Find the point at which 2 lines intersect
May 11th, 2007
Given two lines ( defined as 2 x,y coordinates in an array ), this will return the x,y position at which the two lines intersect. If they do not intersect, it will return null.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 | public Coordinate intersects(Coordinate[] coA,Coordinate[] coB ) { double x11 = coA[0].getX(); double y11 = coA[0].getY(); double x12 = coA[1].getX(); double y12 = coA[1].getY(); double x21 = coB[0].getX(); double y21 = coB[0].getY(); double x22 = coB[1].getX(); double y22 = coB[1].getY(); double dx1 = x12 - x11; double dy1 = y12 - y11; double dx2 = x22 - x21; double dy2 = y22 - y21; double det = (dx2*dy1-dy2*dx1); Coordinate coReturn = null; if (det != 0.0) { double mu = ((x11 - x21)*dy1 - (y11 - y21)*dx1)/det; if (mu >= 0.0 && mu <= 1.0) { coReturn = new Coordinate(); coReturn.setX((int)(x21 + mu*dx2 + 0.5)); coReturn.setY((int)(y21 + mu*dy2 + 0.5)); } } return coReturn; } |
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