Avoid deadlock during window hiding.

Because we do event processing in polishAndSync, hide() or
handleObscurity() might have been called by the time we
continue execution. We already handled that windowDestroyed()
was called.

Change-Id: If45bcf3fa18cef1a60ca31bc26d3830045f581d9
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Use categorized logging for all things scenegraph.

Change-Id: I865ee838b0fd6c257b7189f24130012b98206fd1
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Docs: clarify the relation between default alpha and format.

Reformat the new API docs the get rid of the unnecessary stars.

And fix some typos.

Change-Id: I09dcb3bea55cfd7b9209a4e0ad43e28a47fd1fa4
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Avoid direct GL calls in Qt Quick examples and tests

Change-Id: I204a5513708aeff5cae00d06d4f0c27c20a13ace
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Add grabFramebuffer() to QQuickWidget and use it in the autotest

This introduces the need for a grab function in QQuickWidget.
The render control has one already so there is no reason for not exposing
this in QQuickWidget too.

This also means that a relatively meaningful autotest can be now be added.

[ChangeLog][QtQuick] Added QQuickWidget::grabFramebuffer() for capturing the content into a QImage.

Task-number: QTBUG-37589
Change-Id: I5ca8192c0ef8dab4f076a4db27b64aebe3359bb8
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>