[Development] Rotating JPEG images by default

[Alberto Mardegan]

On 04/22/2015 09:54 PM, André Pönitz wrote:
> However, we do have context here, namely existing behaviour in Qt 5.x,
> as well as certain general promises given for changes between Qt 5.x and
> Qt 5.(x+1).

I see it as a long standing bug which finally got fixed.

But the problem is that the behavioural change is already out there, 
with Qt 5.4. I think it would be easier to have a runtime check on the 
QT version (and eventually drop the local workarounds) than to introduce 
another behavioural change in the next Qt version.

> Even though "no behaviour change" isn't one of the guarantees, I don't
> think rotating part of an application's GUI by 90 degrees behind the
> developer's back is acceptable.

It's very unlikely that such images are used as part of the GUI. But I'm 
nitpicking, I certainly agree with you that the behavioural change is a 
major annoyance.
However, if application developers had filed this bug earlier, instead 
of silently working around it in their application, we wouldn't even be 
discussing this. So, in a way, I believe that if this behavioural change 
affects someone in a bad way, some part of the blame falls on his side too.

> If an application accepts such change it should announce it by explicitly
> opting in, i.e. by setting a flag/calling a function/whatever.

Actually, this sounds like a very good idea; I wouldn't mind if this was 
a opt-in, as long as the behaviour was configurable with a single line 
change (a static method on QGuiApplication, maybe?).
As long as I don't have to change it in every single QImage/QML Image, 
all is fine to me.

Ciao,
   Alberto