From f0972cf0569c644fb57a8675764eddd85cbb77a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jindra=20Pet=C5=99=C3=ADk?= <jindra.petrik@gmail.com>
Date: Mon, 2 Feb 2026 09:58:58 +0100
Subject: [PATCH] Fixed: Font subsetting - incorrect placement of head checksum
 overwriting head offset.

---
 include/tcpdf_fonts.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/tcpdf_fonts.php b/include/tcpdf_fonts.php
index fbe7009c..fc75e0f2 100644
--- a/include/tcpdf_fonts.php
+++ b/include/tcpdf_fonts.php
@@ -1384,7 +1384,7 @@ public static function _getTrueTypeFontSubset($font, $subsetchars) {
 		}
 		// set checkSumAdjustment on head table
 		$checkSumAdjustment = 0xB1B0AFBA - self::_getTTFtableChecksum($font, strlen($font));
-		$font = substr($font, 0, $table['head']['offset'] + $offset + 8).pack('N', $checkSumAdjustment).substr($font, $table['head']['offset'] + $offset + 12);
+		$font = substr($font, 0, $table['head']['offset'] + $offset + 4).pack('N', $checkSumAdjustment).substr($font, $table['head']['offset'] + $offset + 8);
 		return $font;
 	}