Re: Add scheme procedure that gets paper column rank (issue 281020043 by address@hidden)

[paulwmorris]

On 2015/12/15 22:26:01, dak wrote:
> Not sure what you need it for.

I was working on a Scheme rewrite of ly:ledger-line-spanner::print,
to allow for some local customizations.  It uses the rank of paper
columns,
namely, around line 210 in ledger-line-spanner.cc

          Direction vdir = Direction (sign (pos));
          int rank = h->get_column ()->get_rank ();

          reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
          reqs[rank][vdir].head_extent_.unite (head_extent);
          reqs[rank][vdir].position_
            = vdir * max (vdir * reqs[rank][vdir].position_, vdir *
pos);

For each note head the code gets the rank of the note head's paper
column as a way to effectively associate the note heads that belong
to the same column... and thus calculate, for each column, the furthest
note head position, how wide the ledger lines need to be, etc.

> Would it be more generic to provide
> spanned_rank_interval ()?  That should be defined for every grob.
Probably also
> for paper columns?

I don't know enough about spanned_rank_interval to say for sure.  (I
looked
it up in grob.cc)  If it could be used to group note heads by paper
column
(as with paper column rank) then it should work and be more generic.


https://codereview.appspot.com/281020043/