Comment 4 for bug 318726

It all boils down to sp_use_bbox calling the deprecated version of sp_item_invoke_bbox_full, which is still using NRRects and which is known to have difficulties with bounding boxes having a zero dimension. The bigger picture IMHO is that we still need to replace all occurrences of NRRect by Geom::Rect, in each SPItemClass.

For the time being I've prepared a patch which prevents Inkscape from crashing. This patch will introduce inaccuracies though when transforming, but that's obviously better than crashing.