This static computation step performs manual linebreaks on all paragraphs. This transforms the pool-collection into the lines-collection.
For now, we follow a very simple path: A paragraph cannot be validated, if it is not yet closed. The linebreaking, be it the static one here or the dynamic one later, must be redone when the paragraph changes.
Splitting for linebreaks happens only between inline-boxes. BlockBoxes that are contained in inline-boxes (like 'inline-block' elements or 'inline-tables') are considered unbreakable according to the CSS specs. Linebreaking can be suspended in these cases.
As paragraphs itself are block elements, the linebreaks can be done iterative, using a simple stack to store the context of possibly nested paragraphs. The paragraph's pool contains the elements that should be processed, and the line-container will receive the pool's content (contained in an artificial inline element, as the linecontainer is a block-level element).
Change-tracking should take place on the paragraph's pool element instead of the paragraph itself. This way, only structural changes are taken into account.
@author Thomas Morgner