Pdf Writer strtoupper() fix (#1629)

* _setPageSize's strtoupper()  on array argument

PhpSpreadsheet/Writer/Pdf.php Class defines a protected static mixed array called $paperSizes, this array contains string values along with array values. 'strtoupper() expects parameter 1 to be string, array given' error happens due to array passed to $paperSize variable from that $paperSizes mixed array on the Mpdf Class where Pdf extends

Examples of cases, when a 'Letter' paper size is chosen, then no problem occurs since the index in that value for the array is a string value, but when 'Tabloid' paper size is chosen the value in the index for that paper size is an array, that's when the strtoupper() error happens

* _setPageSize's strtoupper() on array argument

PhpSpreadsheet/Writer/Pdf.php Class defines a protected static mixed array called $paperSizes, this array contains string values along with array values. 'strtoupper() expects parameter 1 to be string, array given' error happens due to array passed to $paperSize variable from that $paperSizes mixed array on the Dompdf Class where Pdf extends

Examples of cases; when a 'Letter' paper size is chosen, then no problem occurs since the index in the array for that value a string, but when 'Tabloid' paper size is chosen the value in the index for that paper size is an array, that's when the strtoupper() error happens.

src/PhpSpreadsheet/Writer/Pdf/Dompdf.php

@@ -59,7 +59,7 @@ public function save($pFilename): void
 
         //  Create PDF
         $pdf = $this->createExternalWriterInstance();
-        $pdf->setPaper(strtolower($paperSize), $orientation);
+        $pdf->setPaper($paperSize, $orientation);
 
         $pdf->loadHtml($this->generateHTMLAll());
         $pdf->render();

src/PhpSpreadsheet/Writer/Pdf/Mpdf.php

@@ -64,7 +64,7 @@ public function save($pFilename): void
         $config = ['tempDir' => $this->tempDir . '/mpdf'];
         $pdf = $this->createExternalWriterInstance($config);
         $ortmp = $orientation;
-        $pdf->_setPageSize(strtoupper($paperSize), $ortmp);
+        $pdf->_setPageSize($paperSize, $ortmp);
         $pdf->DefOrientation = $orientation;
         $pdf->AddPageByArray([
             'orientation' => $orientation,