Ignore attributes of width and style

app/assets/sample_data.json

@@ -10,7 +10,11 @@
    },
    {
       "insert": {
-         "image":"https://user-images.githubusercontent.com/122956/72955931-ccc07900-3d52-11ea-89b1-d468a6e2aa2b.png"
+         "image": "https://user-images.githubusercontent.com/122956/72955931-ccc07900-3d52-11ea-89b1-d468a6e2aa2b.png"
+      },
+      "attributes":{
+         "width":"230",
+         "style":"display: block; margin: auto;"
       }
    },
    {

lib/models/documents/attribute.dart

@@ -4,6 +4,7 @@ enum AttributeScope {
   INLINE, // refer to https://quilljs.com/docs/formats/#inline
   BLOCK, // refer to https://quilljs.com/docs/formats/#block
   EMBEDS, // refer to https://quilljs.com/docs/formats/#embeds
+  IGNORE, // atttributes that can be igored
 }
 
 class Attribute<T> {
@@ -27,6 +28,9 @@ class Attribute<T> {
     Attribute.list.key: Attribute.list,
     Attribute.codeBlock.key: Attribute.codeBlock,
     Attribute.blockQuote.key: Attribute.blockQuote,
+    Attribute.width.key: Attribute.width,
+    Attribute.height.key: Attribute.height,
+    Attribute.style.key: Attribute.style,
   };
 
   static final BoldAttribute bold = BoldAttribute();
@@ -55,6 +59,12 @@ class Attribute<T> {
 
   static final BlockQuoteAttribute blockQuote = BlockQuoteAttribute();
 
+  static final WidthAttribute width = WidthAttribute(null);
+
+  static final HeightAttribute height = HeightAttribute(null);
+
+  static final StyleAttribute style = StyleAttribute(null);
+
   static final Set<String> inlineKeys = {
     Attribute.bold.key,
     Attribute.italic.key,
@@ -196,3 +206,15 @@ class CodeBlockAttribute extends Attribute<bool> {
 class BlockQuoteAttribute extends Attribute<bool> {
   BlockQuoteAttribute() : super('blockquote', AttributeScope.BLOCK, true);
 }
+
+class WidthAttribute extends Attribute<String> {
+  WidthAttribute(String val) : super('width', AttributeScope.IGNORE, val);
+}
+
+class HeightAttribute extends Attribute<String> {
+  HeightAttribute(String val) : super('height', AttributeScope.IGNORE, val);
+}
+
+class StyleAttribute extends Attribute<String> {
+  StyleAttribute(String val) : super('style', AttributeScope.IGNORE, val);
+}

lib/models/documents/nodes/leaf.dart

@@ -30,7 +30,7 @@ abstract class Leaf extends Node {
 
   @override
   void applyStyle(Style value) {
-    assert(value != null && (value.isInline || value.isEmpty),
+    assert(value != null && (value.isInline || value.isIgnored || value.isEmpty),
         'Unable to apply Style to leaf: $value');
     super.applyStyle(value);
   }

lib/models/documents/style.dart

@@ -39,6 +39,9 @@ class Style {
 
   bool get isInline => isNotEmpty && values.every((item) => item.isInline);
 
+  bool get isIgnored =>
+      isNotEmpty && values.every((item) => item.scope == AttributeScope.IGNORE);
+
   Attribute get single => _attributes.values.single;
 
   bool containsKey(String key) => _attributes.containsKey(key);