PHP 5용 WebP 크기 추출 함수

function getWebPSize($filename) {

    $fp = fopen($filename, 'rb');

    if (!$fp) {

        return false;

    }

    $header = fread($fp, 30);

    fclose($fp);

    if (substr($header, 0, 4) !== "RIFF" || substr($header, 8, 4) !== "WEBP") {

        return false;

    }

    $chunk_type = substr($header, 12, 4);

    if ($chunk_type === "VP8 ") {

        // Lossy WebP

        $w = unpack("v", substr($header, 26, 2));

        $h = unpack("v", substr($header, 28, 2));

        $width  = $w[1] & 0x3FFF;

        $height = $h[1] & 0x3FFF;

        return array($width, $height);

    } elseif ($chunk_type === "VP8X") {

        // Extended WebP

        $w = unpack("C3", substr($header, 24, 3));

        $h = unpack("C3", substr($header, 27, 3));

        $width  = ($w[1] | ($w[2] << 8) | ($w[3] << 16)) + 1;

        $height = ($h[1] | ($h[2] << 8) | ($h[3] << 16)) + 1;

        return array($width, $height);

    }

    return false;

}

// 예제 사용

$size = getWebPSize('example.webp');

if ($size !== false) {

    echo 'Width: ' . $size[0] . ', Height: ' . $size[1];

} else {

    echo 'WebP 이미지가 아니거나 읽기 실패.';

}

?>