Add ConfigureHtmlRenderer to MarkdownPipelineBuilder

src/Markdig.Tests/RoundtripSpecs/Inlines/TestNullCharacterInline.cs

@@ -22,16 +22,15 @@ public void Test(string value, string expected)
         // do not unintentionally use the expected parameter
         private static void RoundTrip(string markdown, string expected)
         {
-            var pipelineBuilder = new MarkdownPipelineBuilder();
-            pipelineBuilder.EnableTrackTrivia();
-            MarkdownPipeline pipeline = pipelineBuilder.Build();
-            MarkdownDocument markdownDocument = Markdown.Parse(markdown, pipeline);
-            var sw = new StringWriter();
-            var rr = new RoundtripRenderer(sw);
+            var pipeline = new MarkdownPipelineBuilder()
+                .EnableTrackTrivia()
+                .ConfigureRoundtripRenderer()
+                .Build();
 
-            rr.Write(markdownDocument);
+            MarkdownDocument markdownDocument = Markdown.Parse(markdown, pipeline);
+            var result = Markdown.ToHtml(markdownDocument, pipeline);
 
-            Assert.AreEqual(expected, sw.ToString());
+            Assert.AreEqual(expected, result);
         }
     }
 }

src/Markdig.Tests/TestLinkRewriter.cs

@@ -24,17 +24,13 @@ public void ReplacesRelativeImageSources()
 
     public static void TestSpec(Func<string,string> linkRewriter, string markdown, string expectedLink)
     {
-        var pipeline = new MarkdownPipelineBuilder().Build();
-
-        var writer = new StringWriter();
-        var renderer = new HtmlRenderer(writer);
-        renderer.LinkRewriter = linkRewriter;
-        pipeline.Setup(renderer);
+        var pipeline = new MarkdownPipelineBuilder()
+            .ConfigureHtmlRenderer(r => r.UseLinkRewriter(linkRewriter))
+            .Build();
 
         var document = MarkdownParser.Parse(markdown, pipeline);
-        renderer.Render(document);
-        writer.Flush();
+        var html = Markdown.ToHtml(document, pipeline);
 
-        Assert.That(writer.ToString(), Contains.Substring("=\"" + expectedLink + "\""));
+        Assert.That(html, Contains.Substring("=\"" + expectedLink + "\""));
     }
 }

src/Markdig.Tests/TestRelativeUrlReplacement.cs

@@ -27,18 +27,13 @@ public void ReplacesRelativeImageSources()
 
     public static void TestSpec(string baseUrl, string markdown, string expectedLink)
     {
-        var pipeline = new MarkdownPipelineBuilder().Build();
-
-        var writer = new StringWriter();
-        var renderer = new HtmlRenderer(writer);
-        if (baseUrl != null)
-            renderer.BaseUrl = new Uri(baseUrl);
-        pipeline.Setup(renderer);
+        var pipeline = new MarkdownPipelineBuilder()
+            .ConfigureHtmlRenderer(b => b.UseBaseUrl(baseUrl))
+            .Build();
 
         var document = MarkdownParser.Parse(markdown, pipeline);
-        renderer.Render(document);
-        writer.Flush();
+        var html = Markdown.ToHtml(document, pipeline);
 
-        Assert.That(writer.ToString(), Contains.Substring("=\"" + expectedLink + "\""));
+        Assert.That(html, Contains.Substring("=\"" + expectedLink + "\""));
     }
 }

src/Markdig.Tests/TestRoundtrip.cs

@@ -12,18 +12,14 @@ internal static void TestSpec(string markdownText, string expected, string exten
 
     internal static void RoundTrip(string markdown, string context = null)
     {
-        var pipelineBuilder = new MarkdownPipelineBuilder();
-        pipelineBuilder.EnableTrackTrivia();
-        pipelineBuilder.UseYamlFrontMatter();
-        MarkdownPipeline pipeline = pipelineBuilder.Build();
+        var pipeline = new MarkdownPipelineBuilder()
+            .EnableTrackTrivia()
+            .UseYamlFrontMatter()
+            .ConfigureRoundtripRenderer()
+            .Build();
         MarkdownDocument markdownDocument = Markdown.Parse(markdown, pipeline);
-        var sw = new StringWriter();
-        var nr = new RoundtripRenderer(sw);
-        pipeline.Setup(nr);
 
