Re: fontforge-problem?

[tisimst]

Thomas,

On Tue, May 31, 2016 at 2:09 PM, Thomas Morley-2 [via Lilypond] <
address@hidden> wrote:

> I usually don't pay much attention to the log of simple `make`, but
> after our present doc-problems I took a closer look and noticed two
> instances of `Internal Error` here one of it:
>
>
> Invoking "t1asm parmesan-noteheads20.pt1 parmesan-noteheads20.pfb"...
>
> Invoking "/usr/bin/fontforge -script parmesan-noteheads20.pe
> parmesan-noteheads20.pfb"...
> Copyright (c) 2000-2012 by George Williams.
>  Executable based on sources from 14:57 GMT 31-Jul-2012-ML.
>  Library based on sources from 14:57 GMT 31-Jul-2012.
> Internal Error (overlap) in noteheads.uM3neomensural: Mismatched
> intersection.
>  (669,462,430,017)->(650,002,178,75) ends at (-999999,-999999) while
> (650,002,178,75)->(617,499,179,724) starts at (650,002,178,75)
> Internal Error (overlap) in noteheads.uM3neomensural: monotonic is
> both needed and unneeded (630,541,427,486)->(650,821,448,141).
> x=650,001 (prev=624,031)
> Internal Error (overlap) in noteheads.uM3neomensural: Winding number
> did not return to 0 when x=650,001
> Internal Error (overlap) in noteheads.uM3neomensural: monotonic is
> both needed and unneeded (630,541,427,486)->(650,821,448,141).
> x=650,001 (prev=624,031)
> Internal Error (overlap) in noteheads.uM3neomensural: Winding number
> did not return to 0 when x=650,001
> Internal Error (overlap) in noteheads.uM3neomensural: monotonic is
> both needed and unneeded (630,541,427,486)->(650,821,448,141).
> x=650,001 (prev=624,031)
> Internal Error (overlap) in noteheads.uM3neomensural: Winding number
> did not return to 0 when x=650,001
> Internal Error (overlap) in noteheads.uM2neomensural: Mismatched
> intersection.
>  (519,46,430,017)->(500,178,75) ends at (-999999,-999999) while
> (500,178,75)->(467,497,179,724) starts at (500,178,75)
> Internal Error (overlap) in noteheads.uM2neomensural: monotonic is
> both needed and unneeded (480,539,427,486)->(500,819,448,141).
> x=499,999 (prev=474,029)
> Internal Error (overlap) in noteheads.uM2neomensural: Winding number
> did not return to 0 when x=499,999
> Internal Error (overlap) in noteheads.uM2neomensural: monotonic is
> both needed and unneeded (480,539,427,486)->(500,819,448,141).
> x=499,999 (prev=474,029)
> Internal Error (overlap) in noteheads.uM2neomensural: Winding number
> did not return to 0 when x=499,999
> Internal Error (overlap) in noteheads.uM2neomensural: monotonic is
> both needed and unneeded (480,539,427,486)->(500,819,448,141).
> x=499,999 (prev=474,029)
> Internal Error (overlap) in noteheads.uM2neomensural: Winding number
> did not return to 0 when x=499,999
> Internal Error (overlap) in noteheads.urM3neomensural: Mismatched
> intersection.
>  (669,462,430,016)->(650,002,178,75) ends at (-999999,-999999) while
> (650,002,178,75)->(617,499,179,724) starts at (650,002,178,75)
> Internal Error (overlap) in noteheads.urM3neomensural: monotonic is
> both needed and unneeded (630,541,427,486)->(650,821,448,14).
> x=650,001 (prev=624,031)
> Internal Error (overlap) in noteheads.urM3neomensural: Winding number
> did not return to 0 when x=650,001
> Internal Error (overlap) in noteheads.urM3neomensural: monotonic is
> both needed and unneeded (630,541,427,486)->(650,821,448,14).
> x=650,001 (prev=624,031)
> Internal Error (overlap) in noteheads.urM3neomensural: Winding number
> did not return to 0 when x=650,001
> Internal Error (overlap) in noteheads.urM3neomensural: monotonic is
> both needed and unneeded (630,541,427,486)->(650,821,448,14).
> x=650,001 (prev=624,031)
> Internal Error (overlap) in noteheads.urM3neomensural: Winding number
> did not return to 0 when x=650,001
> Internal Error (overlap) in noteheads.urM2neomensural: Mismatched
> intersection.
>  (519,46,430,016)->(500,178,75) ends at (-999999,-999999) while
> (500,178,75)->(467,497,179,724) starts at (500,178,75)
> Internal Error (overlap) in noteheads.urM2neomensural: monotonic is
> both needed and unneeded (480,539,427,486)->(500,819,448,14).
> x=499,999 (prev=474,029)
> Internal Error (overlap) in noteheads.urM2neomensural: Winding number
> did not return to 0 when x=499,999
> Internal Error (overlap) in noteheads.urM2neomensural: monotonic is
> both needed and unneeded (480,539,427,486)->(500,819,448,14).
> x=499,999 (prev=474,029)
> Internal Error (overlap) in noteheads.urM2neomensural: Winding number
> did not return to 0 when x=499,999
> Internal Error (overlap) in noteheads.urM2neomensural: monotonic is
> both needed and unneeded (480,539,427,486)->(500,819,448,14).
> x=499,999 (prev=474,029)
> Internal Error (overlap) in noteheads.urM2neomensural: Winding number
> did not return to 0 when x=499,999
>
> *** Successfully generated parmesan-noteheads20.pfb! ***
>
>
>
> No idea, if this is a real problem, just wanted to let you know.
>

My experience is that this occurs when there are more than two overlapping
shapes. It doesn't necessarily mean a problem with the font. It's just that
FontForge's algorithm to merge overlapping shapes couldn't figure out how
to handle ALL the shapes at the same time. Usually this results in some
shapes being merged successfully while others are left as is. When the font
is actually used, because the shapes are outlined in the correct
directions, there isn't an apparent problem--indeed, it isn't a "problem"
at all. I've seen other fonts use this technique quite successfully. It
also makes it easy to edit at a later time (when done by hand) because the
original, unmerged shapes have been preserved.

Sorry if that isn't clear.

HTH,
Abraham




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