diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/widgets/kernel/qwidget.cpp | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp index 14012219f9..a5ad101201 100644 --- a/src/widgets/kernel/qwidget.cpp +++ b/src/widgets/kernel/qwidget.cpp @@ -2191,8 +2191,26 @@ void QWidgetPrivate::updateIsTranslucent() const int oldAlpha = format.alphaBufferSize(); const int newAlpha = q->testAttribute(Qt::WA_TranslucentBackground)? 8 : 0; if (oldAlpha != newAlpha) { - format.setAlphaBufferSize(newAlpha); - window->setFormat(format); + // QTBUG-85714: Do this only when the QWindow has not yet been create()'ed yet. + // + // If that is not the case, then the setFormat() is not just futile + // but downright dangerous. Futile because the format matters only + // when creating the native window, no point in changing it + // afterwards. Dangerous because a QOpenGLContext or something else + // may eventually query the QWindow's format(), in order to ensure + // compatibility (in terms of native concepts such as pixel format, + // EGLConfig, etc.), and if we change it here, then the returned + // format does not describe reality anymore. (reality being the + // settings with which the native resource was created). + // + // Whereas if one does a destroy()-create() then this all here + // won't matter because the format is updated in + // QWidgetPrivate::create() again. + // + if (!window->handle()) { + format.setAlphaBufferSize(newAlpha); + window->setFormat(format); + } } } } |