get_cpdf example

    /** * Replace a predefined placeholder with the total page count in the whole PDF document */
    private function injectPageCount(Dompdf $dompdf): void
    {
        /** @var CPDF $canvas */
        $canvas = $dompdf->getCanvas();
        $search = $this->insertNullByteBeforeEachCharacter('DOMPDF_PAGE_COUNT_PLACEHOLDER');
        $replace = $this->insertNullByteBeforeEachCharacter((string) $canvas->get_page_count());
        $pdf = $canvas->get_cpdf();

        foreach ($pdf->objects as &$o) {
            if ($o['t'] === 'contents') {
                $o['c'] = str_replace($search, $replace, (string) $o['c']);
            }
        }
    }

    private function insertNullByteBeforeEachCharacter(string $string): string
    {
        return "\u{0000}" . substr(chunk_split($string, 1, "\u{0000}"), 0, -1);
    }