\visible_area_center

Description 

\visible_area_center allows to specify the point that is in the center of the area used to draw a step. Bounds of this zone is defined by \visible_area_height and \visible_area_width (cf. § and ). This operator is useful when one wants to focus on a peripheral zone of the diagram. It can also be useful combined with a scale operator. It takes only one parameter, the focus point which becomes the center of the visible space.
\visible_area_center can be found in different scope :

• inside step blocks (local)
• between step blocks (global)

If \visible_area_center is written inside a step block, the change of centering point defined by this operator is only applied for the current step. In the other case, if it is specified between two step blocks, the new focus becomes global, it is applied on all next steps. Local operator is always prioritary: if a global focus point has been defined before the current step, the local focus point is applied for this step but the global point is restored for next steps.

Usage

  \visible_area_center(o);

    ....

  \step {
    ....
    \visible_area_center(mid_ab); % focus this step around mid_ab point
    ....
  }

  \step {  
    ....  % the focus is still the o point
  }

Formal structure

  \visible_area_center(VERTEX);

Parameters

  VERTEX
  Description    : Indicates the name of the focus point. 
  Type           : Symbol, vertex identifier.
  Allowed values : Any vertex identifier previously defined.