Re: Internal Error (overlap) for some fonts when running make

[James]

On 05/11/2019 12:06, David Kastrup wrote:
> James <address@hidden> writes:
>
> > Hello,
> >
> > Now that Dan has made default make commands 'terser' I am noticing
> > while building our fonts that I see quite a few 'errors' that look
> > like this:
> >
> > Internal Error (overlap) in clefs.petrucci.c5_change: Winding number
> > did not return to 0 when x=25.9951
> > Internal Error (overlap) in clefs.petrucci.c5_change: monotonic is
> > both needed and unneeded
> > (22.1885,310.434)->(25.9951,304.135). x=25.9951 (prev=8.40259)
> >
> > Of course they have 'always' (probably) been there - I don't want to
> > claim anything like a regression.
> >
> > But do we need to care?
> The first is pretty typical for Metafont/Metapost fonts, affecting
> cusps.  The latter looks like there might be a logic error in the
> programming for a variable called "monotonic".  Fixing those kinds of
> bugs would improve confidence in the font creation instructions, but the
> real test is whether people complain about the look of the resulting
> character.
Well I see that fontforge has the ability to 'fix' a font using whatever 
clever automatic means it has been programmed with via it's own 
interface. I was going to just 'blast' the fonts with this 'automatic 
fixing' purely for my own curiosity than an actual 'considered' patch :) 
but when I tried to point the interface to 'fonts' inside my 
lilypond_git repo, it said it could not find any - because I hadn't 
built them I guess (see how I don't know what I am doing?!). While I am 
sure Werner et al are rolling their eyes and shaking their heads, I 
wondered if it is possible to take a built font and 'fix' it and then 
get the code of it back into my git repo to make a diff/patch for my 
curiosity, but it wasn't immediately obvious how I'd do that.

I am sure my time could be better spent but this is what keeps me 
interested in helping with a piece of software I don't actually use 
anymore :D but being more interested in the internals of maintaining and 
patching/fixing a large piece of codebase.

James