[Development] Adding CPD support to Qt print dialog

[Till Kamppeter]

On 19/09/2022 15:43, Tor Arne Vestbø wrote:
>>
>> First is to create a new Qt print backend, what, instead of communicating directly with CUPS, communicates with the CPDB backends. It is some kind of "middle end", on one end being a Qt print backend and on the other end being a CPDB frontend.''
> 
> This sounds like a good first step. It doesn’t involve any of the GUI bits, just the enumeration and communication with the various CPDB-exposed printers.
> 
> Since the QtPrintSupport module doesn’t depend on DBUS today (AFAIK), the CPDB print backend should be a plugin.
>

OK, Gaurav so you should be able to provide the CPDB support as a plugin 
(Tor, is this a Qt print backend like the one for CUPS for example?).

>> The second is to throw the backend concept of the Qt dialog over board and replace it by CPDB, the Qt print dialog itself using cpdb-libs to connect to backends, which are now only the CPDB backends, no Qt print backends any more. By conditional compiling one could decide here at build time to use the CPDB concept, the old Qt print backend concept, or both (and in that case which has priority).
> 
> This can only be done if CPDB is available on all platforms Qt supports.

OK, so replacing Qt's backend concept by CPDB would only work under 
Linux, requiring conditionals to stay with the Qt concept for other 
platforms. So we stay with the approach of implementing the CPDB support 
in a Qt print backend/plugin.

    Till