Steven

WP-Syntax provides clean syntax highlighting using 
<a href="http://qbnz.com/highlighter/" rel="nofollow ugc">GeSHi</a> — supporting a wide range of popular 
languages. It supports highlighting with or without line numbers and maintains formatting while copying snippets of code 
from the browser.
It avoids conflicts with other 3rd party plugins by running an early 
pre-filter and a late post-filter that substitutes and pulls the code snippets 
out first and then pushes them back in with highlighting at the end. The 
result is source code formatted and highlighted the way you intended.
Usage, Supported Languages, Styling Guidelines, and Release Notes are available 
in the <a href="https://wordpress.org/extend/plugins/wp-syntax/other_notes/" rel="ugc">Other Notes</a> section.
Want to contribute? WP-Syntax can be found on GitHub. <a href="https://github.com/shazahm1/WP-Syntax" rel="nofollow ugc">Fork and submit your pull requests today!</a>
<h4>Basic Usage</h4>
Wrap code blocks with <code><pre lang="LANGUAGE" line="1"></code> and <code></pre></code> where “LANGUAGE” 
is a <a href="http://qbnz.com/highlighter/" rel="nofollow ugc">GeSHi</a> supported language syntax. 
The <code>line</code> attribute is optional. <a href="https://wordpress.org/extend/plugins/wp-syntax/other_notes/" rel="ugc">More usage examples</a>
<h3>Usage</h3>
Wrap code blocks with <code><pre lang="LANGUAGE" line="1"></code> and <code></pre></code> where “LANGUAGE” is a <a href="http://qbnz.com/highlighter/" rel="nofollow ugc">GeSHi</a> supported 
language syntax. See below for a full list of supported languages. 
The <code>line</code> attribute is optional.
Example 1: PHP, no line numbers
<pre><code><pre lang="php">
<div id="foo">
<?php
 function foo() {
 echo "Hello World!\\n";
 }
?>
</div>
</pre>
</code></pre>
Example 2: Java, with line numbers
<pre><code><pre lang="java" line="1">
public class Hello {
 public static void main(String[] args) {
 System.out.println("Hello World!");
 }
}
</pre>
</code></pre>
Example 3: Ruby, with line numbers starting at 18
<pre><code><pre lang="ruby" line="18">
class Example
 def example(arg1)
 return "Hello: " + arg1.to_s
 end
end
</pre>
</code></pre>
Example 4: If your code already has html entities escaped, use <code>escaped="true"</code> as an option
<pre><code><pre lang="xml" escaped="true">
&lt;xml&gt;Hello&lt;/xml&gt;
</pre>
</code></pre>
Example 5: PHP, with line numbers and highlighting a specific line
<pre><code><pre lang="php" line="1" highlight="3">
<div id="foo">
<?php
 function foo() {
 echo "Hello World!\\n";
 }
?>
</div>
</pre>
</code></pre>
Example 6: PHP, with a caption (file and/or file path of the source file)
<pre><code><pre lang="php" src"https://github.com/shazahm1/Connections/blob/master/connections.php">
<div id="foo">
<?php
 function foo() {
 echo "Hello World!\\n";
 }
?>
</div>
</pre><h3>Supported Languages</h3>
</code></pre>
The following languages are most supported in the <code>lang</code> attribute:
abap, actionscript, actionscript3, ada, apache, applescript, apt_sources, asm, 
asp, autoit, avisynth, bash, bf, bibtex, blitzbasic, bnf, boo, c, 
c_mac, caddcl, cadlisp, cil, cfdg, cfm, cmake, cobol, cpp-qt, cpp, 
csharp, css, d, dcs, delphi, diff, div, dos, dot, eiffel, email, erlang, 
fo, fortran, freebasic, genero, gettext, glsl, gml, bnuplot, groovy, haskell, 
hq9plus, html4strict, idl, ini, inno, intercal, io, java, java5, 
javascript, kixtart, klonec, klonecpp, latex, lisp, locobasic, lolcode 
lotusformulas, lotusscript, lscript, lsl2, lua, m68k, make, matlab, mirc, 
modula3, mpasm, mxml, mysql, nsis, oberon2, objc, ocaml-brief, ocaml, 
oobas, oracle11, oracle8, pascal, per, pic16, pixelbender, perl, 
php-brief, php, plsql, povray, powershell, progress, prolog, properties, 
providex, python, qbasic, rails, rebol, reg, robots, ruby, sas, 
scala, scheme, scilab, sdlbasic, smalltalk, smarty, sql, tcl, teraterm, 
text, thinbasic, tsql, typoscript, vb, vbnet, verilog, vhdl, vim, 
visualfoxpro, visualprolog, whitespace, whois, winbatch, xml, xorg_conf, 
xpp, z80
See the <a href="http://qbnz.com/highlighter/geshi-doc.html" rel="nofollow ugc">GeSHi Documentation</a> 
for a full list of supported languages.
(Bold languages just highlight the more popular ones.)
<h3>Styling Guidelines</h3>
WP-Syntax colors code using the default GeSHi colors. It also uses inline 
styling to make sure that code highlights still work in RSS feeds. It uses a 
default <code>wp-syntax.css</code> stylesheet for basic layout. To customize your styling, 
copy the default <code>wp-content/plugins/wp-syntax/wp-syntax.css</code> to your theme’s 
template directory and modify it. If a file named <code>wp-syntax.css</code> exists in 
your theme’s template directory, this stylesheet is used instead of the default. 
This allows theme authors to add their own customizations as they see fit.
<h3>Advanced Customization</h3>
WP-Syntax supports a <code>wp_syntax_init_geshi</code> action hook to customize GeSHi 
initialization settings. Blog owners can handle the hook in a hand-made plugin 
or somewhere else like this:
<pre><code><?php
add_action('wp_syntax_init_geshi', 'my_custom_geshi_styles');

