// http://villemin.gerard.free.fr/GeomLAV/Triangle/Calcul/RelQuel_fichiers/image089.jpg
// C = point to check, A = first point of line, B = second point of line
public static double GetDistancePointToLine(ZZCoordinate firstPoint, ZZCoordinate secondPoint, ZZCoordinate toCheck)
{
// Calculation of the triangle' sides' length
double b = ZZMath.GetDistance(firstPoint, toCheck);
double c = ZZMath.GetDistance(firstPoint, secondPoint);
// Calculation of one of the angle attached to the straight line
double angleFirstPoint = ZZMath.AngleFrom3Points(secondPoint, firstPoint, toCheck, true);
// double angleA = angleARadian / (Math.PI / 180.0); // Falcultative: to know the angle in degrees
double h = b * Math.Sin(angleFirstPoint); // Perpendicular distance
double c1 = b * Math.Cos(angleFirstPoint); // Distance between firstPoint base of h (can be negative)
double c2 = c - c1; // Distance between secondPoint base of h (can be negative)
double clickCoordToFirstPoint = GetDistance(c1, h); // Distance between toCheck and firstPoint
double clickCoordToSecondPoint = GetDistance(c2, h); // Distance between toCheck and secondPoint
if (c1 >= 0 && c2 >= 0) // toCheck is between firstPoint and secondPoint perpendicularly
{
return(h);
}
else // toCheck isn't betwwen firstPoint and secondPoint
{
return((clickCoordToFirstPoint < clickCoordToSecondPoint) ? clickCoordToFirstPoint : clickCoordToSecondPoint);
}
}
public static double SlopeAngle(ZZCoordinate firstPoint, ZZCoordinate nextPoint, bool degres = true)
{
double dx = nextPoint.X - firstPoint.X, dy = nextPoint.Y - firstPoint.Y;
double slopeAngle;
if (dx == 0) // Vertical slope
{
slopeAngle = (dy > 0) ? 90 : -90; // Upward / Downward
}
else if (dy == 0) // Horizontal slope
{
slopeAngle = (dx > 0) ? 0 : 180; // Right / Left
}
else
{
slopeAngle = ZZMath.ToDegrees(Math.Atan(dy / dx));
if (dx < 0)
{
slopeAngle += 180;
}
else if (dy < 0)
{
slopeAngle += 360; // Because ATan return a negative angle in the 2th and 4th quarter, but the 2th is made positive thanks to the +180
}
}
return((degres) ? slopeAngle : ZZMath.ToRadians(slopeAngle));
}
public static double SlopeAngle(ZZCoordinate firstPoint, ZZCoordinate nextPoint, bool degres = true)
{
double dx = nextPoint.X - firstPoint.X, dy = nextPoint.Y - firstPoint.Y;
double slopeAngle;
if (dx == 0) // Vertical slope
{
slopeAngle = (dy > 0) ? 90 : -90; // Upward / Downward
}
else if (dy == 0) // Horizontal slope
{
slopeAngle = (dx > 0) ? 0 : 180; // Right / Left
}
else
{
slopeAngle = ToDegrees(Math.Atan(dy / dx));
if (dx < 0)
{
slopeAngle += 180;
}
}
slopeAngle = ZZFunctions.nmod(slopeAngle, 360);
return((degres) ? slopeAngle : ToRadians(slopeAngle));
}
// https://stackoverflow.com/questions/1211212/how-to-calculate-an-angle-from-three-points
// http://villemin.gerard.free.fr/GeomLAV/Triangle/Calcul/RelQuel_fichiers/image089.jpg
public static double AngleFrom3Points(ZZCoordinate pointBefore, ZZCoordinate anglePoint, ZZCoordinate pointAfter, bool degres = true)
{
// Calculation of the triangle' sides' length
double a = GetDistance(pointBefore, pointAfter);
double b = GetDistance(anglePoint, pointAfter);
double c = GetDistance(anglePoint, pointBefore);
// Calculation of one of the angle attached to the straight line
double alpha = Math.Acos((-Math.Pow(a, 2) + Math.Pow(b, 2) + Math.Pow(c, 2)) / (2 * b * c));
return((degres) ? alpha * (180 / Math.PI) : alpha);
}
public static double GetDistance(ZZCoordinate coord)
{
ZZCoordinate zero = new ZZCoordinate(0, 0);
return(System.Math.Sqrt(System.Math.Pow(zero.X - coord.X, 2) + System.Math.Pow(zero.Y - coord.Y, 2)));
}
public static double GetDistance(ZZCoordinate coord1, ZZCoordinate coord2) => System.Math.Sqrt(System.Math.Pow(coord1.X - coord2.X, 2) + System.Math.Pow(coord1.Y - coord2.Y, 2));
public static ZZCoordinate GetCenterOfSegment(ZZCoordinate pt1, ZZCoordinate pt2)
{
return(new ZZCoordinate((pt1.X + pt2.X) / 2.0, (pt1.Y + pt2.Y) / 2.0));
}
