Handle newly encountered cases in BDF files.

[MattHeffron]

Better handling of a glyph with ENCODING of -1. (From Monaco-10.bdf converted mac font)
I treat it as the slug glyph, instead of the default of a solid block.
This addresses issue: #2014
None of my test cases had that any glyph with that ENCODING.

This same bdf file also caused corrupted bitmap glyphs due to glyphs with zero width bitmap and zero advance (escapement). This has been corrected in a separate commit.

[pamoroso]

On Linux Mint 22.1 Cinnamon I tested the changes up to edcc0e3 and now BDF:WRITE-BDF-TO-DISPLAYFONT-FILES processes the Commodore 64 font with no errors.

But how can I determine the name of the converted font to feed to the TEdit charlooks menu? I added the directory with the new font to DISPLAYFONTDIRECTORIES but entering c64, c64d, c6416, c6416-mrr, or anything else in the Other field of TEdit's charlooks menu yields Can't find OTHER font c6416-mrr.

[MattHeffron]

But how can I determine the name of the converted font to feed to the TEdit charlooks menu? I added the directory with the new font to DISPLAYFONTDIRECTORIES but entering c64, c64d, c6416, c6416-mrr, or anything else in the Other field of TEdit's charlooks menu yields Can't find OTHER font c6416-mrr.

This appears to be due to the way that font files are named.
Since there is no punctuation between the FAMILY and the SIZE in the file name (e.g. C6416 when FAMILY = C64 and SIZE = 16), calls to FONTSAVAILABLE will fail to report the font. (Internally, it does everything in UPPERCASE.)
It does find the file, then it takes apart that filename and checks that the pieces match the original FAMILY, SIZE, etc. original arguments. It takes the first character that is a digit as the beginning of the size. So, for c6416 it splits it to FAMILY = C and SIZE = 6416. The FAMILY doesn't match the C64 it was expecting, so it rejects the match.

Interestingly, calling (FONTCREATE 'C64 16) works correctly.
And, after creating that, FONTSAVAILABLE does succeed, as does using "Other" in TEDIT.

So, what should BDF:WRITE-BDF-TO-DISPLAYFONT-FILES do if the FAMILY argument provided, or internally determined FAMILY, contain any digits?

[nbriggs]

I don’t think it should do anything different, but the documentation should say “don’t name fonts with names that end in digits”