I found this post on stackoverflow where someone was trying to use some
old postscript code from the internet and it wasn't quite doing what he
wanted due to portability issues in the code.

I'm busy with finals week in school so I can't put in the time to work
on it. But if anyone is looking for a (light) PS programming effort,
I the results will be entertaining for the group.

SO question: https://stackoverflow.com/q/59950318/733077/why-does-this-postscript-ps-file-create-way-more-top-margin-than-specified


%!
%
% From: Jonathan Monsarrat (jgm@cs.brown.edu)
% Subject: PostScript -> ASCII *and* ASCII -> PostScript programs
% Newsgroups: comp.lang.postscript
% Date: 1992-10-01 04:45:38 PST
%
% "If anyone is interested, here is an interesting program written by
% Professor John Hughes here at Brown University that formats ASCII
% in PostScript without a machine generator of any kind."
%
%%%
%%% Plan:
%%% Start with an empty string.
%%% For each character in the input stream,
%%% check to see if it's a carriage return.
%%% if so, show the current string and reset it to empty
%%% if not, add it to the current string.

/Courier findfont 10 scalefont setfont %% Choose a fixed width font /lineheight
currentfont /FontBBox get dup %% bbox bbox
0 2 getinterval %% bbox {xm ym}
exch %% {xm ym} bbox
2 2 getinterval %% {xm ym} {xM yM}
aload pop %% {xm ym} xM yM
3 2 roll %% xM yM {xm ym}
aload pop
currentfont /FontMatrix get %% xM yM xm ym MAT
transform %% xM yM xm' ym'
4 2 roll
currentfont /FontMatrix get %% xm' ym' xM yM MAT
transform %% xm' ym' xM' yM'
exch pop %% xm' ym' yM'
sub %% xm' ym'-yM'
exch pop %% dy
neg def

lineheight pstack pop

/str 500 string def %% Room to store a long string...
/empty 500 string def %% An empty string to work with
/stringindex 0 def %% How far we've filled the string
/inch {72 mul } def %% A useful tool...
/pageheight 11 inch def
/topmargin 1 inch def
/botmargin 1 inch def
/leftmargin 1 inch def
/linesperpage pageheight topmargin sub botmargin sub lineheight div cvi def /linenumber 1 def %% the line we're about to write on

/newline { %% move to a new line; flush page if necessary
linenumber linesperpage gt {/linenumber 1 def showpage } if
leftmargin pageheight topmargin sub linenumber lineheight mul sub moveto
/linenumber linenumber 1 add def
} def

/cleanup { %% print out the last bit of whatever you had there...
str show showpage
} def

/startstring { %% empty the string and reset its counter.
str 0 empty putinterval
/stringindex 0 def
} def

/showstring { %% print the string on a new line and flush it
newline
str show
startstring
} def

pstack

/addtostring { %% put another character in the string, if there's room
dup 500 gt {pop}{str exch stringindex exch put
/stringindex stringindex 1 add def} ifelse
} def

%
% Main program: get characters and deal with them
%
{
currentfile read {}{cleanup exit} ifelse
dup 10 eq %% if it's a carriage return...
{pop showstring} %% write out this line of text and start over
{dup 0 eq %% if it's an end-of-file mark...
{exit} %% stop!
{addtostring} %% otherwise, add the character to current string
ifelse}
ifelse %% Sample data follows.
} loop

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Tuesday, May 12, 2020 at 4:34:26 PM UTC-5, luser droog wrote:

I found this post on stackoverflow where someone was trying to use some
old postscript code from the internet and it wasn't quite doing what he wanted due to portability issues in the code.

I'm busy with finals week in school so I can't put in the time to work
on it. But if anyone is looking for a (light) PS programming effort,
I the results will be entertaining for the group.

