Re: Better pure heights for slurs (issue 5431065)

[k-ohara5a5a]

LGTM
Removing the contribution from 'height-limit' to estimated slur heights
is very helpful.  It was never appropriate to add 'height-limit' to the
extent of the slurred notes, because the note or stem furthest in the
direction of the slur is much closer to the curve of the slur than
'height-limit'.  Piano music often has to increase height-limit, and the
formerly ridiculous height estimates made the page-breaker useless for
me.

Estimating the slur extent as an offset from the notes in the direction
of the slur, rather than a widening of the notes extent on both sides,
should also help a bit.

The stuff with slur slopes is fümms bö wö tää zää uu, but seems
harmless.



http://codereview.appspot.com/5431065/diff/8002/lily/slur.cc
File lily/slur.cc (right):

http://codereview.appspot.com/5431065/diff/8002/lily/slur.cc#newcode101
lily/slur.cc:101: ret[downup] = minmax (downup, d[dir], ret[downup]);
any different from ret.add_point(d[dir])

http://codereview.appspot.com/5431065/diff/8002/lily/slur.cc#newcode113
lily/slur.cc:113: // we dampen the height approximation by the slur's
likely slope
'height_approximation' now stores free_head_distance_, which is applied
vertically so its effect doesn't depend on slope of the slur.  Its value
is very small by default, and is only a request to the slur scoring
routine, so why bother with it?

http://codereview.appspot.com/5431065/diff/8002/lily/slur.cc#newcode114
lily/slur.cc:114: // steeper slopes get smaller factors
Without a count of the note-columns spanned, this is more of a height
than a slope.

And larger slopes/heights get larger 'factor's, smaller '(1 - factor)'s

http://codereview.appspot.com/5431065/diff/8002/lily/slur.cc#newcode116
lily/slur.cc:116: ret[dir] += height_approximation * (1 - factor);
dir *

http://codereview.appspot.com/5431065/