Add image handling and dimension parsing to renderer

src/Blake.MarkdownParser/ImageCaptionRenderer.cs

@@ -1,30 +1,54 @@
-using System.Text;
 using Markdig.Renderers;
 using Markdig.Renderers.Html;
 using Markdig.Syntax.Inlines;
+using System.Text;
+using System.Text.RegularExpressions;
 
 namespace Blake.MarkdownParser;
 
-
-public class ImageCaptionRenderer : HtmlObjectRenderer<LinkInline>
+public partial class ImageCaptionRenderer : HtmlObjectRenderer<LinkInline>
 {
+    private static readonly Regex _shorthandDimensionsRegex = ShorthandRegex();
+
     protected override void Write(HtmlRenderer renderer, LinkInline link)
     {
         if (link.IsImage)
         {
-
             var caption = link.FirstChild?.ToString() ?? "";
-            var src = link.Url?.Trim() ?? "";
+            var originalSrc = link.Url?.Trim() ?? "";
+
+            // Parse shorthand dimensions from URL (e.g., "/image.png =200x300")
+            var (src, shorthandWidth, shorthandHeight) = ParseShorthandDimensions(originalSrc);
 
             // Read GenericAttributes
             var attrs = link.TryGetAttributes();
 
+            // Apply shorthand dimensions if no explicit width/height attributes are present
+            if (attrs == null)
+            {
+                attrs = new HtmlAttributes();
+            }
+
+            // Only apply shorthand if no explicit dimensions are set via generic attributes
+            var hasExplicitWidth = attrs.Properties?.Any(p => p.Key == "width") ?? false;
+            var hasExplicitHeight = attrs.Properties?.Any(p => p.Key == "height") ?? false;
+
+            if (!hasExplicitWidth && shorthandWidth.HasValue)
+            {
+                attrs.AddProperty("width", shorthandWidth.Value.ToString());
+            }
+
+            if (!hasExplicitHeight && shorthandHeight.HasValue)
+            {
+                attrs.AddProperty("height", shorthandHeight.Value.ToString());
+            }
+
             // Build attribute string
             var attrString = BuildAttributeString(attrs);
 
             // Fallback style if no explicit width or style
-            var hasWidth = attrs?.Properties?.Any(p => p.Key == "width") ?? false;
-            var hasStyle = attrs?.Properties?.Any(p => p.Key == "style") ?? false;
+            var hasWidth = attrs.Properties?.Any(p => p.Key == "width") ?? false;
+            var hasStyle = attrs.Properties?.Any(p => p.Key == "style") ?? false;
             if (!hasWidth && !hasStyle)
             {
                 attrString += " style=\"max-width:100%;height:auto;\"";
@@ -52,7 +76,7 @@ private string BuildAttributeString(HtmlAttributes? attrs)
 
         var sb = new StringBuilder();
 
-        foreach (var prop in attrs?.Properties?? [])
+        foreach (var prop in attrs?.Properties ?? [])
         {
             var safeName = HtmlEscape(prop.Key);
             var safeValue = HtmlEscape(prop.Value ?? "");
@@ -62,6 +86,44 @@ private string BuildAttributeString(HtmlAttributes? attrs)
         return sb.ToString();
     }
 
+    private static (string cleanUrl, int? width, int? height) ParseShorthandDimensions(string url)
+    {
+        var match = _shorthandDimensionsRegex.Match(url);
+        if (!match.Success)
+        {
+            return (url, null, null);
+        }
+
+        var cleanUrl = url.Substring(0, match.Index).Trim();
+
+        var widthGroup = match.Groups[1];
+        var heightGroup = match.Groups[2];
+
+        int? width = null;
+        int? height = null;
+
+        if (widthGroup.Success && !string.IsNullOrEmpty(widthGroup.Value))
+        {
+            if (int.TryParse(widthGroup.Value, out var w))
+            {
+                width = w;
+            }
+        }
+
+        if (heightGroup.Success && !string.IsNullOrEmpty(heightGroup.Value))
+        {
+            if (int.TryParse(heightGroup.Value, out var h))
+            {
+                height = h;
+            }
+        }
+
+        return (cleanUrl, width, height);
+    }
+
     private static string HtmlEscape(string input) =>
         System.Net.WebUtility.HtmlEncode(input);
-}
+
+    [GeneratedRegex(@"\s*=(\d*)?x(\d*)?\s*$", RegexOptions.Compiled)]
+    private static partial Regex ShorthandRegex();
+}