/**
* @param Point $a
* @param Point $b
*
* @return Line
*/
public static function combineToRisingLine(Point $a, Point $b)
{
$minX = min($a->getX(), $b->getX());
$maxX = max($a->getX(), $b->getX());
$minY = min($a->getY(), $b->getY());
$maxY = max($a->getY(), $b->getY());
return new self(new Point($minX, $minY), new Point($maxX, $maxY));
}
/**
* @return PointSet
*/
public function produce()
{
/*
* Bressenham's Midpoint Circle algorithm
* http://stackoverflow.com/questions/1022178/how-to-make-a-circle-on-a-grid
* http://rosettacode.org/wiki/Bitmap/Midpoint_circle_algorithm
*/
$d = 3 - 2 * $this->radius;
$x = 0;
$y = $this->radius;
$result = new PointSet();
do {
$this->addRow($result, new Point($this->center->getX() + $x, $this->center->getY() + $y), new Point($this->center->getX() - $x, $this->center->getY() + $y));
$this->addRow($result, new Point($this->center->getX() - $x, $this->center->getY() - $y), new Point($this->center->getX() + $x, $this->center->getY() - $y));
$this->addRow($result, new Point($this->center->getX() - $y, $this->center->getY() + $x), new Point($this->center->getX() + $y, $this->center->getY() + $x));
$this->addRow($result, new Point($this->center->getX() - $y, $this->center->getY() - $x), new Point($this->center->getX() + $y, $this->center->getY() - $x));
if ($d < 0) {
$d = $d + 4 * $x + 6;
} else {
$d = $d + 4 * ($x - $y) + 10;
--$y;
}
++$x;
} while ($x <= $y);
return $result;
}
/**
* @param Point $a
* @param Point $b
*
* @return LinearFunction
*
* @throws \RuntimeException When $a and $b points have same x
*/
public static function fromTwoPoints(Point $a, Point $b)
{
if ($a->getX() === $b->getX()) {
throw new \RuntimeException('Line can be defined only by two points with different X');
}
$k = ($a->getY() - $b->getY()) / ($a->getX() - $b->getX());
$n = $a->getY() - $k * $a->getX();
return new self($k, $n);
}
