Re: Spacing with empty contexts; issue 1669 (issue 4515158)

[mtsolo]

https://codereview.appspot.com/4515158/diff/2009/lily/align-interface.cc
File lily/align-interface.cc (right):

https://codereview.appspot.com/4515158/diff/2009/lily/align-interface.cc#newcode222
lily/align-interface.cc:222: dy = max (dy, min_distance);
On 2011/06/09 02:55:55, Keith wrote:
> On 2011/06/07 04:48:01, joeneeman wrote:
> > If pure is true, there may be some staves that are going to be
removed.
> However,
> > these staves won't be removed until after line-breaking.

> ... and, as you say, these staves are not yet removed when
Y-extent-estimates
> for the page breaker are calculated, so this patch messes up the page
breaker.

> If the page breaker depends on empty, but living, staves disappearing
for
> vertical spacing purposes, then maybe empty staves should be treated
that way
> consistently. That would be tantamount to giving all empty-able
contexts the
> hara-kiri engraver, as you suggested much earlier.

> The obvious alternative would be to have the empty staves decide
whether to
> suicide before page breaking, but my suspicion is that is awkward, or
it would
> have been done that way at first.

> Having minimum_distances() change behavior based on whether 'pure' is
true is
> too tricky for me. (how do we know that any staff that is empty we are
pure will
> suicide later)

> I'll think on it, but mark the patch as abandoned for now.

Couldn't there just be a vector<bool> ignore_me that contains the result
request_suicide for all elements (when pure)?  Then, the for loop would
be continued for these elements and they wouldn't have to be removed in
get_skylines.

https://codereview.appspot.com/4515158/