[Gambas-user] Ask About POS Programming using Gambas

[nando]

Here is a suggestion and is what I do: (I use ver 1.17)

Make a TIMER which is only for printing to the printer.
It is set for 1 second and all it does is try to print
chars to the printer.  When an error condition comes up,
it won't print until the next second. Works ok for me.

I have a global String var called 'pr'.  This is what is sent
to the printer.

Anywhere in any class at anytime, I can do something like
pr &= "This is a new line & cr & lf
when the timer fires, it tries to print some chars
example something like...(not syntatically correct shown here)


Sub Timer(OPTIONAL s)  'I can pass string 's' in to
                       'add to 'pr' and attempt print immediately

  DIM a AS STRING

  if len(s)>0 then pr &=s    'append optional s to pr
  if len(pr) = 0 then return 'pr has nothing..just exit

  'try to print some chars

  'TRY open...I have my printer open always from program start
  if ERROR=0 then
    while len(pr)>0 AND ERROR=0
      a = left$(pr,20)         'I try printing 20 chars at a time
      TRY WRITE #hfile, a, len(a)
      if error=0 then          'no error, reduce pr
        pr=right$(pr,len(pr)-len(a)
      endif
    wend
  endif  

  ERROR.clear
  'TRY close

end sub


---------- Original Message -----------
From: jose julio vidal <jj at ...1636...>
To: mailing list for gambas users <gambas-user at lists.sourceforge.net>
Sent: Thu, 08 Jan 2009 22:22:19 +0100
Subject: Re: [Gambas-user] Ask About POS Programming using Gambas

> Hi!
> 
> my code:
> 
>   ....
>   DIM hFile AS File
>   DIM txt AS String
>   txt=Chr$(&H1B) & "m" & Chr$(49) & Chr$(0) 'corte papel parcial
>   TRY hFile = OPEN "/dev/lp0" FOR WRITE
>   WRITE #hfile, txt 
>   IF ERROR THEN 
>     message.Error("No se puede acceder a la Impresora")
>   ELSE 
>   END IF
>   ....
> 
> regards
> 
> El jue, 08-01-2009 a las 13:02 +0800, Leo Sendra escribió:
> > Hi all,
> > 
> > I have a problem with my POS program. I have printed a receipt through /dev/lp0. It works.
> > But, when I want to execute a cut paper command, an error occurs. It says that
/dev/lp0 is busy.
> > I know that the printer is still printing when I execute a cut paper command.
> > So, how to handle this error?
> > I think, the solution is I have to execute a cut paper command after the printer stop
printing. But, I don't understand the code.
> > 
> > So, how the codes??? Help me please...
> > 
> > 
> > Thanks for your help...
> > 
> > 
> > 
> >       Berbagi foto Flickr dengan teman di dalam Messenger. Jelajahi Yahoo! Messenger
yang serba baru sekarang! http://id.messenger.yahoo.com
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------- End of Original Message -------