// /usr/libexec/gcc/i686-pc-linux-gnu/3.4.3-20050110/cc1 -quiet -I. -I. -I../.. -I../.. -I../../dynagraph -I../../cdt -I../../agraph -MD .libs/xlines.d -MF .deps/xlines.Tpo -MP -MT xlines.lo -MQ .libs/xlines.o -DHAVE_CONFIG_H -DPIC xlines.c -mno-sse2 -fstack-protector -fstack-protector-all -quiet -dumpbase xlines.c -march=pentium3 -auxbase-strip .libs/xlines.o -g -O2 -Wall -fPIC -o - -frandom-seed=0
# 1 "xlines.c"
# 1 "/var/tmp/portage/graphviz-1.16/work/graphviz-1.16/dynagraph/common//"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "xlines.c"
# 54 "xlines.c"
int gems_lines_intersect( x1, y1,
       x2, y2,

       x3, y3,
       x4, y4,

       x,
       y

               )
double
    x1, y1, x2, y2, x3, y3, x4, y4,
    *x, *y;
{
    double a1, a2, b1, b2, c1, c2;
    double r1, r2, r3, r4;
    double denom, offset, num;





    a1 = y2 - y1;
    b1 = x1 - x2;
    c1 = x2 * y1 - x1 * y2;





    r3 = a1 * x3 + b1 * y3 + c1;
    r4 = a1 * x4 + b1 * y4 + c1;





    if ( r3 != 0 &&
         r4 != 0 &&
         ((r3 >= 0.0) == (r4 >= 0.0)))
        return ( 0 );



    a2 = y4 - y3;
    b2 = x3 - x4;
    c2 = x4 * y3 - x3 * y4;



    r1 = a2 * x1 + b2 * y1 + c2;
    r2 = a2 * x2 + b2 * y2 + c2;






    if ( r1 != 0 &&
         r2 != 0 &&
         ((r1 >= 0.0) == (r2 >= 0.0)))
        return ( 0 );




    denom = a1 * b2 - a2 * b1;
    if ( denom == 0 )
        return ( 2 );
    offset = denom < 0 ? - denom / 2 : denom / 2;
offset = 0.0;






    num = b1 * c2 - b2 * c1;
    *x = ( num < 0 ? num - offset : num + offset ) / denom;

    num = a2 * c1 - a1 * c2;
    *y = ( num < 0 ? num - offset : num + offset ) / denom;

    return ( 1 );
    }