From fdff760615b4b15073c110063adabe9954f4f460 Mon Sep 17 00:00:00 2001
From: Faisal Ahammad <faisalahammad24@gmail.com>
Date: Sun, 2 Aug 2026 14:24:35 +0600
Subject: [PATCH] Add max-height setting for code blocks

Adds a global "Max Height" setting to the SyntaxHighlighter settings
page. When set (in pixels), code blocks get a max-height with a vertical
scrollbar so long code no longer stretches the page.

Setting is off by default (0). Applies to both shortcode and Gutenberg
block output. No build step needed (PHP only).

Fixes #282
---
 syntaxhighlighter.php | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/syntaxhighlighter.php b/syntaxhighlighter.php
index ee3b9d0..823cece 100644
--- a/syntaxhighlighter.php
+++ b/syntaxhighlighter.php
@@ -101,6 +101,7 @@ function_exists( 'parse_blocks' ) // WordPress 5.0+
 			'collapse'       => 0,
 			'firstline'      => 1,
 			'gutter'         => 1,
+			'maxheight'      => 0, // 0 disables the max-height cap
 			'htmlscript'     => 0,
 			'light'          => 0,
 			'padlinenumbers' => 'false',
@@ -1138,6 +1139,14 @@ function maybe_output_scripts() {
 			echo "	SyntaxHighlighter.defaults['quick-code'] = false;\n";
 		}
 
+		if ( ! empty( $this->settings['maxheight'] ) ) {
+			$maxheight = (int) $this->settings['maxheight'];
+			echo "	var maxheightcss = document.createElement( 'style' );\n";
+			echo "	maxheightcss.setAttribute( 'type', 'text/css' );\n";
+			echo "	maxheightcss.appendChild( document.createTextNode( '" . esc_attr( ".syntaxhighlighter { max-height: {$maxheight}px !important; overflow-y: auto !important; }" ) . "' ) );\n";
+			echo "	document.head.appendChild( maxheightcss );\n";
+		}
+
 ?>	SyntaxHighlighter.all();
 
 	// Infinite scroll support
@@ -1490,6 +1499,14 @@ function settings_page() { ?>
 				</fieldset>
 			</td>
 		</tr>
+		<tr valign="top">
+			<th scope="row"><label for="syntaxhighlighter-maxheight"><?php esc_html_e( 'Max Height (in pixels)', 'syntaxhighlighter' ); ?></label></th>
+			<td>
+				<input name="syntaxhighlighter_settings[maxheight]" type="text" id="syntaxhighlighter-maxheight" value="<?php echo esc_attr( $this->settings['maxheight'] ); ?>" class="small-text" />
+				<br />
+				<?php esc_html_e( 'The maximum height of a code block before a vertical scrollbar appears. Set to 0 to disable.', 'syntaxhighlighter' ); ?>
+			</td>
+		</tr>
 	</table>
 
 	<h3><?php esc_html_e( 'Defaults', 'syntaxhighlighter' ); ?></h3>
@@ -1811,6 +1828,7 @@ function validate_settings( $settings ) {
 			$settings['classname']      = ( ! empty( $settings['classname'] ) ) ? preg_replace( '/[^ A-Za-z0-9_-]*/', '', $settings['classname'] ) : '';
 			$settings['firstline']      = (int) ( ( ! empty( $settings['firstline'] ) ) ? $settings['firstline'] : $this->defaultsettings['firstline'] );
 			$settings['tabsize']        = (int) ( ( ! empty( $settings['tabsize'] ) ) ? $settings['tabsize'] : $this->defaultsettings['tabsize'] );
+			$settings['maxheight']       = (int) max( 0, ( $settings['maxheight'] ?? $this->defaultsettings['maxheight'] ) );
 		}
 
 		return $settings;