Re: Extend Beam::shift_region_to_valid() to also take into account collisions. (issue4239047)

[mtsolo]

Great work!  Two comments below concerning beam properties.


http://codereview.appspot.com/4239047/diff/3002/lily/beam.cc
File lily/beam.cc (right):

http://codereview.appspot.com/4239047/diff/3002/lily/beam.cc#newcode1156
lily/beam.cc:1156: Real min_y_size = 2.0;
here, we should have something like
if (to_boolean (me->get_property ("avoid-collisions"))
so that users can opt out of the avoidance if they so choose.
then, we would have an `else' that set the collision penalty in the
quanting to 0 so that no collision avoidance took place.

I think that in a lot of real-music scenarios such as organ scores,
people's may in fact want beams to collide, and thus, they should be
able to opt-out of this avoidance.

http://codereview.appspot.com/4239047/diff/3002/lily/beam.cc#newcode1256
lily/beam.cc:1256: beam_left_y = point_in_interval (best, 2.0);
Here, there should be a padding property that allows users to control
breathing room for collisions.  Otherwise, you could wind up getting a
beam that is pushed just below a notehead in the quanting (see example
in next email).

http://codereview.appspot.com/4239047/