Controlling the imposition process

In the imposition process the pages to be placed in the pre-defined slots are positioned within the respective templates.

There are three steps of placing pages in the imposition process. They are carried out in this strict order:

  • rotation
  • scaling
  • relative placing

Rotating

If the configuration template SheetTemplateConfig.dat specifies a rota-­tion (anti-clockwise by 90, 180 or 270 degrees) for the slot concerned, the page from the source document which is about to be imposed is rotated accordingly before further processing (the source document will remain unaltered by this).

Scaling

Next the page to be imposed from the source document is scaled by the given factor (if a scaling factor of 0.5 has been entered the page will be scaled down to half its original size).

If the special scaling values 0.0 or -1.0 have been entered, the size of the page to be imposed from the source document is compared with the TrimBox measurements for the relevant slot. The necessary scaling factor is then calculated and the page is automatically scaled using this factor so that the TrimBox fits into the slot.

Relative Placing

Finally, according to the information for relative positioning, the following action will be carried out: the respective reference point – e.g. left edge vertical centered (LC) – is calculated for the page to be imposed as well as for the slot concerned and the page to be imposed is placed in the slot so that both reference points are exactly on top of each other. If a page needs to be rotated, it is important here to remember to calculate the reference point of the page to be imposed after this has happened.