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fg_getfillside

Usage

   #include <fg.h>
   int fg_getfillside(const fg_coord_t *pt_pairs, unsigned int
   vertices)

Description

   Figure out which side of the polygon/outline, as it is traversed, the

   fill is  on. Return FG_FILL_ON_RIGHT or FG_FILL_ON_LEFT. The algorithm
   may  fail if line segments cross each other or are colinear. The last
   point pair in  the array pt_pairs must be equal to the first. May be used
   with  fg_filloutline to fill arbitrary shapes.

Example 

   fill_users_outline()
   {
       fg_coord_t *p, *buf;
       unsigned int point_pairs;
       char *s;

       point_pairs = get_users_outline(&p)

       if (point_pairs 0)
       {
           unsigned int buffer_size;

           int side = fg_getfillside(p, point_pairs)


           if (side == FG_FILL_ON_RIGHT)
               s = "Filling on the right side";
           else
           {
               assert(side == FG_FILL_ON_LEFT);
               s = "Filling on the left side.";
           }

           buffer_size = get_outline_buff_size(p, point_pairs);
           buf = malloc(buffer_size);
           if (buf)
           {
               fg_filloutline(FG_WHITE, FG_MODE_SET, ~0, p,
                   buf, point_pairs, side, fg.displaybox);
               free(buf);
           }
           else
               s = "Insufficient memory.";
       }

       else
           s = "No outline obtained.";

       fg_puts(FG_WHITE, FG_MODE_SET, ~0, FG_ROT0, 0, 0, s,
           fg.displaybox);
   }