SO question: https://stackoverflow.com/q/59950318/733077/why-does-this-postscript-ps-file-create-way-more-top-margin-than-specified

%!
%
% From: Jonathan Monsarrat (jgm@cs.brown.edu)
% Subject: PostScript -> ASCII *and* ASCII -> PostScript programs
% Newsgroups: comp.lang.postscript
% Date: 1992-10-01 04:45:38 PST
%
% "If anyone is interested, here is an interesting program written by
% Professor John Hughes here at Brown University that formats ASCII
% in PostScript without a machine generator of any kind."
%
%%%
%%% Plan:
%%% Start with an empty string.
%%% For each character in the input stream,
%%% check to see if it's a carriage return.
%%% if so, show the current string and reset it to empty
%%% if not, add it to the current string.

I got both my finals turned in, so I looked closer at this code.
It's actually pretty decent overall. I did not make a lot of changes.
Changed some names, factored out the ++ operation, simplify calculation
of the leading (nee lineheight). And most importantly replace the
explicit
/pageheight 11 inch def
with your choice between taking the maximum Y value from the page device
or the clipping path.

The bizarre "dup 500 gt" I left alone. I can't see that it hurts anything,
but I can't imagine a situation where it would accomplish anything either.

Modified version:


/Courier 10 selectfont
/leading gsave
currentfont
dup /FontMatrix get matrix currentmatrix matrix invertmatrix concat concat
/FontBBox get aload pop % llx lly urx ury
dtransform 3 2 roll dtransform % urx' ury' llx' lly'
exch pop sub exch pop % ury-lly
grestore def

/buf 500 string def
/empty 500 string def
/ptr 0 def
/inch {72 mul} def
/pageheight currentpagedevice /PageSize get 1 get def
%/pageheight newpath clippath pathbbox 4 1 roll pop pop pop def
/topmargin 1 inch def
/botmargin 1 inch def
/leftmargin 1 inch def
/linesperpage pageheight topmargin sub botmargin sub leading div cvi def /linenumber 1 def % the line we're about to write on
/++ {dup load 1 add store} def

/newline {
linenumber linesperpage gt {/linenumber 1 def showpage} if
leftmargin pageheight topmargin sub linenumber leading mul sub moveto
/linenumber ++
} def

/cleanup {
buf show showpage
} def

/startstring {
buf 0 empty putinterval
/ptr 0 def
} def

/showstring {
newline
buf show
startstring
} def

/addtostring {
dup 500 gt {pop}{
buf exch ptr exch put
/ptr ++
} ifelse
} def

{
currentfile read {}{cleanup exit} ifelse
dup 10 eq
{pop showstring}
{dup 0 eq
{exit}
{addtostring}
ifelse
}
ifelse
} loop

Show me the money!

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

In article <dfbf4f4d-4b1b-4acb-8b4e-362cc46fc8cc@googlegroups.com>, luser.droog@gmail.com says...

The bizarre "dup 500 gt" I left alone. I can't see that it hurts

anything,

but I can't imagine a situation where it would accomplish anything either.

I haven't read the code i detail, but surely that is simply preventing
an overflow of the string, which is defined as a 500 element object ?

Though I agree it would have to be a very small point size and large
media width to fit more than 500 characters across it.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Thursday, May 14, 2020 at 1:53:32 AM UTC-5, ken wrote:

In article <dfbf4f4d-4b1b-4acb-8b4e-362cc46fc8cc@googlegroups.com>, luser.droog@gmail.com says...

The bizarre "dup 500 gt" I left alone. I can't see that it hurts

anything,

but I can't imagine a situation where it would accomplish anything either.

I haven't read the code i detail, but surely that is simply preventing
an overflow of the string, which is defined as a 500 element object ?

Though I agree it would have to be a very small point size and large
media width to fit more than 500 characters across it.

