(Adding Aaron in CC.) Le 07/11/2021 à 12:39, Thomas Morley a écrit :
Hi,commit 94860164493ab3a209986b0e3662ff7bd8958cb5 Author: Mike Solomon <m...@apollinemike.com> Date: Mon Mar 28 10:58:29 2011 -0400 Assures smooth transitions at glissando line breaks. When a glissando breaks over lines, the left point of the beginning-of-line glissando picks up on the y-axis where the right point of the end-of-line glissando ends. is not true for cross-staff, broken Glissando. For a down-pointing Glissando, ending in a lower Staff this "pick-up" point is not matched. For an up-pointing Glissando starting in a lower Staff the first part is completely off. This is https://gitlab.com/lilypond/lilypond/-/issues/4806 See attachment.
I get seemingly correct output in the issue's example when adding \override Glissando.simple-Y = ##f So I'd start by investigating why simple-Y was added in the first place.
While attempting to code stemmed Glissandi in scheme, there was a very helpful discussion starting here: https://lists.gnu.org/archive/html/lilypond-user/2021-10/msg00326.html lastly arriving at https://lists.gnu.org/archive/html/lilypond-user/2021-11/msg00003.html Basically I try to get start- and end-points of all kinds of Glissandi, printing crosses there. Many thanks to Aaron! That said,... If I always compensate the right ending-point with (pseudo-code) (ly:grob-relative-coordinate <Glissando-grob> <System-grob> Y) Then the crosses are at those positions Mike's patch promises.
Really System? Isn't this going to create a cyclic dependency between the stencil and vertical alignment for non-cross-staff glissandi via VerticalAxisGroup skylines? Off the top I would think it should be a matter of correcting reference points (see above).
I attach the new scheme-code and an image (with correct placed crosses, but untouched default-stencil) Ofcourse it's trivial to extend this scheme-code to create Glissando-stencil instead of those crosses. Better ofcourse is fixing the problem in our source. Alas, because my lack of C++-knowledge, I can't do it myself.
You should learn C++ someday :-) Best, Jean
