Re: GSoC 2020: blot diameter and positioning of flags

[Werner LEMBERG]

> Emmentaler's flag glyphs are minimal: they deliberately don't
> overwrite a stem's tip, only overlapping with the stem in a thin,
> rectangular area [...]
> 
> However, SMuFL expects scoring programs to use plain rectangle primitives
> for drawing stems.  With this in mind, Bravura's flags cover up whatever
> (flat) stem tip may have existed, [...]
> 
> This means that, at the moment, the SMuFL standard alone cannot
> reliably reproduce Emmentaler's slightly variable flag positioning.

Well, LilyPond's solution is more versatile...

> A quick-and-dirty fix would be for LilyPond to set blot-diameter to
> 0 when a SMuFL font other than Emmentaler is loaded, which will
> result in sharp rectangle corners as SMuFL expects.  However, other
> programs wouldn't look quite the same with Emmentaler because of
> their straight rectangle stem primitives.

OK.

> For a full-on fix, I think it may be a good idea to see if we can
> get our blot-diameter / minimal flag concepts into SMuFL as a couple
> optional metadata items, so other fonts and notation programs can
> take advantage of them if they wish.  Do you guys think that's worth
> it?

If I understand you correctly, you want to suggest to the SMuFL people
that there is a parameter to control the roundness of corners in stems
and the like.  What else would be necessary?

Could you provide images that show the reference (or attachment)
points of the flags?  I think this makes it easier to discuss the
necessary vertical offsets.


    Werner