Re: Getting absolute position of objects

[Knut Petersen]

I also need to output the absolute coordinates of all objects on the page, to generate training data for optical music recognition. I'm trying to print some information in \applyOutput, and I see that NoteHead X-offset and Y-offset are 0, and X-parent, Y-parent, X-positions, and Y-positions all seem to be (). Is there a way to get the absolute coordinates, so that I can add them to event-listener.ly?

It certainly is possible, but you need to implement an after-line-breaking function. There you can access the paper variables (margins etc.) as well as the xy-position of grobs. You may have a look at videohelper.ily file I published on this list on 2017-07-21. There is a function mkvideo-dump that easily could be extended to meet your requirements.

Knut