protected virtual SLExpression VisitTwoPointsLine(TwoPointsLineExpression twoPointsLineExpression)
{
var point1 = Visit(twoPointsLineExpression.Point1);
var point2 = Visit(twoPointsLineExpression.Point2);
if (point1 != twoPointsLineExpression.Point1 || point2 != twoPointsLineExpression.Point2)
{
return(new TwoPointsLineExpression
{
Point1 = (PointExpression)point1,
Point2 = (PointExpression)point2
});
}
return(twoPointsLineExpression);
}
private static CoordinatesPointExpression GetIntersectionPoint(TwoPointsLineExpression line1, TwoPointsLineExpression line2)
{
var l1p1 = (CoordinatesPointExpression)line1.Point1;
var l1p2 = (CoordinatesPointExpression)line1.Point2;
var l2p1 = (CoordinatesPointExpression)line2.Point1;
var l2p2 = (CoordinatesPointExpression)line2.Point2;
// y = ax + c
var a1 = (l1p1.Y - l1p2.Y) / (l1p1.X - l1p2.X);
var c1 = l1p1.Y - l1p1.X * a1;
// Ax + By = C
var A1 = -a1;
var B1 = 1;
var C1 = c1;
var a2 = (l2p1.Y - l2p2.Y) / (l2p1.X - l2p2.X);
var c2 = l2p1.Y - l2p1.X * a2;
var A2 = -a2;
var B2 = 1;
var C2 = c2;
var delta = A1 * B2 - A2 * B1;
if (delta == 0)
{
throw new ArgumentException("Can't compute intersection of parallel lines.");
}
var x = (B2 * C1 - B1 * C2) / delta;
var y = (A1 * C2 - A2 * C1) / delta;
return(new CoordinatesPointExpression
{
X = x,
Y = y,
});
}