Re: Gets vertical skylines from grob stencils (issue 5626052)

[joeneeman]

http://codereview.appspot.com/5626052/diff/23001/lily/axis-group-interface.cc
File lily/axis-group-interface.cc (right):

http://codereview.appspot.com/5626052/diff/23001/lily/axis-group-interface.cc#newcode659
lily/axis-group-interface.cc:659: vector<Grob *> *riders)
On 2012/02/16 10:08:39, MikeSol wrote:
> On 2012/02/16 08:09:10, joeneeman wrote:
> > I don't understand why riders are necessary. Is it because of this
cyclic
> > dependence stuff?

> Not cyclical, but imagine that a grob (say tuplet bracket, for
example) has its
> outside staff priority set whereas one of its Y_AXIS children (say
tuplet
> number, for example), doesn't.  If the tuplet number's skyline is
added to the
> skyline_pair using add boxes before its parent is shifted, it will be
placed too
> low in the skyline.  Thus, it must be added to the skyline only after
its
> parent's outside-staff-priority has been set to SCM_BOOL_F.  This is
why riders
> are used.

Could you document this reasoning, please?

http://codereview.appspot.com/5626052/diff/23001/lily/skyline.cc
File lily/skyline.cc (right):

http://codereview.appspot.com/5626052/diff/23001/lily/skyline.cc#newcode668
lily/skyline.cc:668: Skyline::left () const
On 2012/02/16 10:08:39, MikeSol wrote:
> On 2012/02/16 08:09:10, joeneeman wrote:
> > This is linear in the number of buildings, but it should be
constant.

> How would one do this?

The buildings are in increasing order, so this should work:

Real last_end = -infinity_f;
for (...)
  {
    if (i->y_intercept_ > -infinity_f)
      return last_end;
    last_end = i->end_;
  }
return infinity_f;

http://codereview.appspot.com/5626052/diff/23001/lily/skyline.cc#newcode680
lily/skyline.cc:680: Skyline::right () const
On 2012/02/16 10:08:39, MikeSol wrote:
> On 2012/02/16 08:09:10, joeneeman wrote:
> > Ditto

> Ditto

...and here it's a doubly-linked list so you can iterate backwards.

http://codereview.appspot.com/5626052/