That's what I thought at first, but no it's comparing the character value
that just came from `read`. It probably would be a good idea to check the capacity of the string there. The code also expects an EOF indication to
happen by `read` returning a 0.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Wednesday, May 13, 2020 at 7:34:54 PM UTC-5, luser droog wrote:

On Tuesday, May 12, 2020 at 4:34:26 PM UTC-5, luser droog wrote:

I found this post on stackoverflow where someone was trying to use some
old postscript code from the internet and it wasn't quite doing what he wanted due to portability issues in the code.

I'm busy with finals week in school so I can't put in the time to work
on it. But if anyone is looking for a (light) PS programming effort,
I the results will be entertaining for the group.

SO question: https://stackoverflow.com/q/59950318/733077/why-does-this-postscript-ps-file-create-way-more-top-margin-than-specified

%!
%
% From: Jonathan Monsarrat (jgm@cs.brown.edu)
% Subject: PostScript -> ASCII *and* ASCII -> PostScript programs
% Newsgroups: comp.lang.postscript
% Date: 1992-10-01 04:45:38 PST
%
% "If anyone is interested, here is an interesting program written by
% Professor John Hughes here at Brown University that formats ASCII
% in PostScript without a machine generator of any kind."
%
%%%
%%% Plan:
%%% Start with an empty string.
%%% For each character in the input stream,
%%% check to see if it's a carriage return.
%%% if so, show the current string and reset it to empty
%%% if not, add it to the current string.

I got both my finals turned in, so I looked closer at this code.
It's actually pretty decent overall. I did not make a lot of changes.
Changed some names, factored out the ++ operation, simplify calculation
of the leading (nee lineheight). And most importantly replace the
explicit
/pageheight 11 inch def
with your choice between taking the maximum Y value from the page device
or the clipping path.

The bizarre "dup 500 gt" I left alone. I can't see that it hurts anything, but I can't imagine a situation where it would accomplish anything either.

Modified version:

I did some more editing. I wrapped all the main line code in procedures so
the top level structure is very simple:

<< ... /main { initialize mainloop } ... >> begin main

I teased out all the definitions which are sensible to modify and put them
in a procedure called /parameters which is right at the top.

I think this makes the program easier to scan and read. You no longer need
to slog through all that initialization code to see what's being
initialized. And then I squeezed all the short procedures into one-liners
to make the whole thing shorter overall.

New modified version:


<< % wrap everything in a dictionary

/parameters { % user modifiable
/buflength 500 def
/topmargin 1 inch def
/botmargin 1 inch def
/leftmargin 1 inch def
/Courier 10 selectfont
}

/main { initialize mainloop }

/initialize {

parameters

/leading gsave
currentfont
dup /FontMatrix get matrix currentmatrix matrix invertmatrix concat concat
/FontBBox get aload pop % llx lly urx ury
dtransform 3 2 roll dtransform % urx' ury' llx' lly'
exch pop sub exch pop % ury-lly
grestore def

/buf buflength string def
/empty buflength string def
/ptr 0 def

/pageheight currentpagedevice /PageSize get 1 get def
%/pageheight newpath clippath pathbbox 4 1 roll pop pop pop def
/linesperpage pageheight topmargin sub botmargin sub leading div cvi def
/linenumber 1 def % the line we're about to write on
}

/mainloop {
{
currentfile read {}{cleanup exit} ifelse
dup 10 eq {
pop showstring
}{
addtostring %dup 0 eq {exit}{addtostring} ifelse
} ifelse
} loop
}

/newline {
linenumber linesperpage gt {/linenumber 1 def showpage} if
leftmargin pageheight topmargin sub linenumber leading mul sub moveto
/linenumber ++
}

/cleanup { linenumber 1 gt { buf show showpage } if }
/startstring { buf 0 empty putinterval /ptr 0 def }
/showstring { newline buf show startstring }
/addtostring { ptr buf length ge {pop}{ buf exch ptr exch put /ptr ++ } ifelse }

/inch {72 mul}
/++ {dup load 1 add store}

begin main

Text immediately following will be printed on the output device.
Use explicit newlines to trigger carriage returns.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)