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From: meb4074@cec1.wustl.edu (Mark Edward Bradley)
Newsgroups: comp.sys.mac.programmer
Subject: Low level printer driver calls
Message-ID: <1989Dec8.040721.28042@cec1.wustl.edu>
Date: 8 Dec 89 04:07:21 GMT
Sender: news@cec2 (USENET News System)
Distribution: na
Organization: Washington University, St. Louis MO
Lines: 45


   If anyone is familiar with low-level printer driver calls, I would appreciate
some advice. I am using the access routines described in Inside Mac II, chapter
5. I am trying to output a bitmap to the printer, with dubious success. My code
follows: (I am programming in assembly language. Sorry, C gods, I'm a new boy)

          _PrDrvrOpen                   ; Open the driver
          move.w      #iPrDevCtl,-(SP)  ; Printer control code
          move.l      #lPrReset,-(SP)   ; Reset printer code
          move.l      #0,-(SP)          ; Unused
          move.l      #0,-(SP)
          _PrCtlCall                    ; Call the driver routine
          move.w      #iPrBitsCtl,-(SP) ; Bit map printing code
          move.l      MyWindPtr,-(SP)   ; Window pointer
          addq.l      #2,(SP)           ; Set pointer on stack to the portBits
          pea         MyRect            ; Enclosing rectangle
          move.l      #lPaintBits,-(SP) ; Use square pixels
          _PrCtlCall
          move.w      #iPrDevCtl,-(SP)
          move.l      #lPrPageEnd,-(SP) ; End page code
          move.l      #0,-(SP)
          move.l      #0,-(SP)
          _PrCtlCall
          _PrDrvrClose                  ; Close the driver

     The first time this routine executes, everything works. Any time after
that, the code executes (I checked w/ MacsBug), but the printer doesn't respond.
When I go to the Chooser, the printer is no longer selected. After re-selecting,
exiting, and re-entering, it still is not selected. When I exit my program, the
system crashes, but not always immediately. And when I reboot, the printer will
form feed without prompting at some point. (Seems to happen during window
operations?)
     Very little of the code above is my own. It's almost verbatim from IM.
I don't know what I'm missing. If you know what might be the problem or if I'm
leaving something out, please e-mail. I'm using a Mac SE with 2MB, no special
hardware, an AppleTalk Imagewriter and an AppleTalk ImageWriter LQ. I'm also
using the Consulair Development System.

Profuse thanks,
           Mark

-------------------------------------------------------------------------------
"Come to .test,    |        meb4074@cec1.wustl.edu        |  "I'm brave!
 the land without  |         Mark Edward Bradley          |   But I'm careful."
 flames!"          |             Markie B.!!              |     -- Goofy