void gfxdrawer_target_poly(gfxdrawer_t*d, double gridsize);
void gfxpolywriter_init(polywriter_t*w);
void gfxdrawer_target_poly(gfxdrawer_t*d, double gridsize);
void gfxpolywriter_init(polywriter_t*w);
gfxpoly_t* gfxpoly_from_file(const char*filename, double gridsize);
void gfxpoly_destroy(gfxpoly_t*poly);
gfxpoly_t* gfxpoly_from_file(const char*filename, double gridsize);
void gfxpoly_destroy(gfxpoly_t*poly);