Re: [9fans] p9p troff/ps problem, comparison with heirloom

[Rudolf Sykora <rudolf.sykora@gmail.com>]

On 11 November 2011 20:06, Rudolf Sykora <rudolf.sykora@gmail.com> wrote:
> On 11 November 2011 19:38, Rudolf Sykora <rudolf.sykora@gmail.com> wrote:
>
>> Further, when I take the directory /sys/lib/postscript/font from plan9
>> and copy it to (replace with it) the contents of p9p's
>> $PLAN9/postscript/font I get a result quite similar to the previously
>> shown output of the heirloom suite, i.e., everything is present,
>> however the square-root sign is wrongly placed.
>
> The story is more complicated... :(
>
> Even though I see some placement on screen (in gv or page) I get a
> different result when printed. E.g., the on screen wrongly placed sqrt
> sign gets printed ok, while one of the big brackets though good on
> screen prints wrongly. Furthermore, now page displays different things
> than gv.
>
> I hoped that with postscript one can achieve the same results
> everywhere, but it actually seems difficult...
>
> Ruda
>

It seems that quite a few problems I've been having are connected with
the lines which both dpost on plan9 or tr2post on p9p add to the
by-them created postscript. I find there lines like this:
-----------------------------
%
% A few arrays used to adjust reference points and character widths in some
% of the printer resident fonts. If square roots are too high try changing
% the lines describing /radical and /radicalex to,
%
%	/radical	[0 -75 550 0]
%	/radicalex	[-50 -75 500 0]
%
% Move braceleftbt a bit - default PostScript character is off a bit.
%

/Sdefs [
	/bracketlefttp		[201 500]
	/bracketleftbt		[201 500]
	/bracketrighttp		[-81 380]
	/bracketrightbt		[-83 380]
	/braceleftbt		[203 490]
	/bracketrightex		[220 -125 500 0]
	/radical		[0 0 550 0]
	/radicalex		[-50 0 500 0]
	/parenleftex		[-20 -170 0 0]
	/integral		[100 -50 500 0]
	/infinity		[10 -75 730 0]
] def

/S1defs [
	/underscore		[0 80 500 0]
	/endash			[7 90 650 0]
] def
-----------------------------

Apparently, somebody has tried to fine-tune placement of certain
characters. E.g., the bottom part of a left brace (/braceleftbt) seems
shifted by 2 points. Writing 201 500 into the relevant bracket solves
my problem with a broken left bracket...

This tuning can also stand behind the difference I see on the screen
and when the file is printed by a printer. Perhaps programs like gv
don't read these shifts and what they show is then different from what
gets printed.

Also it might explain why boxes' upper bars are not printed in their
due place, at least for me.

Ruda