Re: [Gimp-print-devel] Bad page offset with 4.1.99a2, A4 paper, escp2-480

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

   Date: Fri, 3 Aug 2001 14:32:46 +0100
   From: Julian Bradfield <jc...@dc...>
   cc: gim...@li...

   >   ~/local/gs6.50/bin/gs -sPAPERSIZE=a4 -sDEVICE=stp -sModel=escp2-480 -r360 -dColor=0 -sOutputFile=/dev/lp0 /tmp/4297.ps
   >
   >   Specifically, the page is printed about 21mm too low on the paper.

   >Yes; the current CVS repository (which will be either A3 or B1)
   >supposedly fixes this.

   It doesn't; the page is now 10.5mm too low instead of 21mm too low.
   Diffing a2 against the CVS points me to a line that I was actually
   suspicious about before: in gdevstp-escp2.c, around line 3520,
   we have

10.5 and 21 mm too low in color, or mono?  From what you say below, it
sounds like those numbers are in monochrome (or grayscale).  That
makes sense.  The correct value for max_head_offset in monochrome is 0.

     /*
      * Factor of 2 divisor determined by Jason Pearce.  Need to understand
      * why theoretically.
      */
     top += max_head_offset * nozzle_separation * (72 / 2) / ydpi;

   which in a2 had just 72 / ydpi .

   If I delete this line altogether, I get the expected result in mono.
   In colour (-dColor=1), the page is still too low, but by about 8mm.

In color mode, how far off is it:

1) With this line completely removed?

2) With (72 / 2) / ydpi?

3) With 72 / ydpi?

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

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Member of the League for Programming Freedom -- mail lp...@uu...
Project lead for Gimp Print/stp --  http://gimp-print.sourceforge.net

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