-        nr.Write(markdownDocument);
-
-        var result = sw.ToString();
+        var result = Markdown.ToHtml(markdownDocument, pipeline);
         TestParser.PrintAssertExpected("", result, markdown, context);
     }
 }

src/Markdig/Markdown.cs

@@ -117,7 +117,7 @@ public static string ToHtml(this MarkdownDocument document, MarkdownPipeline? pi
         pipeline ??= DefaultPipeline;
 
         using var rentedRenderer = pipeline.RentHtmlRenderer();
-        HtmlRenderer renderer = rentedRenderer.Instance;
+        var renderer = rentedRenderer.Instance;
 
         renderer.Render(document);
         renderer.Writer.Flush();
@@ -141,7 +141,7 @@ public static void ToHtml(this MarkdownDocument document, TextWriter writer, Mar
         pipeline ??= DefaultPipeline;
 
         using var rentedRenderer = pipeline.RentHtmlRenderer(writer);
-        HtmlRenderer renderer = rentedRenderer.Instance;
+        var renderer = rentedRenderer.Instance;
 
         renderer.Render(document);
         renderer.Writer.Flush();
@@ -166,7 +166,7 @@ public static MarkdownDocument ToHtml(string markdown, TextWriter writer, Markdo
         var document = MarkdownParser.Parse(markdown, pipeline, context);
 
         using var rentedRenderer = pipeline.RentHtmlRenderer(writer);
-        HtmlRenderer renderer = rentedRenderer.Instance;
+        var renderer = rentedRenderer.Instance;
 
         renderer.Render(document);
         writer.Flush();

src/Markdig/MarkdownExtensions.cs

@@ -36,6 +36,8 @@
 using Markdig.Parsers;
 using Markdig.Parsers.Inlines;
 using Markdig.Renderers;
+using Markdig.Renderers.Normalize;
+using Markdig.Renderers.Roundtrip;
 
 namespace Markdig;
 
@@ -108,7 +110,7 @@ public static MarkdownPipelineBuilder UseAlertBlocks(this MarkdownPipelineBuilde
         pipeline.Extensions.ReplaceOrAdd<AlertExtension>(new AlertExtension() { RenderKind = renderKind });
         return pipeline;
     }
-    
+
     /// <summary>
     /// Uses this extension to enable autolinks from text `http://`, `https://`, `ftp://`, `mailto:`, `www.xxx.yyy`
     /// </summary>
@@ -708,4 +710,44 @@ public static MarkdownPipelineBuilder EnableTrackTrivia(this MarkdownPipelineBui
         }
         return pipeline;
     }
+
+    /// <summary>
+    /// Configure the pipeline with a <see cref="HtmlRenderer"/>.
+    /// </summary>
+    /// <param name="pipeline">The pipeline.</param>
+    /// <param name="configureRenderer">An action which configures the <c>HtmlRenderer</c>.</param>
+    public static MarkdownPipelineBuilder ConfigureHtmlRenderer(
+        this MarkdownPipelineBuilder pipeline,
+        Func<HtmlRendererBuilder, HtmlRendererBuilder> configureRenderer)
+        => pipeline.UseRendererBuilder(configureRenderer(new HtmlRendererBuilder()));
+
+    /// <summary>
+    /// Configure the pipeline with a <see cref="NormalizeRenderer"/>.
+    /// </summary>
+    /// <param name="pipeline">The pipeline.</param>
+    /// <param name="configureRenderer">An action which configures the <c>NormalizeRenderer</c>.</param>
+    public static MarkdownPipelineBuilder ConfigureNormalizeRenderer(
+        this MarkdownPipelineBuilder pipeline,
+        Func<NormalizeRendererBuilder, NormalizeRendererBuilder> configureRenderer)
+        => pipeline.UseRendererBuilder(configureRenderer(new NormalizeRendererBuilder()));
+
+    /// <summary>
+    /// Configure the pipeline with a <see cref="RoundtripRenderer"/>.
+    /// </summary>
+    /// <param name="pipeline">The pipeline.</param>
+    public static MarkdownPipelineBuilder ConfigureRoundtripRenderer(this MarkdownPipelineBuilder pipeline)
+        => pipeline.UseRendererBuilder(new RoundtripRendererBuilder());
+
+    /// <summary>
+    /// Configure the pipeline to use a <see cref="IMarkdownRendererBuilder"/> to construct the renderer.
+    /// </summary>
+    /// <param name="pipeline">The pipeline.</param>
+    /// <param name="rendererBuilder">The builder for the renderer.</param>
+    public static MarkdownPipelineBuilder UseRendererBuilder(
+        this MarkdownPipelineBuilder pipeline,
+        IMarkdownRendererBuilder rendererBuilder)
+    {
+        pipeline.RendererBuilder = rendererBuilder;
+        return pipeline;
+    }
 }

