[texhax] Redefining default font sizes

[Uwe Lueck]

 On  28 Mar, 2011, at 18:33, Mike B. wrote:
> Is it possible to scale only the fonts? the document is already an A4 size. 
> So if the class file defines \normalsize as font size of say, 8pt, 
> I'd like to change that into say 12pt.

Hopefully the most straightforward answer: 
copy those font size definitions (into the preamble after 
\documentclass) and modify them (within \makeatletter ... 
\makeatother). 

Here is the usual definition of \normalsize in size10.clo 
for the default size setting of article.cls:

\renewcommand\normalsize{%
 \@setfontsize\normalsize\@xpt\@xiipt
 \abovedisplayskip 10\p@ \@plus2\p@ \@minus5\p@
 \abovedisplayshortskip \z@ \@plus3\p@
 \belowdisplayshortskip 6\p@ \@plus3\p@ \@minus3\p@
 \belowdisplayskip \abovedisplayskip
 \let\@listi\@listI}

You might replace the second line with this 
(including Axel's suggestion for leading):

    \@setfontsize\normalsize\@xiipt{20}%

(The comment mark may be important.)
That is, the first argument of the command \@setfontsize 
is the name of the font size command, the second is the 
glyph size, the third is the leading (setting \baselineskip).

\@xiipt stands for 12pt, see the others in your .cls, in 
the "size" files, or ... at least without fix2e, it may be good 
to use them instead of using explicit number/unit pairs. 

See also these earlier postings:

	http://tug.org/pipermail/texhax/2010-July/015362.html
	http://tug.org/pipermail/texhax/2010-July/015360.html

Hope this helps

 -- Uwe.