- points.push_back (Offset (number->extent (commonx, X_AXIS).center () - x0,
- number->extent (commony, Y_AXIS)[dir]));
+ {
+ Interval x_ext = robust_relative_extent (number, commonx, X_AXIS);
+ Interval y_ext = robust_relative_extent (number, commony, Y_AXIS);
+ points.push_back (Offset (x_ext.center () - x0, y_ext[dir]));
+ }