Dashed slur proposal

[Bertalan Fodor]

Hello, I wanted to contribute a patch for nicer slurs, but I don't 
really know how to do it.

I've found that dashed slurs are quite ugly. That's because 
output-ps.scm sets the dash length to the property Slur.dashed, but the 
gap between dashes is set to 10*slur.thickness, that is not good. I've 
found that changing output.scm's

  (ly:number->string (* 10 thick))
  " ] 0 draw_dashed_slur"))

to

  (ly:number->string (* 1.5 dash))
  " ] 0 draw_dashed_slur"))

I get much better results. However, the dots in dotted slurs (that is 
dashed=1.0) get too close to each other.

So it is obvious there should be a property called gap length or 
gap-factor to be able to set either:
  (ly:number->string (gaplength))
  " ] 0 draw_dashed_slur"))

or

  (ly:number->string (* gapfactor dash))
  " ] 0 draw_dashed_slur"))

Now, the thing I do not know is how to set up an other property.

I would be happy if you could help me.

Thank you,

Bert