For whatever reason we only want the DPI scaling from the given transform, and
not any other property of the transform.

When adding a link to process later, the transform has at that moment also a translate in it.

Before 1ffd271 the used transform was after the last page was
processed. At that moment the transform only had a scale component and no translate.

Yes, those classes are copies, so there is duplication. But before extending this method
I rather have it only in one place.

…ing box of the shape.