Thank you very much guys, this has been most helpful. At the moment I run the program as Alan suggests. However, the goal is to incorporate the program into Glade2 GUI and I am not sure that it will work with Tk, although I must admit I have not tried it out yet.
Abu Ismail On 4/18/07, János Juhász <[EMAIL PROTECTED]> wrote: > Hi Abu, > > > Question: how to determine whether point C is to the left or to the > > right of the line AB? > > When the line given by A(Xa,Ya) and B(Xb, Yb), > the area of the A-B-C triangle can be calculated with the value of next > determinant / 2 > > | Xa, Ya, 1 | > | Xb, Yb, 1 | > | Xc, Yc, 1 | / 2 > > So: > > Area = ( Xa(Yb-Yc) - Xb(Ya-Yc) + Xc(Ya-Yb) ) / 2 > > Area > 0 | the points are clockwise (C is on the left) > Area < 0 | the points are counterclockwise (C is on the right) > Area = 0 | the points are on the same line > > > It can be written in a python function > > ########### > def TriArea(a, b, c): > #Area = (Xa(Yb-Yc) - Xb(Ya-Yc) + Xc(Ya-Yb)) /2 > return ( a[0] * (b[1]-c[1]) - b[0] * (a[1]-c[1]) + c[0] * (a[1]-b[1]) > )/2 > > ########### > # to test it. > print TriArea((0,0), (10,0), (2,2)) > print TriArea((0,0), (10,0), (2,-2)) > print TriArea((0,0), (10,0), (2,0)) > ########### > > > The biggest advantage of this calculation is that, > it never goes to zero division exception. > > > > Best regards, > Janos > _______________________________________________ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor > _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
