Re: Printing from WindowXP version of emacs

[Peter Dyballa]

Am 17.12.2005 um 22:25 schrieb Lennart Borgman:

> It looks to me that the printing interface in CUPS is different from 
> that normally used by GUI applications in Windows.

Please beware, Lennart! CUPS is the mechanism that takes takes items 
from the printer queue(s) and transfers them to the right printer.

The print dialog is separated from this. It's almost nothing (lpr 
-Pprinter_queue_name file), or it's an application from OpenWindows, 
CDE, KDE, Gnome, or Aqua on Mac OS X. Usually UNIX programmes use the 
programmatic interface to put something into the spool area, i.e. the 
printer queue. Usually the programme should not need to take care what 
kind of file type this data is. CUPS will recognise this and use means 
to convert the data into a form compatible to the printer's needs -- or 
it fails and raises a message, or the printer fails and CUPS raises 
that message. CUPS can be compared to GDI. CUPS is almost independent 
from what a printer manufacturer delivers, because it uses ISO 
standards (PostScript, PDF -- text is wrapped into PS code, graphics 
too). It needs a PPD file. It tells all about the printer -- accept how 
much RAM it actually has, or which fonts are in the extension 
cartridge. These values can be asked from the printer in PostScript. Or 
a manufacturer delivers a module for the printer GUI that allows the 
user to access the printer and configure things (have you seen HP Web 
JetAdmin? This one is only SNMP based). Since CUPS delivers standards 
to the printers, the programmes usually spool standard data too. 
Filters are needed sometimes, to convert text to PS, or to wrap a 
graphics format into an envelope that allows the printer to print it. 
Ghostscript and GIMP-Print are used to convert text or graphics into 
ESC/P or such proprietary formats. In Linux you have some projects that 
write code for these, LPRng for example, or Gnome Print. (CUPS is 
something like TCP/IP in Internet. Above this level you have useful 
"applications" like FTP or HTTP, or print dialogs.)

The problem is that M$ is always making things badder then they find 
them somewhere else. And once you've discovered a way to use Losedows 
means, next release changes this. It becomes documented at the n+1st 
release. Approximately ...

Now, honestly, in UNIX (*BSD, Linux, Solaris, ...) there are no proper 
print job GUIs. They are in the windowing systems used. And so they're 
probably different every time ... But since GNU Emacs supports 
different outfits and file systems and codings and scripts it should be 
able to support different access to different print job GUIs.

I am no expert too, I think, I just had often to install and to fix 
many things.

--
Greetings

  Pete

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