[Development] Qt 5.13 & 5.14 add device-independent pixels to device-dependent

[Christoph Cullmann]

Hi,

On 2020-02-13 19:29, Thiago Macieira wrote:
> On Thursday, 13 February 2020 09:53:11 PST Thiago Macieira wrote:
>> I can confirm krdc is affected just the same way that KMail and 
>> VirtualBox
>> are: it works on screen 1, but fails to repaint on screen 2.
>> 
>> It's a much simpler application than KMail to debug. I can reproduce 
>> this by
>> using it to VNC into my Mac machine or to RDP into my Windows one. The
>> trick must be here somewhere:
>> 
>> https://github.com/KDE/krdc/tree/master
> 
> More debugging:
> 
> When on screen 2, the central widget in VNC mode does update if I 
> shrink the
> window, but not if I enlarge it. The menu bar drop downs do draw 
> properly and
> in the right position, but the toolbar extension does not. My guess is 
> that
> the menu bar drop down is a separate X window while the toolbar is not. 
> See
> https://bugreports.qt.io/secure/attachment/92037/
> Screenshot_20200213_100723.png.
> 
> I've captured a *.debug=true log of krdc in both screens, where all I 
> did was
> connect (from the command-line) and draw one of the corners a little to
> expand, then quit. See
> https://bugreports.qt.io/secure/attachment/92039/krdc-screen1.log
> https://bugreports.qt.io/secure/attachment/92038/krdc-screen2.log
> 
> I still can't find an example in qtbase that has the same issue.

Perhaps this helps you:

I had in Kate/Konsole and Co. broken repainting as soon as winId() was 
called
on any non-native widget, see:

https://bugs.kde.org/show_bug.cgi?id=411965

If this is unrelated, just ignore me ;=)

Greetings
Christoph

-- 
Ignorance is bliss...
https://cullmann.io | https://kate-editor.org