Re: \center-column broken

[Aaron Hill]

On 2021-02-14 7:08 am, Johannes Feulner wrote:
> Hi there,
>
> \center-column is broken. In 2.18 it was still OK. The lines of a
> \center-column are supposed to be centered under each other. This is
> at least with 2.23.1 not any longer the case. Please, see attached
> pictures. The "aaaa" is clearly not centered unter the "|".
>
>    \version "2.18.0"
>
>    { a'1 a'1
>       c'' ^\markup
>      \center-align \box \bold \fontsize #10 \center-column { "|" "aaaa"
>    "bbb" "|" }
>    }

For reference, I see the correct behavior with 2.22.0 and 2.23.0, 
testing with both PDF and cropped PNG output.  (Latest on lilypond.org 
is 2.23.0-1, so are you compiling something yourself?)

Ultimately, this is a bug with how the glyphs are being rendered, not 
one related to centering.  Specifically, the wrong font is being 
rendered compared to the one that determined the physical extent.  If 
the narrower-looking letters had been intended, \box would have been 
much tighter around the markup.  This looks like an issue you would get 
with poor font substitution, so are you able to rule out issues with 
your PDF viewer and environment?


> Another problem is with \center-align. \center-align centers its
> contents (here the box) over the left edge of the note it is attached
> to. This does not look very centered at all. It should be centered
> over the middle of the note's x-extent. This was already wrong in
> 2.18.

You need to adjust parent-alignment-X as desired:

%%%%
\version "2.22.0"

{ a'1 a'1
  c'' -\tweak parent-alignment-X #CENTER
      ^\markup \center-align \box \bold \fontsize #10
               \center-column { "|" "aaaa" "bbb" "|" } }
%%%%


-- Aaron Hill