[texhax] TFM format question

Doug McKenna doug at mathemaesthetics.com
Wed Apr 20 21:21:32 CEST 2011

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

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 >= 

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 

Doug McKenna

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