Fix composite glyph output (#581)

* Fix composite glyph output * Pad zeros before checksum calulation --------- Co-authored-by: Nicola Asuni <nicolaasuni@users.noreply.github.com>
tecnickcom · Sep 6, 2023 · 7e3fb6f · 7e3fb6f
1 parent de332db
commit 7e3fb6f
Showing 1 changed file with 22 additions and 22 deletions.
diff --git a/include/tcpdf_fonts.php b/include/tcpdf_fonts.php
@@ -1323,43 +1323,43 @@ public static function _getTrueTypeFontSubset($font, $subsetchars) {
 					// set the checkSumAdjustment to 0
 					$table[$tag]['data'] = substr($table[$tag]['data'], 0, 8)."\x0\x0\x0\x0".substr($table[$tag]['data'], 12);
 				}
-				$pad = 4 - ($table[$tag]['length'] % 4);
-				if ($pad != 4) {
-					// the length of a table must be a multiple of four bytes
-					$table[$tag]['length'] += $pad;
-					$table[$tag]['data'] .= str_repeat("\x0", $pad);
-				}
 				$table[$tag]['offset'] = $offset;
 				$offset += $table[$tag]['length'];
+				$numPad = ($offset + 3 & ~3) - $offset;
+				if($numPad > 0) {
+					$table[$tag]['data'] .= str_repeat("\x0", $numPad);
+					$offset += $numPad;
+				}
 				// check sum is not changed (so keep the following line commented)
-				//$table[$tag]['checkSum'] = self::_getTTFtableChecksum($table[$tag]['data'], $table[$tag]['length']);
+				//$table[$tag]['checkSum'] = self::_getTTFtableChecksum($table[$tag]['data'], $table[$tag]['length'] + $numPad);
 			} else {
 				unset($table[$tag]);
 			}
 		}
 		// add loca
+		$table['loca'] = array();
 		$table['loca']['data'] = $loca;
 		$table['loca']['length'] = strlen($loca);
-		$pad = 4 - ($table['loca']['length'] % 4);
-		if ($pad != 4) {
-			// the length of a table must be a multiple of four bytes
-			$table['loca']['length'] += $pad;
-			$table['loca']['data'] .= str_repeat("\x0", $pad);
-		}
 		$table['loca']['offset'] = $offset;
-		$table['loca']['checkSum'] = self::_getTTFtableChecksum($table['loca']['data'], $table['loca']['length']);
 		$offset += $table['loca']['length'];
+		$numPad = ($offset + 3 & ~3) - $offset;
+		if($numPad > 0) {
+			$table['loca']['data'] .= str_repeat("\x0", $numPad);
+			$offset += $numPad;
+		}
+		$table['loca']['checkSum'] = self::_getTTFtableChecksum($table['loca']['data'], $table['loca']['length'] + $numPad);
 		// add glyf
+		$table['glyf'] = array();
 		$table['glyf']['data'] = $glyf;
 		$table['glyf']['length'] = strlen($glyf);
-		$pad = 4 - ($table['glyf']['length'] % 4);
-		if ($pad != 4) {
-			// the length of a table must be a multiple of four bytes
-			$table['glyf']['length'] += $pad;
-			$table['glyf']['data'] .= str_repeat("\x0", $pad);
-		}
 		$table['glyf']['offset'] = $offset;
-		$table['glyf']['checkSum'] = self::_getTTFtableChecksum($table['glyf']['data'], $table['glyf']['length']);
+		$offset += $table['glyf']['length'];
+		$numPad = ($offset + 3 & ~3) - $offset;
+		if($numPad > 0) {
+			$table['glyf']['data'] .= str_repeat("\x0", $numPad);
+			$offset += $numPad;
+		}
+		$table['glyf']['checkSum'] = self::_getTTFtableChecksum($table['glyf']['data'], $table['glyf']['length'] + $numPad);
 		// rebuild font
 		$font = '';
 		$font .= pack('N', 0x10000); // sfnt version
@@ -1383,7 +1383,7 @@ public static function _getTrueTypeFontSubset($font, $subsetchars) {
 		}
 		// set checkSumAdjustment on head table
 		$checkSumAdjustment = 0xB1B0AFBA - self::_getTTFtableChecksum($font, strlen($font));
-		$font = substr($font, 0, $table['head']['offset'] + 8).pack('N', $checkSumAdjustment).substr($font, $table['head']['offset'] + 12);
+		$font = substr($font, 0, $table['head']['offset'] + $offset + 8).pack('N', $checkSumAdjustment).substr($font, $table['head']['offset'] + $offset + 12);
 		return $font;
 	}