🐛 Fixes on post compose

lib/widgets/content/markdown.dart

@@ -2,10 +2,13 @@ import 'package:auto_route/auto_route.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:flutter_highlight/themes/a11y-dark.dart';
+import 'package:flutter_highlight/themes/a11y-light.dart';
 import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:island/pods/config.dart';
 import 'package:island/widgets/alert.dart';
+import 'package:island/widgets/content/markdown_latex.dart';
 import 'package:markdown/markdown.dart' as markdown;
 import 'package:markdown_widget/markdown_widget.dart';
 import 'package:url_launcher/url_launcher.dart';
@@ -18,6 +21,7 @@ class MarkdownTextContent extends HookConsumerWidget {
   final TextScaler? textScaler;
   final TextStyle? textStyle;
   final TextStyle? linkStyle;
+  final EdgeInsets? linesMargin;
   final bool isSelectable;
 
   const MarkdownTextContent({
@@ -28,6 +32,7 @@ class MarkdownTextContent extends HookConsumerWidget {
     this.textStyle,
     this.linkStyle,
     this.isSelectable = false,
+    this.linesMargin,
   });
 
   @override
@@ -54,19 +59,13 @@ class MarkdownTextContent extends HookConsumerWidget {
       config: config.copy(
         configs: [
           isDark
-              ? PreConfig.darkConfig.copy(
-                textStyle: textStyle,
-                padding: EdgeInsets.zero,
-                margin: EdgeInsets.zero,
-              )
-              : PreConfig().copy(
-                textStyle: textStyle,
-                padding: EdgeInsets.zero,
-                margin: EdgeInsets.zero,
-              ),
+              ? PreConfig.darkConfig.copy(textStyle: textStyle)
+              : PreConfig().copy(textStyle: textStyle),
           PConfig(
             textStyle: textStyle ?? Theme.of(context).textTheme.bodyMedium!,
           ),
+          HrConfig(height: 1, color: Theme.of(context).dividerColor),
+          PreConfig(theme: isDark ? a11yDarkTheme : a11yLightTheme),
           LinkConfig(
             style:
                 linkStyle ??
@@ -146,8 +145,13 @@ class MarkdownTextContent extends HookConsumerWidget {
         ],
       ),
       generator: MarkdownGenerator(
-        inlineSyntaxList: [_UserNameCardInlineSyntax(), _StickerInlineSyntax()],
-        linesMargin: EdgeInsets.zero,
+        generators: [latexGenerator],
+        inlineSyntaxList: [
+          _UserNameCardInlineSyntax(),
+          _StickerInlineSyntax(),
+          LatexSyntax(isDark),
+        ],
+        linesMargin: linesMargin ?? EdgeInsets.symmetric(vertical: 4),
       ),
     );
   }

lib/widgets/content/markdown_latex.dart

@@ -0,0 +1,80 @@
+import 'package:flutter/material.dart';
+import 'package:markdown_widget/markdown_widget.dart';
+import 'package:flutter_math_fork/flutter_math.dart';
+import 'package:markdown/markdown.dart' as m;
+
+SpanNodeGeneratorWithTag latexGenerator = SpanNodeGeneratorWithTag(
+  tag: _latexTag,
+  generator:
+      (e, config, visitor) => LatexNode(e.attributes, e.textContent, config),
+);
+
+const _latexTag = 'latex';
+
+class LatexSyntax extends m.InlineSyntax {
+  final bool isDark;
+  LatexSyntax(this.isDark) : super(r'(\$\$[\s\S]+\$\$)|(\$.+?\$)');
+
+  @override
+  bool onMatch(m.InlineParser parser, Match match) {
+    final input = match.input;
+    final matchValue = input.substring(match.start, match.end);
+    String content = '';
+    bool isInline = true;
+    const blockSyntax = '\$\$';
+    const inlineSyntax = '\$';
+    if (matchValue.startsWith(blockSyntax) &&
+        matchValue.endsWith(blockSyntax) &&
+        (matchValue != blockSyntax)) {
+      content = matchValue.substring(2, matchValue.length - 2);
+      isInline = false;
+    } else if (matchValue.startsWith(inlineSyntax) &&
+        matchValue.endsWith(inlineSyntax) &&
+        matchValue != inlineSyntax) {
+      content = matchValue.substring(1, matchValue.length - 1);
+    }
+    m.Element el = m.Element.text(_latexTag, matchValue);
+    el.attributes['content'] = content;
+    el.attributes['isInline'] = '$isInline';
+    el.attributes['isDark'] = isDark.toString();
+    parser.addNode(el);
+    return true;
+  }
+}
+
+class LatexNode extends SpanNode {
+  final Map<String, String> attributes;
+  final String textContent;
+  final MarkdownConfig config;
+
+  LatexNode(this.attributes, this.textContent, this.config);
+
+  @override
+  InlineSpan build() {
+    final content = attributes['content'] ?? '';
+    final isInline = attributes['isInline'] == 'true';
+    final isDark = attributes['isDark'] == 'true';
+    final style = parentStyle ?? config.p.textStyle;
+    if (content.isEmpty) return TextSpan(style: style, text: textContent);
+    final latex = Math.tex(
+      content,
+      mathStyle: MathStyle.text,
+      textStyle: style.copyWith(color: isDark ? Colors.white : Colors.black),
+      textScaleFactor: 1,
+      onErrorFallback: (error) {
+        return Text(textContent, style: style.copyWith(color: Colors.red));
+      },
+    );
+    return WidgetSpan(
+      alignment: PlaceholderAlignment.middle,
+      child:
+          !isInline
+              ? Container(
+                width: double.infinity,
+                margin: EdgeInsets.symmetric(vertical: 16),
+                child: Center(child: latex),
+              )
+              : latex,
+    );
+  }
+}