This method computes the position of the separator according to the specification of the parameters. The calculation is affected by the packing parameters of the child widgets depending on whether they can resize and shrink. This method is used by subclasses of GtkPaned and is usually not needed by applications. the queue_resize() method must be called after this method to have the resizing displayed.
The minimum position is 0 if child1's shrink value is true or the value of child1_req, if false. The maximum position is the value of allocation if child2's shrink value is true, or the value of (allocation - child2_req), if false. The final calculated position will be between the minimum and maximum positions.