function resize($width, $height, $flags = self::FIT)
{
if ($this->file === NULL) {
return parent::resize($width, $height, $flags);
}
$mirror = '';
if ($width < 0) {
$mirror .= ' -flop';
}
if ($height < 0) {
$mirror .= ' -flip';
}
list($newWidth, $newHeight) = self::calculateSize($this->getWidth(), $this->getHeight(), $width, $height, $flags);
$this->execute("convert -resize {$newWidth}x{$newHeight}! {$mirror} -strip %input %output", self::PNG);
return $this;
}
