Re: [Gimp-print-devel] questions

[Robert L K. <rl...@al...>]

   From: sh...@al...
   Date: Sun, 30 Jan 2000 21:19:59 +0900

   One of the first things I noticed was that it generated an unknown command
   error.  gimp-print included an ESC ( K command.  What does this command
   do?  It's not listed in my documentation.  Is there a better document
   that describes this stuff, or, is this an undocumented feature?  Can we
   make a document for undocumented features?

ESC(K sets color vs. black only.  It's not a big deal.

   The other error it generated was a malformed page format error.  The
   page format command ESC ( c should take a 4 byte format string, but
   the one in the file is an 8 byte string.  What does the 8 byte version
   of this command mean?

I don't know.  I'm assuming that it gives 4 bytes for each setting
rather than 2, but we'll have to figure this out.  I got that from
a print output file somebody gave me and my "disassembler".

   I also have some other, more general questions.  There are two ways to send
   raster data to a 750.  Using "ESC i" or "ESC .".   The "." form include
   a density number which lets you know what horizontal DPI the raster
   data should be printed at, but, the "i" version does not.  What determines
   the horizontal printing density for the "i" form?  I assumed that it
   would be a function of the relative horizontal units being used.  This
   probably relates to the page format specification uncertainty I mentioned
   above.  And what exactly are the "page management units" good for?

Page management units are used for the ESC(c command (page format) and
the like.  The doc for the various commands says which unit is used
for each command.  I presume that the horizontal print density for
ESCi comes from the horizontal units (or at any rate, that makes
sense).

In 720 and 1440 dpi mode, I think the right units are 720 dpi for page
management, 1440 for horizontal, and 720 for vertical.  The printer
can't actually do 1440 dpi, though, so that requires two passes with
the carriage shifted by 1 unit for the intermediate dots.  It's also
possible that with ESCi it's automatically running at 720 dpi.  I'll
ask my friend to print something out at 360 dpi.

For the 750, it's really going to be necessary to use ESCi, because
that's the only way to get variable dot size.

-- 
Robert Krawitz <rl...@al...>      http://www.tiac.net/users/rlk/

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lp...@uu...
Project lead for The Gimp Print --  http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton