protected function calculateDisplayRange()
{
$maximumNumberOfLinks = $this->maximumNumberOfLinks;
if ($maximumNumberOfLinks > $this->numberOfPages) {
$maximumNumberOfLinks = $this->numberOfPages;
}
$delta = floor($maximumNumberOfLinks / 2);
$this->displayRangeStart = $this->currentPage - $delta;
$this->displayRangeEnd = $this->currentPage + $delta + ($maximumNumberOfLinks % 2 === 0 ? 1 : 0);
if ($this->displayRangeStart < 1) {
$this->displayRangeEnd -= $this->displayRangeStart - 1;
}
if ($this->displayRangeEnd > $this->numberOfPages) {
$this->displayRangeStart -= $this->displayRangeEnd - $this->numberOfPages;
}
$this->displayRangeStart = (int) max($this->displayRangeStart, 1);
$this->displayRangeEnd = (int) min($this->displayRangeEnd, $this->numberOfPages);
}