src/Markdig/MarkdownPipeline.cs

@@ -1,5 +1,5 @@
 // Copyright (c) Alexandre Mutel. All rights reserved.
-// This file is licensed under the BSD-Clause 2 license. 
+// This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.
 
 using System.IO;
@@ -25,7 +25,8 @@ public sealed class MarkdownPipeline
         BlockParserList blockParsers,
         InlineParserList inlineParsers,
         TextWriter? debugLog,
-        ProcessDocumentDelegate? documentProcessed)
+        ProcessDocumentDelegate? documentProcessed,
+        IMarkdownRendererBuilder? rendererBuilder)
     {
         if (blockParsers is null) ThrowHelper.ArgumentNullException(nameof(blockParsers));
         if (inlineParsers is null) ThrowHelper.ArgumentNullException(nameof(inlineParsers));
@@ -35,6 +36,7 @@ public sealed class MarkdownPipeline
         InlineParsers = inlineParsers;
         DebugLog = debugLog;
         DocumentProcessed = documentProcessed;
+        RendererBuilder = rendererBuilder;
 
         SelfPipeline = Extensions.Find<SelfPipelineExtension>();
     }
@@ -57,6 +59,8 @@ public sealed class MarkdownPipeline
 
     internal SelfPipelineExtension? SelfPipeline;
 
+    internal IMarkdownRendererBuilder? RendererBuilder;
+
     /// <summary>
     /// True to parse trivia such as whitespace, extra heading characters and unescaped
     /// string values.
@@ -82,10 +86,10 @@ public void Setup(IMarkdownRenderer renderer)
     internal RentedHtmlRenderer RentHtmlRenderer(TextWriter? writer = null)
     {
         HtmlRendererCache cache = writer is null
-            ? _rendererCache ??= new HtmlRendererCache(this, customWriter: false)
-            : _rendererCacheForCustomWriter ??= new HtmlRendererCache(this, customWriter: true);
+            ? _rendererCache ??= new HtmlRendererCache(this, customWriter: false, RendererBuilder)
+            : _rendererCacheForCustomWriter ??= new HtmlRendererCache(this, customWriter: true, RendererBuilder);
 
-        HtmlRenderer renderer = cache.Get();
+        TextRendererBase renderer = cache.Get();
 
         if (writer is not null)
         {
@@ -97,22 +101,26 @@ internal RentedHtmlRenderer RentHtmlRenderer(TextWriter? writer = null)
 
     internal sealed class HtmlRendererCache(
         MarkdownPipeline pipeline,
-        bool customWriter = false) : ObjectCache<HtmlRenderer>
+        bool customWriter = false,
+        IMarkdownRendererBuilder? rendererBuilder = null) : ObjectCache<TextRendererBase>
     {
         private static readonly FastStringWriter s_dummyWriter = new();
 
         private readonly MarkdownPipeline _pipeline = pipeline;
         private readonly bool _customWriter = customWriter;
 
