Re: multiple TextSpanners per voice

[David Nalesnik]

On Fri, Oct 2, 2015 at 5:59 PM, David Nalesnik <address@hidden> wrote:

On Fri, Oct 2, 2015 at 5:49 PM, David Nalesnik <address@hidden> wrote:

Horizontal_bracket_engraver achieves correct ordering of nested brackets through the side-position-interface array 'side-position-elements.  Brackets closer to the staff are added to the support of brackets further away.  However, this only works because 'outside-staff-priority is set to #f by default.  As soon as you set it to a numerical value, chaos ensues: the initial ordering is flipped AND the brackets flip orientation across line breaks.  (See attached images.)

So much for my analytical skills.  The blue bracket simply changes orientation across the line break with outside-staff-priority set to a number.

The problems with HorizontalBracket and TextSpanner may be "fixed" by setting 'padding to a value ever-so-slightly higher than the value of 'outside-staff-padding. Both grobs are assigned an outside-staff-padding of 0.46 in lily/axis-group-interface.cc.  So, if we set padding to 0.460000001, the ordering comes out OK when staff-priority is set.  (My conjecture is that by setting 'padding higher than 'outside-staff-padding we are signalling a collision, which is resolved by avoid_outside_staff_collisions in axis-group-interface.cc.)

So here is a revised version of the TextSpanner code.  The intention is to allow as many spanners per voice as you'd like.  This works with 'outside-staff-priority (set to 350 for TextSpanner, by default), but for the time being, you need to add the 'padding override to handle line breaks.  (Alternately, you could specify different staff-priorities for individual spanners, as was done earlier in this thread.)

I hope this is useful.  Suggestions for improvement welcome!

DN

scheme-text-spanner-id.ly
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