private function splitStringByWidth($string, $width)
{
// str_split is not suitable for multi-byte characters, we should use preg_split to get char array properly.
// additionally, array_slice() is not enough as some character has doubled width.
// we need a function to split string not by character count but by string width
if (false === ($encoding = mb_detect_encoding($string, null, true))) {
return str_split($string, $width);
}
$utf8String = mb_convert_encoding($string, 'utf8', $encoding);
$lines = array();
$line = '';
foreach (preg_split('//u', $utf8String) as $char) {
// test if $char could be appended to current line
if (mb_strwidth($line . $char, 'utf8') <= $width) {
$line .= $char;
continue;
}
// if not, push current line to array and make new line
$lines[] = str_pad($line, $width);
$line = $char;
}
if ('' !== $line) {
$lines[] = count($lines) ? str_pad($line, $width) : $line;
}
mb_convert_variables($encoding, 'utf8', $lines);
return $lines;
}