Re: New articulation character for half-open hi-hats?

[Carsten Steger]

>>> This might cause problems if images are converted to, say, cropped
>>> PNG images.  You must assure somehow that the slash won't get cut
>>> off.
>>
>> [...] Furthermore, if I understand your comment correctly, even
>> something like the coda or snappizzicato characters could have the
>> semi-circles that extend beyond the bounding box cut off.  [...]
>
> Perhaps I'm wrong, and the whole thing is a non-issue: ghostscript can
> compute the exact bounding box of an EPS file, AFAIK, taking care of
> the real dimensions of all glyphs (relying on the outlines instead of
> the metrics).

I don't know what ghostscript can do, but even if it cannot compute
the bounding box by considering the real glyph dimensions, this
functionality could be simulated by enlarging the boundary of the EPS
file by a suitable "safety" margin and then calling pnmcrop after the
EPS file has been converted into an image.

> However, I think this is not yet correctly implemented
> in lilypond's EPS->PNG routines since I still see cutoffs in PNG
> images, for example the digit 2 in the second image in section 5.2.3
> of the notation reference.  A really severe cut off is given in the
> snippet file
>
>  using-the--tweak-command-to-tweak-individual-grobs.ly
>
> (this is wrong even in the EPS).
>
> And the cutoffs in section 1.1.3, subsection `Automatic Accidentals',
> look like a real bug in lilypond since this must not happen IMHO...

Based on our discussion, my impression is that the cutoff issue is a
more fundamental issue that affects many more characters (among the
articulation characters at least, for example, downprall, downmordent,
and prallup) than the halfopen articulation character I have designed.
 Therefore, it seems to me that it should be solved at a more
fundamental level.  One solution would be to rethink the strategy for
choosing the bounding boxes of all the glyphs in the LilyPond fonts.
I believe this would not work in general, however, since the user may
choose fonts over which the development team of LilyPond has no
control, and it is fairly common for such fonts to include characters
that extend beyond the borders of the bounding box, e.g., for italic
or slanted characters.  Therefore, it seems to me that the best
strategy would be to modify LilyPond's strategy to convert the music
to cropped PNG images, should there be a problem.

Also, from our discussion it would appear to me that the patch for the
halfopen articulation character I have designed could be pushed.
Would you agree?

Cheers, Carsten