Hi Urs, On Thu, May 17, 2012 at 5:08 AM, Urs Liska <li...@ursliska.de> wrote:
> Hi, > > I am very much enjoying now to tweak slurs and other curves using offsets > instead of hardcoded control-points. > > I wonder if it would be interesting to have a similar approach to grobs > with a positions property (e.g. beams). > While it is comparably easy to find usable #'positions for a beam this is > then of course hard-coded and won't work if either the system-system > spacing changes for whatever reason, or the music is transposed. > > Of course it must be quite straightforward to read out lilypond's decision > and apply offsets to that in a music function? > One issue here is that 'positions of Slur are calculated differently from Beam. You can find a function which offsets 'positions of Slur here: http://lsr.dsi.unimi.it/LSR/Snippet?id=748 Basically, this function offsets the Y-coordinate of the first and last control-points. For something like Beam, you can do something like this: \version "2.15.38" offsetBeamPositions = #(define-music-function (parser location offsets) (pair?) #{ \once \override Beam #'positions = #(lambda (grob) (let* ((func (assoc-get 'positions (cdr (ly:grob-basic-properties grob)))) (pos (func grob))) ; both of above assignments may be replaced by: ; (pos (beam::place-broken-parts-individually grob)) (coord-translate pos offsets))) #}) \relative c'' { \offsetBeamPositions #'(-1 . -2) c8[ d e f] } I imagine that this could be generalized to cover other grobs using the 'positions property. With that in mind, I've had it look up the callback which calculates 'positions (the commented-out lines give you a variant which uses that specific callback for Beam). (Thank you Harm for showing me this method.) > And if that works one could even enhance the \shape function? > The wrapper function could check against a list of grob names and call the > appropriate helper function (i.e. if its a Slur then call shape-curve). > Maybe it's even possible to make that still more generic. Is it possible > to check if a given grob has a given property? (i.e. if the grob has a > control-points property then call shape-curve, else if it has positions > then call shape-positions [elseif used so that a slurs control-points take > precedence over its positions]). > > So it could be possible to write > shape Slur #'((1 . 0) (3 . -2) (0 . 0) (0 . 1)) > or > shape Beam #'(2 . -1) > or > shape Arpeggio #'(-1 . 2) > > Would be awesome I think. > > Maybe one could even have more ideas to make this offset approach even > more general/generic. > > Instead of ready-made functions, I would also appreciate hints on how to > achieve this (as said, I'm quite interested in getting used to write Scheme > functions myself, without always having to ask here). > Though it is entirely too much fun to work out these puzzles, I'll leave it at that! I hope what I've given you will give you a place to start with this. Best, David > Best > Urs > > ______________________________**_________________ > lilypond-user mailing list > lilypond-user@gnu.org > https://lists.gnu.org/mailman/**listinfo/lilypond-user<https://lists.gnu.org/mailman/listinfo/lilypond-user> >
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