QGraphicsEffect on Mac OS X does not work with QWidgets

njeisecke

Hi!

I've been playing around with setting a QGraphicsBlurEffect on a simple widget.

This works on Linux and Windows but does not work on Mac OS X.

I got it working (somehow) by using -graphicssystem raster, but this is not a really an option for Mac OS X because of various painting artefacts (shouldn't raster become default on Mac OS X with Qt 4.7?)

The docs do not mention anything about limitations on Mac OS X and event google doesn't know.

I've prepared a small example. Simply a blurred button:

@
#include <QtGui>

int main(int argc, char **argv)
{
QApplication app(argc, argv);

QPushButton *b = new QPushButton("I should be a blurry button on any platform");
QGraphicsBlurEffect *e = new QGraphicsBlurEffect(b);
b->setGraphicsEffect(e);

b->show();

return app.exec();
}
@

Does anybody have any idea?

Thanks,

Nils

frankcyblogic.de

Oh, that is new to me, that it works with widgets (especially with top-level once). By the way the raster engine is said to become the default with 4.8, although there are still many bugs:http://bugreports.qt.nokia.com/browse/QTBUG-12615 .

mcohoon

Have you had any success resolving this? I've been using 4.6.* and have not been able to get QGraphicsEffect to work properly, does 4.7 do any better?

njeisecke

With 4.8 the effect works on Mac OS X (thank to Alien Widgets, I guess):

@
#include <QtGui>

int main(int argc, char **argv)
{
QApplication app(argc, argv);

QWidget *w = new QWidget;
QHBoxLayout *l = new QHBoxLayout(w);

QPushButton *b = new QPushButton("I should be a blurry button on any platform");
QGraphicsBlurEffect *e = new QGraphicsBlurEffect(b);
b->setGraphicsEffect(e);

l->addWidget(b);

w->show();

return app.exec();
}
@

jimmytfp

Hi,
This crashes on my 4.8.1 installation.
Jimmy

System Version: OS X 10.8 (12A269)
Kernel Version: Darwin 12.0.0
Boot Volume: maine
Boot Mode: Normal
Computer Name: air-jimmy
User Name: jimmy (jimmy)
Secure Virtual Memory: Enabled
Time since boot: 20:43

Bargonaut

I also can not use any QGraphicsEffects on OS X without it crashing.
It runs just fine if I don't set the QGraphicsEffect on the QPushButton,
but if I do, it crashes as soon as it tries to draw/paint.
Qt 4.8.3

This is the error displayed at runtime:
QPainter::begin: Widget painting can only begin as a result of a paintEvent
QPainter::translate: Painter not active
The program has unexpectedly finished.

///////////////////////////////////////////////////////////////////////////////////
Process: QGE_Test [68591]
Path: /Users/USER/*/QGE_Test.app/Contents/MacOS/QGE_Test
Identifier: com.yourcompany.QGE_Test
Version: ??? (???)
Code Type: X86-64 (Native)
Parent Process: Qt Creator [67145]

Date/Time: 2012-11-12 12:46:01.941 -0800
OS Version: Mac OS X 10.7.4 (11E53)
Report Version: 9

Interval Since Last Report: 256420 sec
Crashes Since Last Report: 13
Per-App Interval Since Last Report: 4 sec
Per-App Crashes Since Last Report: 1
Anonymous UUID: 0B870E43-6B86-4D58-BEE4-896207A07B53

Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000

VM Regions Near 0:
-->
__TEXT 0000000100000000-0000000100003000 [ 12K] r-x/rwx SM=COW /Users/USER/*/QGE_Test.app/Contents/MacOS/QGE_Test

Application Specific Information:
objc[68591]: garbage collection is OFF

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 QtGui 0x0000000100706d78 QGraphicsBlurEffect::draw(QPainter*) + 72
1 QtGui 0x00000001000e43cf QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) + 2607
2 QtGui 0x00000001000e4b34 QWidgetPrivate::paintSiblingsRecursive(QPaintDevice*, QList<QObject*> const&, int, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) + 1460
3 QtGui 0x00000001000e3e50 QWidgetPrivate::drawWidget(QPaintDevice*, QRegion const&, QPoint const&, int, QPainter*, QWidgetBackingStore*) + 1200
4 QtGui 0x00000001000337da -[QCocoaView drawRect:] + 1786
5 com.apple.AppKit 0x00007fff8d9eb97a -[NSView _drawRect:clip:] + 3758
6 com.apple.AppKit 0x00007fff8da18b4f -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] + 1583
7 com.apple.AppKit 0x00007fff8da18f7b -[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:] + 2651
8 com.apple.AppKit 0x00007fff8d9e8f55 -[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 1032
9 com.apple.AppKit 0x00007fff8d9e844f -[NSThemeFrame _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:] + 270
10 com.apple.AppKit 0x00007fff8d9e386f -[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:] + 4755
11 com.apple.AppKit 0x00007fff8d9dc2ed -[NSView displayIfNeeded] + 1676
12 com.apple.AppKit 0x00007fff8da999ab -[NSWindow _reallyDoOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 1306
13 com.apple.AppKit 0x00007fff8da993a8 -[NSWindow _doOrderWindow:relativeTo:findKey:forCounter:force:isModal:] + 807
14 com.apple.AppKit 0x00007fff8da9902c -[NSWindow orderWindow:relativeTo:] + 154
15 com.apple.AppKit 0x00007fff8da988cd -[NSWindow makeKeyAndOrderFront:] + 49
16 QtGui 0x000000010002a253 QWidgetPrivate::show_sys() + 1123
17 QtGui 0x00000001000eabd8 QWidgetPrivate::show_helper() + 408
18 QtGui 0x00000001000eaf0f QWidget::setVisible(bool) + 511
19 com.yourcompany.QGE_Test 0x0000000100002ab7 QWidget::show() + 39 (qwidget.h:494)
20 com.yourcompany.QGE_Test 0x00000001000028da main + 970 (main.cpp:20)
21 com.yourcompany.QGE_Test 0x00000001000024e4 start + 52