[tex-k] AFM2TFM: are length values handled correctly? (Again)

Michail Vidiassov master@iaas.msu.ru
Fri, 22 Nov 2002 18:32:20 +0300 (MSK)


Dear All,
In short:
the tfm file afm2tfm produces for adobe Times-Roman font (and other fonts too)
has different character widths then tfm font (ptmr8r.tfm) from CTAN.
Why?

In detail:

in October,  2001 the discussion under the same subject
was started in this list by the following question by Vladimir Volovich:
 Is AFM2TFM taking into account the difference between the size of PS
 and TeX points?
The answer was that the sizes are relative, thus character widths
from afm file are to by copied to tfm without any correction.

BUT as tftopl shows me the tfm files on CTAN have character widths
different from that in afm files.
In the following example CTAN ptmr8r is comapared to afm2tfm generated file,
CTAN char widths are the smaller ones:
 (CHARACTER O 53
-   (CHARWD R 0.56399)
+   (CHARWD R 0.564)
 (CHARACTER O 54
    (CHARWD R 0.25)
 (CHARACTER O 55
-   (CHARWD R 0.332996)
+   (CHARWD R 0.333)
 (CHARACTER O 56
    (CHARWD R 0.25)
 (CHARACTER O 57
-   (CHARWD R 0.27799)
+   (CHARWD R 0.278)
 (CHARACTER C 0
    (CHARWD R 0.5)
...
The commands to generate the example are:
afm2tfm ptmr8a.afm -T 8r.enc ptmr8r_my.tfm
tftopl ptmr8r_my.tfm | egrep "CHARACTER|CHARWD" > ptmr8r_my.cpl
tftopl ptmr8r.tfm    | egrep "CHARACTER|CHARWD" > ptmr8r.cpl
diff -U3 ptmr8r.cpl ptmr8r_my.cpl
                            Sincerely, Michail