[Interest] What is the difference.

[Karl Ruetz]

On Sep 22, 2014, at 10:25 AM, william.crocker at analog.com wrote:

> On 09/22/2014 11:10 AM, Thiago Macieira wrote:
>> On Monday 22 September 2014 11:01:23 william.crocker at analog.com wrote:
>>> Gang:
>>> 
>>> While we are talking about the need for a Q[Core]Application...
>>> 
>>> What is the difference between;
>>> 
>>>      QCoreApplication(argv,argc);
>>> 
>>> and
>>> 
>>>      QApplication(argc,argc,false);  // Note GUIEnabled=false
>> 
>> It creates a QApplication, which enables a bunch of backend things, without
>> also connecting to the display server.
> 
> When my normally-GUI application is run "off-line"
> (to create plot images in files as opposed to drawing
> them on the screen) I found that I had to use the
> second option.
> 
> I do not remember the specifics... might have had something
> to do with fontconfig or the use of the QImage class.
> 
>> 
>> Note that this constructor is removed in Qt 5.
>> 
> 
> Is that another reason why I can never use Qt 5?

I have a similar problem with a “console” program that creates PDF reports that include graphics.
I have to use the QApplication, with connections to the Display and all that implies when all I really want to do is use QPainter and QPdfwriter to create a report.
It is rather inconvenient, but workable.

Karl