-        protected override HtmlRenderer NewInstance()
+        private readonly IMarkdownRendererBuilder RendererBuilder =
+            rendererBuilder ?? new HtmlRendererBuilder();
+
+        protected override TextRendererBase NewInstance()
         {
             TextWriter writer = _customWriter ? s_dummyWriter : new FastStringWriter();
-            var renderer = new HtmlRenderer(writer);
+            var renderer = RendererBuilder.Build(writer);
             _pipeline.Setup(renderer);
             return renderer;
         }
 
-        protected override void Reset(HtmlRenderer instance)
+        protected override void Reset(TextRendererBase instance)
         {
             instance.ResetInternal();
 
@@ -130,9 +138,9 @@ protected override void Reset(HtmlRenderer instance)
     internal readonly struct RentedHtmlRenderer : IDisposable
     {
         private readonly HtmlRendererCache _cache;
-        public readonly HtmlRenderer Instance;
+        public readonly TextRendererBase Instance;
 
-        internal RentedHtmlRenderer(HtmlRendererCache cache, HtmlRenderer renderer)
+        internal RentedHtmlRenderer(HtmlRendererCache cache, TextRendererBase renderer)
         {
             _cache = cache;
             Instance = renderer;

src/Markdig/MarkdownPipelineBuilder.cs

@@ -1,12 +1,13 @@
 // Copyright (c) Alexandre Mutel. All rights reserved.
-// This file is licensed under the BSD-Clause 2 license. 
+// This file is licensed under the BSD-Clause 2 license.
 // See the license.txt file in the project root for more information.
 
 using System.IO;
 
 using Markdig.Helpers;
 using Markdig.Parsers;
 using Markdig.Parsers.Inlines;
+using Markdig.Renderers;
 
 namespace Markdig;
 
@@ -89,6 +90,8 @@ public MarkdownPipelineBuilder()
 
     internal ProcessDocumentDelegate? GetDocumentProcessed => DocumentProcessed;
 
+    internal IMarkdownRendererBuilder? RendererBuilder;
+
     /// <summary>
     /// Builds a pipeline from this instance. Once the pipeline is build, it cannot be modified.
     /// </summary>
@@ -120,11 +123,12 @@ public MarkdownPipeline Build()
             new BlockParserList(BlockParsers),
             new InlineParserList(InlineParsers),
             DebugLog,
-            GetDocumentProcessed)
+            GetDocumentProcessed,
+            RendererBuilder)
         {
             PreciseSourceLocation = PreciseSourceLocation,
             TrackTrivia = TrackTrivia,
         };
         return pipeline;
     }
-}
+}

src/Markdig/Renderers/HtmlRenderer.cs

@@ -48,7 +48,7 @@ public HtmlRenderer(TextWriter writer) : base(writer)
         ObjectRenderers.Add(new EmphasisInlineRenderer());
         ObjectRenderers.Add(new LineBreakInlineRenderer());
         ObjectRenderers.Add(new HtmlInlineRenderer());
-        ObjectRenderers.Add(new HtmlEntityInlineRenderer());            
+        ObjectRenderers.Add(new HtmlEntityInlineRenderer());
         ObjectRenderers.Add(new LinkInlineRenderer());
         ObjectRenderers.Add(new LiteralInlineRenderer());
 
@@ -202,7 +202,16 @@ public HtmlRenderer WriteEscapeUrl(string? content)
             // this is the proper cross-platform way to check whether a uri is absolute or not:
             && Uri.TryCreate(content, UriKind.RelativeOrAbsolute, out var contentUri) && !contentUri.IsAbsoluteUri)
         {
-            content = new Uri(BaseUrl, contentUri).AbsoluteUri;
+            if (BaseUrl.IsAbsoluteUri)
+                content = new Uri(BaseUrl, contentUri).AbsoluteUri;
+            else
+            {
+                var baseUrl = BaseUrl.ToString();
+                content = baseUrl;
+                if (!baseUrl.EndsWith("/"))
+                    content += "/";
+                content += contentUri.ToString();
+            }
         }
 
         if (LinkRewriter != null)