Hi all!
Atm, feDisplacementmap output depends on zoom factor (see herehttps://bugs.launchpad.net/inkscape/+bug/182059 ). I had a look at the code to try to fix this, but I need someone to validate the code. Precise meaning of area, unit transforms, and particulraily of the function "enlarge_area" are not perfectly clear to me.
The modifs are all in nr-filter-displacement-map.cpp.http://launchpadlibrarian.net/11804938/nr-filter-displacement-map.cpp I just changed "scale" with "scalex" and "scaley" defined as:
Matrix trans = units.get_matrix_primitiveunits2pb(); double scalex = scale*trans.expansionX(); double scaley = scale*trans.expansionY();
where apparently appropriate (in the render() and enlarge_area() methods), but I would feel more confortable if someone having a better understanding of the code could check if this is correct or if other changes are needed elsewhere... Thanks! jfb.