State<QuillEditor>
           widget.keyboardAppearance,
           widget.enableInteractiveSelection,
           widget.scrollPhysics,
-          widget.embedBuilder),
+          widget.embedBuilder,
+          widget.styleBuilder,
+          ),
     );
   }
 

lib/widgets/raw_editor.dart

@@ -49,7 +49,7 @@ class RawEditor extends StatefulWidget {
   final bool enableInteractiveSelection;
   final ScrollPhysics scrollPhysics;
   final EmbedBuilder embedBuilder;
-
+final StyleBuilder styleBuilder;
   RawEditor(
       Key key,
       this.controller,
@@ -74,7 +74,7 @@ class RawEditor extends StatefulWidget {
       this.keyboardAppearance,
       this.enableInteractiveSelection,
       this.scrollPhysics,
-      this.embedBuilder)
+      this.embedBuilder, this.styleBuilder)
       : assert(controller != null, 'controller cannot be null'),
         assert(focusNode != null, 'focusNode cannot be null'),
         assert(scrollable || scrollController != null,
@@ -571,6 +571,7 @@ class RawEditorState extends EditorState
           line: node,
           textDirection: _textDirection,
           embedBuilder: widget.embedBuilder,
+          styleBuilder:widget.styleBuilder,
           styles: _styles,
         );
         EditableTextLine editableTextLine = EditableTextLine(

lib/widgets/text_line.dart

@@ -25,10 +25,16 @@ class TextLine extends StatelessWidget {
   final Line line;
   final TextDirection textDirection;
   final EmbedBuilder embedBuilder;
+  final StyleBuilder styleBuilder;
   final DefaultStyles styles;
 
   const TextLine(
-      {Key key, this.line, this.textDirection, this.embedBuilder, this.styles})
+      {Key key,
+      this.line,
+      this.textDirection,
+      this.embedBuilder,
+      this.styles,
+      this.styleBuilder})
       : assert(line != null),
         assert(embedBuilder != null),
         assert(styles != null),
@@ -43,12 +49,12 @@ class TextLine extends StatelessWidget {
       return EmbedProxy(embedBuilder(context, embed));
     }
 
-    TextSpan textSpan = _buildTextSpan(context);
+    TextSpan textSpan = _buildTextSpan(context, styleBuilder);
     StrutStyle strutStyle =
         StrutStyle.fromTextStyle(textSpan.style, forceStrutHeight: true);
     final textAlign = _getTextAlign();
     RichText child = RichText(
-      text: _buildTextSpan(context),
+      text: TextSpan(children: [_buildTextSpan(context,styleBuilder)]),
       textAlign: textAlign,
       textDirection: textDirection,
       strutStyle: strutStyle,
@@ -80,10 +86,10 @@ class TextLine extends StatelessWidget {
     return TextAlign.start;
   }
 
-  TextSpan _buildTextSpan(BuildContext context) {
+  TextSpan _buildTextSpan(BuildContext context, StyleBuilder styleBuilder) {
     DefaultStyles defaultStyles = styles;
     List<TextSpan> children = line.children
-        .map((node) => _getTextSpanFromNode(defaultStyles, node))
+        .map((node) => _getTextSpanFromNode(defaultStyles, node, styleBuilder))
         .toList(growable: false);
 
     TextStyle textStyle = TextStyle();
@@ -112,7 +118,8 @@ class TextLine extends StatelessWidget {
     return TextSpan(children: children, style: textStyle);
   }
 
-  TextSpan _getTextSpanFromNode(DefaultStyles defaultStyles, Node node) {
+  TextSpan _getTextSpanFromNode(
+      DefaultStyles defaultStyles, Node node, StyleBuilder styleBuilder) {
     leaf.Text textNode = node as leaf.Text;
     Style style = textNode.style;
     TextStyle res = TextStyle();
@@ -137,7 +144,6 @@ class TextLine extends StatelessWidget {
 
     Attribute size = textNode.style.attributes[Attribute.size.key];
     if (size != null && size.value != null) {
-
       switch (size.value) {
         case 'small':
           res = res.merge(defaultStyles.sizeSmall);
@@ -150,11 +156,10 @@ class TextLine extends StatelessWidget {
           break;
         default:
           double fontSize = double.tryParse(size.value);
-          if(fontSize!=null){
+          if (fontSize != null) {
             res = res.merge(TextStyle(fontSize: fontSize));
-          }
+          } else
-          else
+            throw "Invalid size ${size.value}";
-          throw "Invalid size ${size.value}";
       }
     }
 
@@ -169,7 +174,16 @@ class TextLine extends StatelessWidget {
       final backgroundColor = stringToColor(background.value);
       res = res.merge(new TextStyle(backgroundColor: backgroundColor));
     }
-
+    if (styleBuilder != null)
+      textNode.style.attributes.keys.forEach((key) {
+        Attribute attribute =
+            Attribute.fromKeyValue(key, textNode.style.attributes[key]);
+        if (attribute == null) {
+          ///Unkown Attribute
+          TextStyle customStyle = styleBuilder( textNode.style.attributes[key]);
+          if (customStyle != null) res = res.merge(customStyle);
+        }
+      });
     return TextSpan(text: textNode.value, style: res);
   }