Re: Duplication of pages with slight changes to color of grobs?

[Knut Petersen]

Hi David!
> > > Would it help to define your own custom properties (grob or context)
> > > to avoid overloading the color property.  I have this in my include
> > > file for Clairnote:
> > Interesting approach ... I think it would only shift the problem to
> > other places in the code.
> Well, but they might be less surprising.  I am also not sure that our
> color? definition is the knee's bees: it does not appear suitable for
> CMYK or RGBA or other possibly backend-specific definitions.
>
> Still, a color that is not actually fixed at the time a grob is put to
> "paper" seems strange, to say the least.

Indeed, it is strange, but it works very well ;-)

What do you think about the possible extensions to lilypond described below?

It would be helpful for video generation to define videohack? with a default of 
#f at the toplevel  and to let color? and setcolor change its behaviour 
according to that flag. color? would skip checking the range of the numbers, 
setcolor would emit colors with an extended precision.

dump-page could be  extended to allow inclusion of some additional postscript 
code at the beginning and at the end of a page. That could also be useful for a 
number of other purposes. dump-page would check if an alist with key page 
number would define some code to emit for the page it processes.

A last nice hook would be to change write-preamble in a way to write some user-defined 
postscript code immediately before it emits "%%EndProlog".

@Karl: I know that I'm not the only one who likes to process the postscript 
code generated by lilypond. What do you think about the topic?

Knut