Details
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Bug
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Resolution: Done
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P2: Important
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None
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4.7.2, 5.0.0 Beta 1
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Mac operating system: Mac OS X 10.6.6
Qt 4.7.2 with Cocoa
Qt Master (685df07ff7e357f6848c50cffa311641afdca307)
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macOS
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26db7de13d5885067844532b5a5814181a0ddf16
Description
The QPrintDialog does not come up on the mac operating system like it does on the Linux and Windows operating system.
I have a simple test case attached to this report.
When the test printer button is pressed a basic dialog box pops up. Close the dialog box and then the print dialog box will flash on the screen but not stay up (on the mac operating system). If the exec for the QPrintDialog is called twice then the second call results in the QPrintDialog box being displayed. It looks like the QPrintDialog is receiving a signal it should not.
I have tried this test case on my Mac and a friends and it exhibits the same behavior.
On Mac OS X, when a QPrintDialog is used, a NSPrintPanel is used for a native print dialog. If you want a model print dialog (QPrintDialog::exec()), the method runModealWithPrintInfo is called:
int rval = [printPanel runModalWithPrintInfo:ep->printInfo];
NSPrintPanel does not run completely isolated though, and does report events to QApplication's event loops as you can see form this backtrace:
0 DebugApplication::notify main.cpp 22 0x100003ce7 1 QCoreApplication::notifyInternal qcoreapplication.cpp 822 0x1016a5e28 2 QCoreApplication::sendSpontaneousEvent qcoreapplication.h 234 0x10003b7e5 3 QApplication::setActiveWindow qapplication.cpp 2619 0x1000de28c 4 onApplicationWindowChangedActivation qapplication_mac.mm 3074 0x10003325f 5 -[QCocoaWindowDelegate windowDidResignKey:] qcocoawindowdelegate_mac.mm 321 0x10005a478 6 _nsnote_callback 0 0x7fff88a458ea 7 __CFXNotificationPost 0 0x7fff81bd3000 8 _CFXNotificationPostNotification 0 0x7fff81bbf578 9 -[NSNotificationCenter postNotificationName:object:userInfo:] 0 0x7fff88a3c84e 10 -[NSWindow resignKeyWindow] 0 0x7fff857ebb4f 11 -[NSWindow _changeKeyAndMainLimitedOK:] 0 0x7fff857324d4 12 -[NSWindow _makeKeyRegardlessOfVisibility] 0 0x7fff85732184 13 -[NSApplication _orderFrontModalWindow:relativeToWindow:] 0 0x7fff85976034 14 -[NSApplication _commonBeginModalSessionForWindow:relativeToWindow:modalDelegate:didEndSelector:contextInfo:] 0 0x7fff85975b6b 15 -[NSApplication beginModalSessionForWindow:] 0 0x7fff8597589c 16 -[NSApplication runModalForWindow:] 0 0x7fff859757be 17 -[NSPrintPanel runModalWithPrintInfo:] 0 0x7fff85ba748c 18 QPrintDialogPrivate::openCocoaPrintPanel qprintdialog_mac.mm 311 0x1000bee9e 19 QPrintDialog::exec qprintdialog_mac.mm 375 0x1000bf06b 20 PrintTest::mytest main.cpp 253 0x100003c62 21 PrintTest::qt_static_metacall moc_print.cpp 49 0x1000047ba 22 QMetaObject::activate qobject.cpp 3574 0x1016c4a21 23 QAbstractButton::pressed moc_qabstractbutton.cpp 207 0x1008e1fda 24 QAbstractButtonPrivate::emitPressed qabstractbutton.cpp 560 0x10054e1cc 25 QAbstractButton::mousePressEvent qabstractbutton.cpp 1096 0x10054e487 26 QWidget::event qwidget.cpp 8326 0x10014bdff 27 QAbstractButton::event qabstractbutton.cpp 1080 0x10054e6bd 28 QPushButton::event qpushbutton.cpp 683 0x10061ca84 29 QApplicationPrivate::notify_helper qapplication.cpp 4480 0x1000d3aed 30 QApplication::notify qapplication.cpp 4023 0x1000d4ecc 31 DebugApplication::notify main.cpp 30 0x100003f5d 32 QCoreApplication::notifyInternal qcoreapplication.cpp 822 0x1016a5e28 33 QCoreApplication::sendSpontaneousEvent qcoreapplication.h 234 0x10003b7e5 34 QApplicationPrivate::sendMouseEvent qapplication.cpp 3136 0x1000db48d 35 qt_mac_handleMouseEvent qt_cocoa_helpers_mac.mm 1267 0x100064d72 36 -[QCocoaView mouseDown:] qcocoaview_mac.mm 550 0x100053bb0 37 -[NSWindow sendEvent:] 0 0x7fff8583634f 38 -[QCocoaWindow sendEvent:] qcocoasharedwindowmethods_mac_p.h 183 0x10005822f 39 -[NSApplication sendEvent:] 0 0x7fff8576ba86 40 -[QNSApplication sendEvent:] qcocoaapplication_mac.mm 183 0x10005e67e 41 -[NSApplication run] 0 0x7fff857024da 42 QEventDispatcherMac::processEvents qeventdispatcher_mac.mm 615 0x10006bf82 43 QEventLoop::processEvents qeventloop.cpp 149 0x1016a258a 44 QEventLoop::exec qeventloop.cpp 204 0x1016a27dc 45 QCoreApplication::exec qcoreapplication.cpp 1094 0x1016a67de 46 QApplication::exec qapplication.cpp 3741 0x1000d7086 47 main main.cpp 273 0x100003b95
Since event processing can occur by calling NSPrintPanel runModalWithPrintInfo, what is currently in the event queue is relevant. In this examples case, after QDialog::exec() closes these are the events not processed yet:
notify :PrintTest WindowDeactivate-event (type-25) received notify :PrintTest ActivationChange-event (type-99) received notify :PrintTest FocusOut-event (type-9) received notify macintosh (aqua):QMacStyle FocusOut-event (type-9) received notify :PrintTest Paint-event (type-12) received notify print:QApplication ApplicationDeactivated-event (type-122) received
So what happens is that when NSPrintPanel causes these events to be processed, it causes the NSPrintPanel to get closed.
In this example, it is enough to call QApplication::processEvents() between basic.exec() and printDialog->exec() as it will clear the event queue before the NSPrintPanel is run, but this is just a work around to the large issue demonstrated here.