public CustomLine(Point p1, double s) : this()
{
this.point1 = p1;
this.slope = s;
if (slope == 1e+10)
{
this.isVertical = true;
}
if (!isVertical)
{
this.c = CustomLine.calculateC(p1, slope);
}
;
this.point2 = this.calculatePoint2();
}
public CustomLine(Point p1, Point p2) : this()
{
this.point1 = p1;
this.point2 = p2;
this.slope = CustomLine.calculateSlope(p1, p2);
if (slope == 1e+10)
{
this.isVertical = true;
}
if (!isVertical)
{
this.c = CustomLine.calculateC(p1, slope);
}
;
}
public static bool withinLineSegment(Point point3, CustomLine l)
{
Point point1 = l.getPoint1();
Point point2 = l.getPoint2();
// we use sqrt here because getDistance does not actually sqrt
double p1p2 = (Utilities.getDistance(point1, point2));
double p1p3 = (Utilities.getDistance(point1, point3));
double p2p3 = (Utilities.getDistance(point2, point3));
if (p1p2 == (p1p3 + p2p3))
{
return(true);
}
else
{
return(false);
}
}
public static Point?getIntersectionCoordinates(CustomLine l1, CustomLine l2)
{
Point intersectionPoint = new Point();
// if parallel
if (l1.getSlope() == l2.getSlope())
{
return(null);
}
// if either one is vertical (but not both because we would have returned null already)
else if (l1.getIsVertical())
{
intersectionPoint.X = l1.getPoint1().X;
Point l2Point = l2.getPoint1();
intersectionPoint.Y = (intersectionPoint.X * l2.getSlope()) + l2.getConstant();
}
else if (l2.getIsVertical())
{
intersectionPoint.X = l2.getPoint1().X;
Point l1Point = l1.getPoint1();
intersectionPoint.Y = (intersectionPoint.X * l1.getSlope()) + l1.getConstant();
}
else
{
Point l1Point = l1.getPoint1();
Point l2Point = l2.getPoint1();
double a1 = l1Point.Y - l1.getSlope() * l1Point.X;
double a2 = l2Point.Y - l2.getSlope() * l2Point.X;
intersectionPoint.X = (a1 - a2) / (l2.getSlope() - l1.getSlope());
intersectionPoint.Y = a2 + l2.getSlope() * intersectionPoint.X;
}
return(intersectionPoint);
}
public static Point ClosestPointFromPointToPolygon(CustomPolygon polygon, Point point)
{
// we keep track of point with minimum distance
Point? minPoint = null;
double minDist = double.MaxValue;
List <CustomLine> polygonLines = polygon.GetPolygonLines();
// for each line in polygon, find the perpendicular line from point
for (int i = 0; i < polygonLines.Count(); i++)
{
CustomLine lineSegment = polygonLines[i];
double slope = lineSegment.getSlope();
double perpSlope = CustomLine.getPerpendicularSlope(slope);
CustomLine perpLine = new CustomLine(point, perpSlope);
Point? intersectionPoint = CustomLine.getIntersectionCoordinates(lineSegment, perpLine);
if (intersectionPoint.HasValue)
{
double dist = Utilities.getDistance(intersectionPoint.Value, point);
// does this line intersect the polygon line segment?
// is the intersection point and the point a min distance
if (CustomLine.withinLineSegment(intersectionPoint.Value, lineSegment) &&
dist < minDist)
{
minDist = dist;
minPoint = intersectionPoint;
}
}
else
{
throw new Exception("Intersection Point is null even though it should have a coordinate");
}
}
// If there is a minpoint we are good to go
if (minPoint.HasValue)
{
return(minPoint.Value);
}
// or else we calculate the closest distance from the point to the polygon corners
else
{
minDist = double.MaxValue;
PointCollection points = polygon.GetPoints();
for (int i = 0; i < points.Count; i++)
{
double dist = Utilities.getDistance(points[i], point);
if (dist < minDist)
{
minDist = dist;
minPoint = points[i];
}
}
}
// If there is a minpoint we are good to go
if (minPoint.HasValue)
{
return(minPoint.Value);
}
else
{
throw new Exception("Point with minimum distance is null even though it should have a coordinate");
}
}
private List <Double> getExtendedDistanceList(PointCollection points, Point clickPoint)
{
List <Double> extendedDistances = new List <Double>();
for (int i = 0; i < points.Count; i++)
{
Point objectivePoint = points[i];
// get the line from objective point to the clickpoint
CustomLine clickLine = new CustomLine(objectivePoint, clickPoint);
Point?intersectionPoint = null;
// we cycle through the polygon points 2 at a time, finding the polygon line
// that intersects with the extended clickLine
for (int j = 0; j < points.Count; j++)
{
Point currentPoint = points[j];
Point nextPoint;
if ((j + 1) < points.Count)
{
nextPoint = points[j + 1];
}
else
{
// if the point is the last point, we cycle back to get the point in the 0th index
nextPoint = points[0];
}
CustomLine polygonLine = new CustomLine(currentPoint, nextPoint);
intersectionPoint = CustomLine.getIntersectionCoordinates(clickLine, polygonLine);
// Make sure the intersection point calculated is not the objectivePoint
if (intersectionPoint.HasValue &&
// this part is trick af because it is floating point calculation. Need some offset
(!Utilities.floatsEqual(objectivePoint.X, intersectionPoint.Value.X, Constants.offset) ||
!Utilities.floatsEqual(objectivePoint.Y, intersectionPoint.Value.Y, Constants.offset))
&&
CustomLine.withinLineSegment(intersectionPoint.Value, polygonLine))
{
// if we have discovered the point we break out of the for loop
Console.WriteLine("the valid intersection point is ({0}, {1})", intersectionPoint.Value.X, intersectionPoint.Value.Y);
break;
}
}
// Get distance between the polygon corner and the intersecting coordinate
if (intersectionPoint.HasValue)
{
double extendedDistance = Utilities.getDistance(intersectionPoint.Value, objectivePoint);
extendedDistances.Add(extendedDistance);
}
else
{
// I should be getting some kind of intersection here if not
throw new Exception("Intersection Point is null even though it should have a coordinate");
}
}
return(extendedDistances);
}
