[XeTeX] c.t.t. post re: \mag

[Bruno Voisin]

Le 19 févr. 08 à 15:12, Andreas Matthias a écrit :

> I just spotted that the left and top margins (the origin of TeX's
> coordinate system) are not scaled by \mag. This is in contrast to
> pdftex. I'm not sure which one is correct. But the way pdftex does
> seems more intuitive.
>
> \mag=2000
> \pdfpagewidth=210mm
> \pdfpageheight=297mm
> [...]

That might be linked with the odd initialization of pdfTeX: normally  
pdfTeX is supposed to be initialized according to pdftexconfig.tex (on  
the Mac /usr/local/texlive/2007/texmf-config/tex/generic/config/ 
pdftexconfig.tex) which not only sets \pdfpagewidth and \pdfpageheight  
in true units:

> \pdfpagewidth=210 true mm
> \pdfpageheight=297 true mm

but also sets the left and top margins in true units:

> \pdfhorigin=1 true in
> \pdfvorigin=1 true in

Accordingly, the left and top margins should normally not be scaled by  
\mag.

However, owing to some design decisions of the pdfTeX developers (see  
the explanations by Hartmut Henkel at <http://tug.org/pipermail/macostex-archives/2004-December/012146.html 
 >), the fact that these are true units is not taken into account when  
building the pdfTeX format. I found it confusing when first meeting  
this behaviour in 2004, and still find it confusing now.

Bruno Voisin