[python-win32] Virtual print driver - similiar to winpdf

[Mike Driscoll]

geoff wrote:
> Thanks for you guidance Tim.  After reviewing I am coming to the same
> conclusion.
>
>   
>> This is trickier than you might guess.  Does the application actually
>> write to the printer using a Windows printer driver?  Some old
>> applications that just used a printer for logging wrote directly to the
>> parallel ports.  That kind of thing is almost impossible to trap.  If it
>> does, how does it pick the printer?
>>     
>
> The application is quite "configurable".  Printers can be configured
> so the application to write to either a port (including UNC path), a
> Windows print driver or directly to a file that is specificed within
> the application.  We typically use the "generic/text" driver to
> define the "windows" printers, however, just pointing the app to
> "LPT1:" works just fine too.
>
> If it doesn't present you with a
>   
>> dialog, then it might be picking the printer by name.  That means you
>> can't just install your own driver, unless you use the same name.  If it
>> does present you with a dialog, can you use the Generic / Text-Only
>> printer driver, and have it dump to a text file?  (That's one of the
>> standard printer drivers built-in to Windows.)
>>     
>
> I have thought of the Windows printer defined as "file" however, I
> don't want the user to be prompted for the file name each time and
> haven't found a way to suppress this.
>
>   
>> If you really need a driver, you are not going to be able to do this
>> from Python.  There are a sample printer drivers in the WDK (Windows
>> Driver Kit).  It is not a project to be undertaken lightly.
>>     
>
> Yes, I am starting to understand that :-(
>
> What we are trying to do is capture the printing "dynamically" while
> the user is running the application ( -- think of invoice printing in
> a business).  The app output is text, with some printer control codes
> embedded to change fonts, colors, newlines, etc, but other than that
> it is just ascii text printed line-by-line sent to the specificied
> port or file.
>
> The problem we see with the "print to a file" approach is we would
> like the system to react immediately when the user "prints" and having
> some sort of "polling" to watch the file isn't the best solution as it
> introduces a delay/latency.
>
> One option I was considering is using Windows printer defined as a
> "Standard TCP/IP Printer Port".  Our thinking is to manually configure
> a printer in Windows and then use the LPR or RAW method of this print
> monitor to redirect the output to our program via TCP/IP.  Haven't
> tested this , however, the thinking is that this would tell us
> immediately when the user is printing and our utility could re-act
> accordingly.
>
> Any thoughts or comments or guidance would be truly appreciated.
>
> g.
>
>   

You might take a look at Pyla. It's a print to fax library. I think it's 
kind of what you're talking about. I've been trying to hack it off and 
on for a while now as we only need a little of its functionality here at 
work. There isn't much for docs, so you'll have to read the source. 
Here's a link: http://www.teamsw.it/pyla/

Mike