I'm a long time user of lilypond for drums. I have a problem for some time now with png generation. I describe it quite well (I hope so)here : http://www.nabble.com/PNG-size-issue-tf3131379.html. I tried to become a contributor :) I hope that's the right place and a quite godd way to do. Please tell me if not.
The bug remains in the last stable version of lilypond 2.10.25 on linux (I think it's also the case for other OS).
The problem seems to be in scm/ps-to-png.scm line 142. Here in lilypond has detected that the ps is multipage or not. if not gs is not called with
-dDEVICEWIDTHPOINTS and -dDEVICEHEIGHTPOINTS but with -dEPSCrop. I change these lines that way and the bug is gone. I'm not a lilypond hacker and I assume that if it was done this way it had a reason but I don't know which one. Can someone tell me if my code might break something ? if not could it be tested ? then commited ?