Comment 1 for bug 1424798

just 2 more pieces of info:
- the parameters W and H are also being rescaled at the same time, but one would normally not pay attention to that because they get overwritten as soon as something is drawn
- the rescaling is occurring during the file save process, not the file load. In other words, if you interrogate the preferences to see the values of Rx, Ry, they will agree with what appears on the next load, not the previous one