function my_custom_geshi_styles(&$geshi)
{
 $geshi->set_brackets_style('color: #000;');
 $geshi->set_keyword_group_style(1, 'color: #22f;');
}
?>
</code></pre>
This allows for a great possibility of different customizations. Be sure to 
review the <a href="http://qbnz.com/highlighter/geshi-doc.html" rel="nofollow ugc">GeSHi Documentation</a>.

WP-Syntax

WP-Syntax provides clean syntax highlighting for embedding source code within pages or posts.

wakalab

Markdown Renderer for GitHub transforms your WordPress content with beautiful GitHub Flavored Markdown (GFM) rendering. Perfect for technical blogs, documentation sites, and any content that needs professional code presentation.
Key Features:
🎨 Beautiful Syntax Highlighting 
* Powered by Shiki – the same syntax highlighter used by VS Code 
* Support for 100+ programming languages 
* Multiple beautiful themes (GitHub Light/Dark, VS Code themes, and more) 
* Automatic language detection
📊 Mermaid Diagram Support 
* Create flowcharts, sequence diagrams, and more 
* Professional diagram rendering 
* Interactive zoom functionality 
* Error handling with user-friendly messages
📈 Chart.js Chart Support 
* Create line, bar, pie, doughnut, and more chart types 
* 8 chart types including scatter, bubble, radar, and Polar Area 
* Simple JSON configuration in “`chart fenced code blocks 
* Responsive and interactive charts
✨ GitHub Flavored Markdown 
* Tables, task lists, strikethrough 
* Automatic URL linking 
* Footnotes support 
* 100% compatible with GitHub markdown
📋 Copy Button Feature 
* One-click code copying 
* GitHub-style user experience 
* Full accessibility support 
* Mobile-friendly design
⚡ Performance Optimized 
* Asset lazy loading 
* Minimal performance impact 
* CDN-friendly architecture 
* Optimized for WordPress
🌍 Developer Friendly 
* Clean, semantic HTML output 
* Extensive hooks and filters 
* Translation ready (i18n) 
* WordPress coding standards
Perfect for: 
* Technical blogs and tutorials 
* Documentation websites 
* Code portfolios 
* Educational content 
* API documentation 
* Developer resources
<h3>Technical Requirements</h3>
<ul>
<li>WordPress 6.5 or higher</li>
<li>PHP 8.2 or higher</li>
<li>Modern browser with JavaScript enabled</li>
<li>Recommended: 128MB+ PHP memory limit</li>
</ul>
<h3>Support</h3>
For support, please visit the WordPress.org support forum for this plugin. Our team actively monitors and responds to support requests.
Before posting a support request: 
* Check the FAQ section above for common questions 
* Ensure you’re using the latest version of the plugin 
* Include your WordPress and PHP versions in your support request
Feature Requests: 
We welcome feature suggestions! Please post them in the support forum with detailed descriptions of your use case.
<h3>Source Code</h3>
This plugin uses build tools for development efficiency.
Compressed File Source Code: 
* build/index.js: WordPress Block Editor integration code 
 * Source: blocks/markdown/src/ folder 
 * Build: npm run build
Source Code Access: 
* GitHub Repository: https://github.com/wakalab/markdown-renderer-for-github 
* License: GPL v2 or later 
* Development Branch: main
Build Instructions: 
1. Install Node.js 18+ 
2. Install dependencies with <code>npm install</code> 
3. Build with <code>npm run build</code> 
4. Run tests with <code>npm run test</code>
Developer Resources: 
* Development Environment Setup: See CLAUDE.md and docs/DEVELOPMENT.md 
* Contributing: See CONTRIBUTING.md 
* Build Process Details: See BUILD.md
<h3>Third Party Services</h3>
This plugin operates entirely self-contained and does NOT use any external third-party services.
Complete Local Operation: 
* All JavaScript libraries are bundled locally within the plugin 
* Shiki syntax highlighter – served from your WordPress installation (no CDN) 
* Mermaid diagram renderer – served from your WordPress installation (no CDN) 
* Chart.js chart renderer – served from your WordPress installation (no CDN) 
* No external API calls or network requests are made
Privacy & Security Benefits: 
* No data is transmitted to external servers 
* No tracking, analytics, or data collection 
* No external dependencies that could compromise your site 
