I made two copies of luatex-fonts-demo-vf-1.lua named
vf-a.lua and vf-b.lua
(The original file can be found in
\context-minimals\context\tex\texmf-context\tex\generic\context).
In both copies I changed the three fonts the virtual font uses as
basis to "Arial".
In vf-b.lua I added after the for-loop which manipulates the
caracters this code:
f1.characters[98].width=3000000
f2.characters[98].width=3000000
f3.characters[98].width=3000000
f1.characters[97]= nil
f2.characters[97]= nil
f3.characters[97]= nil
It has the expected effect when I use vf-b: It enlarges the width of
the "b" and removes the "a" from the font.
But it not only affect the vf-b-font, it also affects vf-a: If I
load vf-a *after* vf-b, it also loose the "a" and the width of "b"
is changed.
In a older version of context, where the lua used
"fonts.tfm.readanddefine" instead of the new
"fonts.constructors.readanddefine" I got an side effect too, but
only on the "a".
My questions are
1. Why do I get the side effect only when f1, f2 and f3 call the
same font? Chance (because of the math random) or something else?
2. How can I make a virtual lua-font which is free of such side
effects?
3. I got errors when I tried to use the old version of the virtual
font with the newest context. Is "fonts.tfm.readanddefine" now
deprecated?
--
Ulrike Fischer
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