Parsing image caption & alt (flutter#232)

Author: anggriyulio

packages/flutter_markdown/lib/src/builder.dart

@@ -307,7 +307,7 @@ class MarkdownBuilder implements md.NodeVisitor {
 
       if (tag == 'img') {
         // create an image widget for this image
-        current.children.add(_buildImage(element.attributes['src']));
+        current.children.add(_buildImage(element.attributes['src'],element.attributes['title'],element.attributes['alt'],));
       } else if (tag == 'br') {
         current.children.add(_buildRichText(const TextSpan(text: '\n')));
       } else if (tag == 'th' || tag == 'td') {
@@ -346,7 +346,7 @@ class MarkdownBuilder implements md.NodeVisitor {
     if (_currentBlockTag == tag) _currentBlockTag = null;
   }
 
-  Widget _buildImage(String src) {
+  Widget _buildImage(String src, String title, String alt) {
     final List<String> parts = src.split('#');
     if (parts.isEmpty) return const SizedBox();
 
@@ -364,7 +364,7 @@ class MarkdownBuilder implements md.NodeVisitor {
     Uri uri = Uri.parse(path);
     Widget child;
     if (imageBuilder != null) {
-      child = imageBuilder(uri);
+      child = imageBuilder(uri, title, alt);
     } else {
       child = kDefaultImageBuilder(uri, imageDirectory, width, height);
     }

packages/flutter_markdown/lib/src/widget.dart

@@ -20,7 +20,7 @@ typedef void MarkdownTapLinkCallback(String href);
 /// Signature for custom image widget.
 ///
 /// Used by [MarkdownWidget.imageBuilder]
-typedef Widget MarkdownImageBuilder(Uri uri);
+typedef Widget MarkdownImageBuilder(Uri uri, String title, String alt);
 
 /// Signature for custom checkbox widget.
 ///

packages/flutter_markdown/test/flutter_markdown_test.dart

@@ -738,7 +738,7 @@ void main() {
     testWidgets(' - imageBuilder', (WidgetTester tester) async {
       final String data = '![alt](https://img.png)';
       final MarkdownImageBuilder builder =
-          (_) => Image.asset('assets/logo.png');
+          (_, __, ___) => Image.asset('assets/logo.png');
 
       await tester.pumpWidget(
           _boilerplate(Markdown(data: data, imageBuilder: builder)));