#include "plplot.h"

/* Determines if point (px,py) lies above the line joining (sx1,sy1) to */
/* (sx2,sy2). It only works correctly if sx1 <= px <= sx2  */

int plabv(px, py, sx1, sy1, sx2, sy2)
int px, py, sx1, sy1, sx2, sy2;
{
      int above;

      if (py >= sy1 && py >= sy2) 
        above = 1;
      else if (py < sy1 && py < sy2)
        above = 0;
      else if ((sx2-sx1) * (py-sy1) > (px-sx1) * (sy2-sy1)) 
        above = 1;
      else
        above = 0;

      return(above);
}