Behaviour of \latinfamily

[Rebecca and Rowland]

>Rebecca and Rowland wrote:
>
[snip]

>Slantfont is a standard TeX font parameter (explained in one of the
>TeXbook appendices if I remember rightly), the only difference with the
>fontinst version is that it's measured in AFM units (ie 1000:1).  It's
>measured as forward slant, as a fraction of height, so 167 = 16.7%
>forward slant, ie in a 10pt font the letters stick out to the right by
>1.67pt.

I see - thanks.  It's appendix F, by the way.

>> Righto - can you give me an idea where I might find the v1.509 docs?
>
>I'll attatch the v1.509 PS file.

Got it; thanks.  And MacGS View managed to render and print it without
crashing.

[snip useful confirmations]

>> Erm...  Is what happens if you're using \latinfamily?  Or if you're not
>> using \latinfamily?  Can you give an example of what you mean?
>
>Yes, this is what \latinfamily does.  If you say
>
>   \latinfamily{ptmx}{}
>
>then \latinfamily is defined:
>
> \def\latinfamily#1#2{{
>   \edef\temp_command{#1}
>   \expandafter\parse_family\temp_command
>      \empty_command\empty_command\end_parse_family
>   \installfonts
>      \installfamily{T1}{#1}{#2}
>      \installfamily{OT1}{#1}{#2}
>      \if_file_exists{ \raw_encoding.mtx }\then
>         \installfamily{\raw_encoding}{#1}{#2}
>      \fi
>      \latin_weights
>   \endinstallfonts
>}}
>
>so what happens is:
>
>   \edef\temp_command{ptmx}
>
>defines \temp_command |-> ptmx
>
>   \expandafter\parse_family\temp_command
>      \empty_command\empty_command\end_parse_family
>
>expands to:
>
>   \parse_family ptmx
>      \empty_command\empty_command\end_parse_family
>
>(this trickery is necessary in case anyone does something like
>\def\foo{ptmx}\latinfamily{\foo}{}).

Bleh.  No wonder I couldn't make any sense out of it.

>Now we call \parse_family which is defined:
>
>\def\parse_family #1#2#3#4#5\end_parse_family{
>   \edef\font_family{#1#2#3}
>   \edef\font_variant{#4#5}
>   \edef\raw_variant{#4#5}
>   \edef\latex_family{#1#2#3#4#5}
>   \ifx#4x
>      ...expert stuff...
>   \else
>      ...non-expert stuff...
>   \fi
>}
>
>so the parameters get matched:
>
>   #1 = p
>   #2 = t
>   #3 = m
>   #4 = x
>   #5 = \empty_command\empty_command
>
>so after the \edef's we get:
>
>   \font_family  |-> ptm
>   \font_variant |-> x
>   \raw_variant  |-> x
>   \latex_family |-> ptmx
>
>and since #4 is `x' the ...expert stuff... is executed.
>
>Oh what fun...

Isn't it just?  Thanks for this.  One question: I take it that the
\latex_family parameter is what's used to build the fd file, so this
example will produce an fd file called OT1ptmx.fd (or T1ptmx.fd)?  What job
to \font_variant and \raw_variant do?

Ta muchly
Rowland.