[texhax] TFM format question

[Doug McKenna]

Reinhard Kotucha wrote -

>These values are calculated automatically when the tfm file is created
>but it seems that they are not used by TeX because characters < 33 are
>accessible.

Do you mean "inaccessible"?

>Maybe you have to look into the sources.  Do you get the same results
>if you convert the TFM file to PL and then back to TFM?  I get:
>
> $ cmp manfnt-1.tfm manfnt.tfm 
> manfnt-1.tfm manfnt.tfm differ: byte 93, line 1
>
>This is the only byte which differs, it's 0x00 in the original file
>and 0x80 in the converted one, but I don't know its meaning.

If I counted correctly, byte 93 is the "seven_bit_safe" flag.  It makes 
sense that it's being set, as there are no character codes in the file >= 
128.

I still don't understand what the consequences are of declaring glyph 
dimensions in a TFM file for a character code outside the internally 
declared [begin_char:end_char] range.  Maybe none (other than wasted 
space).


Doug McKenna