Re: misplaced-note-head bug (issue 5303)

[Lukas-Fabian Moser]

Folks,

only now was I able to do regression tests regarding my proposed fix(es) 
of the misplaced-note-head-bug (issue 5303):

The bug is caused by the integer-cast

lastpos = int (p);

in lily/stem.cc:629.

Replacing it by either
i) lastpos = p; // use float value
or
ii) lastpos = int (round (p)) // correctly round to integer

resolves the bug. Neither variant introduces regressions (differences 
only in in test-output-distance and rest-dot-position, the latter being, 
I think, unrelated - the seemingly random position changes of dots to 
multi-voice simultaneous rests).

Questions:

a) How to decide which fix is "better"? (My guess that using floats 
might pose the danger of rounding errors adding up until something bad 
happens - probably only for huge chords comprising hundreds of notes, 
but I'd tend to favor the solution with rounding.)

b) Would anybody be willing to shepherd a patch through the review process?

c) Does the situation warrant inclusion of a new regression test? (The 
example in the bug report on 
https://sourceforge.net/p/testlilyissues/issues/5303/ would be suitable 
I think.)

Best
Lukas

fix-misplaced-notehead-bug-use-float-value.diff
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fix-misplaced-notehead-bug-round-to-int.diff
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