Hi Jen,
> I have boiled down my problem to the following short example:
Thanks.
$ cat jen.tr
.PS
#command "\X'ps: exec 0 setlinecap'"
linethick = 2
line right 1
move right 0.5
#command "\X'ps: exec 1 setlinecap'"
line right 2
.PE
$
> The tail of the PostScript file is this:
...
> 2 LW 144 12 72 12 DL 324 12 180 12 DL 0 Cg EP
>
> Now, if I uncomment the first "command" line, I get this PostScript
...
> 72 12 EBEGIN
> 0 setlinecap
> EEND 2 LW 144 24 72 24 DL 324 24 180 24 DL 0 Cg EP
...
> The lines come out fine, but they have shifted down the page a bit.
By the line spacing used for text.
> When I uncomment the second "command" line, 12 gets added again to
> what comes after it, so that the second line appears further down the
> page than the first one:
Another unit of line spacing.
> Does anyone understand what is happening here?
You are putting text lines interpersed with pic's output, they just
happen to not have any text on them.
$ ed jen.tr
137
/exec
#command "\X'ps: exec 0 setlinecap'"
s/#/
command "\X'ps: exec 0 setlinecap'"
s/"$/\\c&
command "\X'ps: exec 0 setlinecap'\c"
w ralph.tr
138
q
$
$ diff jen.tr ralph.tr
2c2
< #command "\X'ps: exec 0 setlinecap'"
---
> command "\X'ps: exec 0 setlinecap'"\c
$
$ diff <(pic <jen.tr) <(pic <ralph.tr)
10a11,12
> .lf 2
> \X'ps: exec 0 setlinecap'\c
$
$ diff <(groff -p <jen.tr) <(groff -p <ralph.tr)
3a4
> %%DocumentNeededResources: font Times-Roman
197c198,199
< grops begin/DEFS 1 dict def DEFS begin/u{.001 mul}bind def end/RES 72
---
> %%IncludeResource: font Times-Roman
> grops begin/DEFS 52 dict def DEFS begin/u{.001 mul}bind def end/RES 72
204c206,208
< 2 LW 144 12 72 12 DL 324 12 180 12 DL 0 Cg EP
---
> 72 12 EBEGIN
> 0 setlinecap
> EEND 2 LW 144 12 72 12 DL 324 12 180 12 DL 0 Cg EP
$
$ # one word per line
$ diff <(groff -p <jen.tr | owpl) <(groff -p <ralph.tr | owpl)
11a12,14
> %%DocumentNeededResources:
> font
> Times-Roman
557a561,563
> %%IncludeResource:
> font
> Times-Roman
560c566
< 1
---
> 52
580a587,592
> 72
> 12
> EBEGIN
> 0
> setlinecap
> EEND
$
The `\X' is still triggering the addition of the Times-Roman font, but
the coordinates that had twelve added before are unaltered. `\c' is
described in section 4.2 of CSTR 54, https://troff.org/54.pdf, and in
the output of `info groff 'Line Control' | cat'.
--
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy
