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From: carl@hamlet.caltech.edu (Lydick, Carl)
Newsgroups: comp.lang.postscript
Subject: Re: Obliquing fonts
Summary: Example?
Keywords: Oblique, slant, tan
Message-ID: <1991May23.092143.14619@nntp-server.caltech.edu>
Date: 23 May 91 09:20:28 GMT
References: <24968@well.sf.ca.us>
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Organization: California Institute of Technology
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In article <24968@well.sf.ca.us>, capslock@well.sf.ca.us (Allen Crider) writes...
>I'm trying to oblique a roman font. I know the pointsize and I know the 
>obliquing angle. The only example of obliquing type I have seen is in
>the Blue book (Tutorial and Cookbook) in which they give an example of
>a font obliqued 30 degrees:
> [12 0 6.93 12 0 0] makefont
> "The 6.93 in our last matrix above is the product of 12xtan30, so our
>characters are obliqued by thirty degrees." Says the Blue Book.
> 
>I tried doing this in C:
>f = 12 * tan(30);
> 
>and get 76.864, not 6.93.
>Since I wasn't around when they passed out the trigonometry, maybe some
>kind soul could guide me to the best way to figure out the correct value
>to put in that matrix. Thanks

PostScript uses degrees.  C's tan() uses radians.  Tan(30 degrees) = 1/sqrt(3),
which is, in fact, about 6.93.
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Carl J Lydick	HEPnet/NSI: SOL1::CARL	Internet: CARL@SOL1.GPS.CALTECH.EDU