private bool FindIntersectingPoints(double x11, double y11, double x12, double y12, double x21, double y21, double x22, double y22)
{
double pixelHeight;
pixelHeight = bitmap.PixelHeight;
if (y11 <= -pixelHeight)
{
y11 = -2 * pixelHeight;
}
if (y12 <= -pixelHeight)
{
y12 = -2 * pixelHeight;
}
if (y21 <= -pixelHeight)
{
y21 = -2 * pixelHeight;
}
if (y22 <= -pixelHeight)
{
y22 = -2 * pixelHeight;
}
if (y11 >= 2 * pixelHeight)
{
y11 = 4 * pixelHeight;
}
if (y12 >= 2 * pixelHeight)
{
y12 = 4 * pixelHeight;
}
if (y21 >= 2 * pixelHeight)
{
y21 = 4 * pixelHeight;
}
if (y22 >= 2 * pixelHeight)
{
y22 = 4 * pixelHeight;
}
intersectingPoint = new Point();
// First line slope and intersect( y = mx+c )
double m = WriteableBitmapExtensions.Slope(x11, y11, x12, y12);
double c = double.NaN;
if (!double.IsInfinity(m))
{
c = WriteableBitmapExtensions.Intersect(x12, y12, m);
}
// Second line slope and intersect
double m1 = WriteableBitmapExtensions.Slope(x21, y21, x22, y22);
double c1 = double.NaN;
if (!double.IsInfinity(m1))
{
c1 = WriteableBitmapExtensions.Intersect(x21, y21, m1);
}
// point intersecting for both straight line.(Cross point for lines)
double x = (c1 - c) / (m - m1);
intersectingPoint.X = (int)x;
intersectingPoint.Y = (int)(m * x) + c;
return((double.IsNaN(x) || double.IsNaN(intersectingPoint.Y)) ? false : true);
}