Mega Code Archive
Returns distance to segment
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import java.awt.Point;
public class Util{
/**
* Returns distance to segment
*
* @param ss
* segment start point
* @param se
* segment end point
* @param p
* point to found closest point on segment
* @return distance to segment
*/
public static double getDistanceToSegment(Point ss, Point se, Point p)
{
return getDistanceToSegment(ss.x, ss.y, se.x, se.y, p.x, p.y);
}
/**
* Returns distance to segment
*
* @param sx1
* segment x coord 1
* @param sy1
* segment y coord 1
* @param sx2
* segment x coord 2
* @param sy2
* segment y coord 2
* @param px
* point x coord
* @param py
* point y coord
* @return distance to segment
*/
public static double getDistanceToSegment(int sx1, int sy1, int sx2, int sy2, int px, int py)
{
Point closestPoint = getClosestPointOnSegment(sx1, sy1, sx2, sy2, px, py);
return getDistance(closestPoint.x, closestPoint.y, px, py);
}
/**
* Returns distance between two 2D points
*
* @param point1
* first point
* @param point2
* second point
* @return distance between points
*/
public static double getDistance(Point point1, Point point2)
{
return getDistance(point1.x, point1.y, point2.x, point2.y);
}
/**
* Returns distance between two sets of coords
*
* @param x1
* first x coord
* @param y1
* first y coord
* @param x2
* second x coord
* @param y2
* second y coord
* @return distance between sets of coords
*/
public static double getDistance(float x1, float y1, float x2, float y2)
{
// using long to avoid possible overflows when multiplying
double dx = x2 - x1;
double dy = y2 - y1;
// return Math.hypot(x2 - x1, y2 - y1); // Extremely slow
// return Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)); // 20 times faster than hypot
return Math.sqrt(dx * dx + dy * dy); // 10 times faster then previous line
}
/**
* Returns closest point on segment to point
*
* @param ss
* segment start point
* @param se
* segment end point
* @param p
* point to found closest point on segment
* @return closest point on segment to p
*/
public static Point getClosestPointOnSegment(Point ss, Point se, Point p)
{
return getClosestPointOnSegment(ss.x, ss.y, se.x, se.y, p.x, p.y);
}
/**
* Returns closest point on segment to point
*
* @param sx1
* segment x coord 1
* @param sy1
* segment y coord 1
* @param sx2
* segment x coord 2
* @param sy2
* segment y coord 2
* @param px
* point x coord
* @param py
* point y coord
* @return closets point on segment to point
*/
public static Point getClosestPointOnSegment(int sx1, int sy1, int sx2, int sy2, int px, int py)
{
double xDelta = sx2 - sx1;
double yDelta = sy2 - sy1;
if ((xDelta == 0) && (yDelta == 0))
{
throw new IllegalArgumentException("Segment start equals segment end");
}
double u = ((px - sx1) * xDelta + (py - sy1) * yDelta) / (xDelta * xDelta + yDelta * yDelta);
final Point closestPoint;
if (u < 0)
{
closestPoint = new Point(sx1, sy1);
}
else if (u > 1)
{
closestPoint = new Point(sx2, sy2);
}
else
{
closestPoint = new Point((int) Math.round(sx1 + u * xDelta), (int) Math.round(sy1 + u * yDelta));
}
return closestPoint;
}
}
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