How to use FOP in wysiswyg editor, or how to speed up

[Tomáš Studva]

Hi developers, We are using FOP as rendering engine for FO in wysiwyg xml editor http://sourceforge.net/projects/euromath2. When opening about 40 page fo document, the editation is ugly slow. We can track changes in source document(also in case using XSLT), but  there is a principal error, because we don’t know how to update the FOP produced trees, so new FOP is created to layout document after change and further render by Draw2d (we implemented some basic renderer composed of Draw2D Figures, which are organized into tree). I’ ve also profiled our application on such big document, from typing to update of screen and found out, than FOP consumes 1/3 of processor time, that is too much if we optimize anything but not FOP- it takes on good PC  about 10 seconds, so FOP 10/3 = 3sec.   So, is there possibility to update the FOP produced trees according to change in XML (to use it in editor manner, not only rendering engine)? Or if not, is there possibility to recycle FOP PageSequence which haven’t changed? And last, is there option to speed up FOP generally, by lowering output quality or something?   Thanx, Tomas Studva