* GDPR compliant by design 
* Works offline and in closed networks
All functionality is fully self-contained within your WordPress installation with no external service dependencies.
<h3>Privacy</h3>
This plugin does not collect any personal data. All processing is done locally on your server.
<h3>Credits</h3>
<ul>
<li>Syntax highlighting: <a href="https://shiki.style/" rel="nofollow ugc">Shiki</a></li>
<li>Diagram rendering: <a href="https://mermaid.js.org/" rel="nofollow ugc">Mermaid</a></li>
<li>Chart rendering: <a href="https://www.chartjs.org/" rel="nofollow ugc">Chart.js</a></li>
<li>Markdown parsing: <a href="https://markdown-it.github.io/" rel="nofollow ugc">markdown-it</a></li>
</ul>
<h3>Developer Information</h3>
This section provides essential information for developers who want to extend or customize the plugin.
For complete API documentation, architecture diagrams, and customization examples, see: 
<a href="https://github.com/wakalab/markdown-renderer-for-github/tree/main/docs" rel="nofollow ugc">Developer Documentation on GitHub</a>
<h4>Available Hooks and Filters</h4>
Actions:
<ul>
<li><code>gfmr_metadata_saved</code> – Fired when code block metadata is saved
<ul>
<li>Parameters: <code>$post_id</code> (int), <code>$metadata</code> (array)</li>
<li>Use case: Sync metadata with external services, logging</li>
</ul>
</li>
</ul>
Filters:
<ul>
<li>
<code>gfmr_metadata_get_metadata</code> – Filter retrieved metadata before use
<ul>
<li>Parameters: <code>$metadata</code> (array), <code>$post_id</code> (int)</li>
<li>Use case: Custom language detection, metadata modification</li>
</ul>
</li>
<li>
<code>gfmr_schema_data</code> – Filter Schema.org JSON-LD data before output
<ul>
<li>Parameters: <code>$schema</code> (array), <code>$post</code> (WP_Post)</li>
<li>Use case: Add custom schema properties, author profiles</li>
</ul>
</li>
</ul>
<h4>PHP Constants</h4>
<ul>
<li><code>GFMR_PLUGIN_FILE</code> – Plugin main file path</li>
<li><code>GFMR_SLUG</code> – Plugin slug (‘markdown-renderer-for-github’)</li>
<li><code>GFMR_URI</code> – Plugin URL</li>
<li><code>GFMR_PATH</code> – Plugin directory path</li>
<li><code>GFMR_PLUGIN_PATH</code> – Plugin directory name (relative)</li>
<li><code>GFMR_PLUGIN_BASENAME</code> – Plugin basename</li>
<li><code>GFMR_ASSETS_PATH</code> – Assets directory URL</li>
</ul>
<h4>JavaScript Global Objects</h4>
<ul>
<li><code>wpGfmConfig</code> – Plugin configuration object</li>
<li><code>wpGfmRenderer</code> – Core rendering API (processCodeBlocks, renderContent, initialize)</li>
<li><code>wpGfmHighlighter</code> – Highlighter wrapper instance</li>
<li><code>wpGfmShikiHighlighter</code> – Actual Shiki highlighter instance</li>
<li><code>wpGfmUnifiedHighlight(code, lang, options)</code> – Unified highlight function</li>
<li><code>wpGfmSwitchTheme(newTheme)</code> – Theme switching function (‘light’, ‘dark’, ‘system’)</li>
<li><code>wpGfmRenderDiagram(content, element, options)</code> – Diagram rendering function</li>
</ul>
<h4>Settings Option</h4>
Option name: <code>gfmr_theme_settings</code>
Available keys:
<ul>
<li><code>theme</code> – Theme setting (‘light’, ‘dark’, ‘system’)</li>
<li><code>schema_enabled</code> – Enable Schema.org JSON-LD output (bool)</li>
<li><code>schema_auto_detect_type</code> – Auto-detect article type (bool)</li>
<li><code>schema_include_author</code> – Include author in schema (bool)</li>
<li><code>schema_include_publisher</code> – Include publisher in schema (bool)</li>
</ul>
<h4>Plugin Development</h4>
This plugin follows WordPress coding standards and provides clean, semantic HTML output.
Detailed Documentation:
For complete documentation including full API reference with code examples, architecture diagrams (Mermaid), step-by-step customization guides, and CSS class reference, visit:
<a href="https://github.com/wakalab/markdown-renderer-for-github/tree/main/docs" rel="nofollow ugc">GitHub Developer Documentation</a>

Markdown Renderer for GitHub

Transform your WordPress content with beautiful GitHub Flavored Markdown rendering, syntax highlighting, interactive diagrams, and Chart.js charts.

WP-Syntax vs Markdown Renderer for GitHub