Multi-byte character support for filename during output (#561). (#562)

Co-authored-by: Nicola Asuni <nicolaasuni@users.noreply.github.com>

tcpdf.php

@@ -7616,7 +7616,7 @@ public function setAbsXY($x, $y) {
 	 * Send the document to a given destination: string, local file or browser.
 	 * In the last case, the plug-in may be used (if present) or a download ("Save as" dialog box) may be forced.<br />
 	 * The method first calls Close() if necessary to terminate the document.
-	 * @param string $name The name of the file when saved. Note that special characters are removed and blanks characters are replaced with the underscore character.
+	 * @param string $name The name of the file when saved
 	 * @param string $dest Destination where to send the document. It can take one of the following values:<ul><li>I: send the file inline to the browser (default). The plug-in is used if available. The name given by name is used when one selects the "Save as" option on the link generating the PDF.</li><li>D: send to the browser and force a file download with the name given by name.</li><li>F: save to a local server file with the name given by name.</li><li>S: return the document as a string (name is ignored).</li><li>FI: equivalent to F + I option</li><li>FD: equivalent to F + D option</li><li>E: return the document as base64 mime multi-part email attachment (RFC 2045)</li></ul>
 	 * @return string
 	 * @public
@@ -7634,10 +7634,7 @@ public function Output($name='doc.pdf', $dest='I') {
 			$dest = $dest ? 'D' : 'F';
 		}
 		$dest = strtoupper($dest);
-		if ($dest[0] != 'F' && $name !== null) {
-			$name = preg_replace('/[\s]+/', '_', $name);
-			$name = preg_replace('/[^a-zA-Z0-9_\.-]/', '', $name);
-		}
+
 		if ($this->sign) {
 			// *** apply digital signature to the document ***
 			// get the document content
@@ -7708,7 +7705,8 @@ public function Output($name='doc.pdf', $dest='I') {
 					header('Pragma: public');
 					header('Expires: Sat, 26 Jul 1997 05:00:00 GMT'); // Date in the past
 					header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');
-					header('Content-Disposition: inline; filename="'.basename($name).'"');
+					header('Content-Disposition: inline; filename="' . rawurlencode(basename($name)) . '"; ' .
+						'filename*=UTF-8\'\'' . rawurlencode(basename($name)));
 					TCPDF_STATIC::sendOutputData($this->getBuffer(), $this->bufferlen);
 				} else {
 					echo $this->getBuffer();
@@ -7739,7 +7737,8 @@ public function Output($name='doc.pdf', $dest='I') {
 					header('Content-Type: application/pdf');
 				}
 				// use the Content-Disposition header to supply a recommended filename
-				header('Content-Disposition: attachment; filename="'.basename($name).'"');
+				header('Content-Disposition: attachment; filename="' . rawurlencode(basename($name)) . '"; ' .
+					'filename*=UTF-8\'\'' . rawurlencode(basename($name)));
 				header('Content-Transfer-Encoding: binary');
 				TCPDF_STATIC::sendOutputData($this->getBuffer(), $this->bufferlen);
 				break;