int dx = compute_delta(cgeom.x, cgeom.w, origin_x, origin_dim, nav_x);
int dy = compute_delta(cgeom.y, cgeom.h, origin_y, origin_dim, nav_y);
int dx = compute_delta(cgeom.x, cgeom.w, origin_x, origin_dim, nav_x);
int dy = compute_delta(cgeom.y, cgeom.h, origin_y, origin_dim, nav_y);