On Tue, Mar 3, 2020, 8:35 PM <vaillant.rodol...@gmail.com> wrote: > Some additional reflection on the topic: > > Personally I don't notice any delay when filtering events from Maya's main > window (Maya 2019). > IMHO I'm not sure this is as big of an issue as you may think it is. I > need to test this more over time though. > Because my intution tells me events are usually very light and their load > stay the same regardless of the scene complexity, > I'm really not sure why you would get noticable lag (even accounting for > python overhead) >
Well Qt does document a warning about possible performance implications of filtering every event in the application even from the C++ side of things: https://doc.qt.io/archives/qt-4.8/eventsandfilters.html "It is also possible to filter all events for the entire application, by installing an event filter on the QApplication or QCoreApplication object. Such global event filters are called before the object-specific filters. This is very powerful, but it also slows down event delivery of every single event in the entire application; the other techniques discussed should generally be used instead." So it would be reasonable to assume it would be far slower to put a python function into the path of the main event loop that is catching every event in the app. That would be every paint event. Maybe could impact a large amount of redrawing in the app? > I haven't tried it yet but brave people might want to do event filtering > inside their C++ plugin: > > https://around-the-corner.typepad.com/adn/2012/09/access-the-qt-event-loop-in-maya.html > Since we can access Maya Qt core application from there as well. > > #include <QtCore/QCoreApplication> > QCoreApplication *app = qApp; > void QObject::installEventFilter (QObject *filterObj) > > > Cheers > > > 2018年5月28日月曜日 21時57分54秒 UTC+9 Marcus Ottosson: >> >> Yes, this is possible. >> >> from PySide import QtGui, QtCore >> class MyEventHandler(QtCore.QObject): >> def eventFilter(self, target, event): >> if event.type() == event.KeyPress: >> print("That's a keypress") >> return super(MyEventHandler, self).eventFilter(target, event) >> >> handler = MyEventHandler() >> >> app = QtGui.QApplication.instance() >> app.installEventFilter(handler)# app.removeEventFilter(handler) >> >> That would normally be fine, *however* if there is one object where you >> never want a (Python) event filter, it would be the QApplication or Maya’s >> MainWindow. Because what happens is that *every single event* in Maya >> which was previously highly optimised C++ now has to pass through your >> Python function. Which means that even if your function does nothing but >> pass the event through, it still has a *significant* effect on >> performance. For starters, you should notice that with this filter >> installed, navigating in the viewport suddenly has a slight delay. As if >> the click caused a minor lag before eventually allowing you to dolly the >> camera. >> >> To put a picture in your head, here’s why. >> >> Information Super Highway >> >> --------------\ /---------------> >> -------------- \ /----------------> >> ---------------->-------------/-----------------> >> -------------- / \-----------------> >> --------------/ \----------------> >> C++ Python C++ >> >> Instead, what you should consider, if you are able, is installing an >> event filter *not* in QApplication or Maya’s main window, but in *your >> widget*. >> >> class MyWidget(QtGui.QDialog): >> def __init__(self, parent=None): >> super(MyWidget, self).__init__(parent) >> >> handler = MyEventHandler() >> mywidget = MyWidget() >> mywidget.installEventFilter(handler) >> >> But *most* preferably, would be to not use an event filter, and instead >> override the event handler called only on keypress events >> <http://doc.qt.io/qt-5/qwidget.html#keyPressEvent>. >> >> class MyWidget(QtGui.QDialog): >> def __init__(self, parent=None): >> super(MyWidget, self).__init__(parent) >> >> def keyPressEvent(self, event): >> print("That's a press!") >> return super(MyWidget, self).keyPressEvent(event) >> >> That way, there is zero overhead on any event handling, other than the >> one you override. >> >> Hope it helps! >> >> >> On 26 May 2018 at 07:27, Alexey Vasilyev <ole...@gmail.com> wrote: >> >>> Hi. >>> I'm new to Maya programming. >>> I'm curious if it's possible to track keypress events in Maya main >>> window using PySide or any other way? >>> For example, when cube primitive is selected, I want to be able to >>> increase or decrease its subdivisions using Left and Right arrows. When >>> it's not selected, I want arrow keys to function in the default way. >>> Thanks. >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Python Programming for Autodesk Maya" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to python_inside_maya+unsubscr...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/python_inside_maya/c7024d27-4a67-448e-9e57-a873ff85dcbc%40googlegroups.com >>> <https://groups.google.com/d/msgid/python_inside_maya/c7024d27-4a67-448e-9e57-a873ff85dcbc%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- > You received this message because you are subscribed to the Google Groups > "Python Programming for Autodesk Maya" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to python_inside_maya+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/python_inside_maya/31a77359-f8e0-466d-8c68-ea826575cecb%40googlegroups.com > <https://groups.google.com/d/msgid/python_inside_maya/31a77359-f8e0-466d-8c68-ea826575cecb%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Python Programming for Autodesk Maya" group. 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