public function getRulers($line = 10)
{
if ($line == 0) {
return [];
}
$data = [0];
$percent = $this->panel->duration / 100;
$row = $this->panel->duration / $line;
$precision = $row > 100 ? -2 : -1;
for ($i = 1; $i < $line; $i++) {
$ms = round($i * $row, $precision);
$data[$ms] = $ms / $percent;
}
return $data;
}