[Interest] QDatastream, QMap, QImage serialization

[Thiago Macieira]

On Monday, 21 May 2018 11:46:54 -03 Christoph Feck wrote:
> Maybe for Qt6 we could have a thin QtGuiCore library, which manipulates
> image data and colors, but does not have a dependency on GUI servers
> (OpenGL, X11, etc.)

I think even that name was proposed before. I don't remember if it was during 
the Qt 5.0 development time or not.

But we decided not to. With most of the actual windowing code moved to plugins 
(and libraries loaded by those plugins, like libQt5XcbQpa), QtGui *is* that 
GuiCore library.

It's just that the distinction of which classes can be safely used outside the 
GUI thread or even without QGuiApplication isn't very clear. Said library 
would make it very clear and almost impossible to violate, but it could also 
preclude certain possible optimisations.

For example, QImage::paintEngine() queries the platform plugin to see if it 
can provide a better image painter than QRasterPaintEngine (for HW 
acceleration, I suppose). That is only possible because QImage is in QtGui. 
Currently, there are no platforms taking this opportunity, but do we want to 
prevent it from ever happening?

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center