Hi,
This would require a layout engine, and the Open-Xml-Sdk does not contain a layout engine.
As far as I know, there is no open source Open XML layout engine. There may be proprietary layout engines, but I have no experience with them.
However, if I had to calculate something like this, I would first use the FormattingAssembler module in Open-Xml-PowerTools to ‘roll-up’ all of the styling information into local styling.
Screen-Cast: Introducing the FormattingAssembler Module
Watch the screen-cast at the bottom.
After running FormattingAssembler, you have a new Open XML document where all styling (including positioning of the paragraph) are stored locally in the paragraph and run properties. You can then calculate positions based on the values stored in the markup.
But this is not going to be the same as using Word automation, which takes advantage of the internal layout engine in Word.
Cheers, Eric