Re: bookTitleMarkup and tocItem cause empty page

[Jean Abou Samra]

Le 01/06/2022 à 21:12, Simon Albrecht a écrit :
> Hi Jean,
>
> On 01/06/2022 15:24, Jean Abou Samra wrote:
> > Please give an example.
>
>
> I’ve gone debugging, and it’s a weird combination of two things that 
> causes the empty page:
>
> %%%%%%%%%%%%%%%%%%%%%%%
> \version "2.23.9"
>
> \paper {
>   bookTitleMarkup = \markup {
>     \vspace #.3
>   }
> }
>
> \bookpart { \markup { 1 } }
>
> \tocItem \markup "toc2"
> \bookpart { \markup { 2 } }
> %%%%%%%%%%%%%%%%%%%%%%%%%
>
> I don’t understand… in my real-world book, the empty pages were empty, 
> now in this tiny example the second bookpart appears to get 
> duplicated, and this only because the bookTitleMarkup contains 
> _anything_ other than empty \fromproperty calls. Even \markup\null as 
> bookTitleMarkup has the bug (?) occurring.



OK, opened https://gitlab.com/lilypond/lilypond/-/issues/6358
about that. The thing is, \tocItem works by inserting a label
at the point it is being used. Since the label is a standalone
object between two bookparts, it is being made a bookpart
of its own! Without a title, that bookpart has no pages, but
if you have a title, it becomes visible ...

As said on the ticket, you need to move \tocItem inside
the second bookpart, like this:

\version "2.23.9"

\paper {
  bookTitleMarkup = \markup {
    \vspace #.3
  }
}

\bookpart { \markup { 1 } }

\bookpart {
  \tocItem \markup "toc2"
  \markup { 2 }
}


Best,
Jean