pngrutil.c
fprintf(stderr,"wx=%ld, wy=%ld, rx=%ld, ry=%ld\n",
int_x_white, int_y_white, int_x_red, int_y_red);
fprintf(stderr,"gx=%ld, gy=%ld, bx=%ld, by=%ld\n",
int_x_green, int_y_green, int_x_blue, int_y_blue);