[Qt-interest] [Qt-embedded-interest] pixel errors in QListWidget when setting Qt::WA_NoSystemBackground

[Atlant Schmidt]

Markus:

  To me, it looks like the anti-aliasing is going wrong when there
  isn't a "SystemBackground" for those objects to be drawn against.

  But that's just a guess and doesn't really help you get closer
  to a solution, so let me ask a question:

  When you say ". In order to get correct "rounded corners" for the
  dialog I am drawing the whole dialog by myself.", what do you
  mean by that? The usual way to get the effect you want is
  provide a background-image or border-image that contains
  the "rounded corners" with appropriate 9-slicing hints to allow
  Qt to stretch the image without distorting the corners.

  That method works, even in Qt 4.6.x QWS.

                                      Atlant

________________________________
From: qt-embedded-interest-bounces+aschmidt=dekaresearch.com at qt.nokia.com [mailto:qt-embedded-interest-bounces+aschmidt=dekaresearch.com at qt.nokia.com] On Behalf Of Markus Franke
Sent: Friday, June 10, 2011 09:58
To: qt-interest at qt.nokia.com; qt-embedded-interest at qt.nokia.com
Subject: [Qt-embedded-interest] pixel errors in QListWidget when setting Qt::WA_NoSystemBackground


Dear all,

I am observing strange pixel errors within the icons of items of a QListWidget. (see attached screenshot)

Basically I am creating a QDialog derived class which holds the QListWidget. In order to get correct "rounded corners" for the dialog I am drawing the whole dialog by myself. The pixel errors in the screenshot attached appeared when I enabled the Qt::WA_NoSystemBackground flag for the QDialog. If I remove this flag the images get displayed correctly again but unfortunately the "rounded corners" will then be wrong. Below the QListWidget I added a QLabel with the same icon as in the QListWidget and there the problem does not occur.

Furthermore, the problem only can be observed for the QWS version of Qt Everywhere 4.6.3. The X11 version does not show this behaviour.

Thanks for any comments on this,

Markus Franke

PS.: I sent this message to both lists because I think it's somewhat related to both versions of Qt.




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