schrodinger.utils.qapplication module

Functions for managing the global QApplication instance.

Typical usage:

if __name__ == ‘__main__’:

af2.start_application(MyPanel.panel)

(Note that the start_application function is available from the af2 namespace)

schrodinger.utils.qapplication.ApplicationMode

alias of schrodinger.utils.qapplication.RunMode

exception schrodinger.utils.qapplication.CantCreateQApplicationError(msg='', *args, **kwargs)

Bases: RuntimeError

__init__(msg='', *args, **kwargs)

args

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

schrodinger.utils.qapplication.require_application(func=None, create=False, use_qtcore_app=False)

Use this decorator on functions that require a QApplication to run. When the decorated function is called, this will check whether a QApplication exists. If it does not, a RuntimeError will be raised unless create=True, which will cause a QApplication to be created.

Parameters

• func – the function to decorate

• create (bool) – whether to create a QApplication if one does not exist

• use_qtcore_app (bool) – Whether to create the application using the QtCore module instead of the QtWidgets module.

schrodinger.utils.qapplication.get_application(create=True, use_qtcore_app=False)

Gets the global QApplication instance. By default, creates one if none exists.

Parameters

• create (bool) – Whether to create a new application if none exists.

• use_qtcore_app – Whether to create the application using the QtCore module instead of the QtWidgets module. Has no effect if create is False.

Raises

CantCreateQApplicationError – if use_qtcore_app is False and importing QtWidgets fails (e.g. due to missing graphics libraries)

Returns

the application

Return type

QApplication or None

schrodinger.utils.qapplication.is_core_application()

Return whether the application instance is a QtCore application (as opposed to a QtWidgets application).

Returns

Whether there is a QtCore application or None if there’s no application

Return type

bool or NoneType

schrodinger.utils.qapplication.get_app_mode()

Returns the current application mode, which is a member of the ApplicationMode enum.

schrodinger.utils.qapplication.in_canvas()

Checks whether we are currently running from within canvas

schrodinger.utils.qapplication.start_application(main_callable, use_qtcore_app=False)

Begins the application’s event loop using the exec_ method. The main callable is called via timer from within the event loop. This function is meant to be used when running in standalone scripts as follows:

if __name__ == ‘__main__’:

application.start_application(main)

Using this function to launch standalone scripts/panels more closely mimics the way Python is run under Maestro. For example, a panel may be presented with MyPanel.show() without having to call application.exec_().

This is generally intended for use with GUI scripts.

Parameters

• main_callable (callable) – the function/method to be run in the event loop, commonly a module level main function or MyPanelClass.panel

• use_qtcore_app (bool) – Whether to create the application using the QtCore module instead of the QtWidgets module. Set to True for scripts that are non-GUI and/or need to run on machines that have no display.

schrodinger.utils.qapplication.run_application(main_callable, use_qtcore_app=True)

This function is the same as start_application with two important differences:

1. Creates a QCoreApplication by default

2. Quits the application as soon as the main_callable function returns

   and does a system exit with that return value

This is generally intended for use by non-GUI, commandline scripts.

schrodinger.utils.qapplication.process_events(flags=None)

Calls processEvents on the main event loop. Requires a QApplication.

Parameters

flags – passed to processEvents. See QApplication.processEvents for documentation

Raises

RuntimeError – if there is no QApplication

schrodinger.utils.qapplication.quit_application()

Quits the application.