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List:       kde-core-devel
Subject:    Re: Printing in KDE 2.0
From:       Richard Moore <rich () kde ! org>
Date:       2000-05-22 21:30:10
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Waldo Bastian wrote:
> 
> Comments on the following proposal are highly appreciated.

My first thought is that there is a layer missing - I would like the
print
dialog to be able to include functionality like 2 up printing (possibly
simply by using psnup). I think really though this should be part of a
larger piece of code for page handling. For example it should be easy
for an application to handle page numbering and adding headers etc. I
don't know how easy it is to do this in a good way, but I think it
should
be possible.

I'll write some more when I've had more of a think.

Rich.

> 
> Cheers,
> Waldo Bastian
> 
> RFC: Printing in KDE 2.0
> ========================
> Date: May 22, 2000
> Author: Waldo Bastian
> 
> Printing support in KDE has not been changed since KDE 1.1.2. As such
> it is not completely up to spec with the rest of KDE 2.0. In this document
> a printing architecture for KDE 2.0 is proposed.
> 
> Requirements
> ============
> 
> Four different desired printing related abilities can be identified
> within KDE:
> 
> 1) The ability of a user to select a printer from the list of installed
> printers to be used for a print request and to select, possibly
> application specific, options for the print request.
> 
> 2) The ability of a user to be notified of the status of his outstanding
> print requests and the ability for the user to cancel outstanding print
> requests.
> 
> 3) The ability of an application to query the properties of the printer
> used for a certain print request as well as options specified by the user
> for this specific print request.
> 
> 4) The ability of a user to add and configure a printer.
> 
> Status in KDE 1.1.2
> ===================
> 
> Ad 1) QPrintDialog provides this functionality in KDE 1.1.2. The drawbacks
> are that this dialog does not fit in well with the KDE translation meachanism
> and that it is not possible to add application specific options to this
> dialog.
> 
> Ad 2) In KDE 1.1.2 applications exists which provide this functionality. The
> user has to start these applications explicitly. There is no integration
> with the application that issued the print-request.
> 
> Ad 3) The QPrinter class provides basic information about the printer and
> the specific print request, mostly based on information supplied by the user.
> 
> Ad 4) KDE 1.1.2 provides no way to do this.
> 
> Proposed KDE 2.0 printing architecture
> ======================================
> 
> I suggest to adopt sysAPS as API to access the operating systems printing
> system, e.g. CUPS or LPR:
> 
> KDE -> sysAPS -> IPP -> CUPS -> filters -> driver -> backend
>               -> LPR -> filters -> driver -> backend
> 
> Other printing systems can be supported by adding support for them to sysAPS.
> 
> To quote the sysAPS homepage:
> 
> "This project, driven by Corel, provides a unified API for accessing
> printing-specific services outside the realm of the graphics API. This
> includes querying & controlling features of a given printer model, sending
> jobs, accessing queues and configuration."
> 
> sysAPS is under LGPL, is written in C and has both a C as well as an optional
> C++ API. It is a rather young project so it should not be a problem to adapt
> to any specific wishes in the API. You can find them at
> http://sourceforge.net/project/?group_id=2328.
> 
> Based on sysAPS it will be relatively straightforward to meet KDEs printing
> requirements:
> 
> 1) A KPrintDialog based on KDIalogBase should be made. It can use sysAPS
> to query for available printers and enable/disable available options
> based on the capabilities of the selected printer.
> 
> 2) A notification/control interface should be made for printing job-control.
> sysAPS seems to provide all necassery functionality. We only need to provide
> the UI. Maybe this can be part of kio_uiserver. Maybe it should be made a
> seperate application.
> 
> 3) For now the QPrinter class seems to be adequate. It might be desirable to
> embed this class in a KPrinter class to make it possible to add KDE wide
> options not provided by Qt. In addition this class could give access to
> a printer's PPD file allowing applications to fine tune their print output.
> 
> 4) A kcontrol module should be written which allows printer configuration.
> sysAPI seems to provided al necassery functionality. Only the GUI part needs
> to be added.
> 
> Considerations
> ==============
> 
> *) The proposed printing architecture is not limited to Postscript output,
> although that is what the Qt printing classes produce.
> 
> *) The proposed sysAPS library can be used by non-KDE applications, including
> command line tools. Although the GNOME project is not interested in
> cooperation in this area, there are no compelling technical reasons which
> prevent them from adopting sysAPS, now or in the future.

-- 
     Richard Moore		rich@ipso-facto.freeserve.co.uk
http://www.robocast.com/	richard@robocast.com
http://developer.kde.org/	rich@kde.org

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