napari.qt.threading.WorkerBase¶

class napari.qt.threading.WorkerBase(*args, SignalsClass=<class 'napari._qt.qthreading.WorkerBaseSignals'>, **kwargs)[source]¶

Bases: PyQt5.QtCore.QRunnable

Base class for creating a Worker that can run in another thread.

Parameters: SignalsClass (type, optional) – A QObject subclass that contains signals, by default WorkerBaseSignals

signals¶

signal emitter object. To allow identify which worker thread emitted signal.

Type: WorkerBaseSignals

Methods

Attributes

property abort_requested¶

Whether the worker has been requested to stop.

Return type: bool

autoDelete(self) → bool ¶

create(Callable[[], None]) → QRunnable¶

property is_running¶

Whether the worker has been started

Return type: bool

quit()[source]¶

Send a request to abort the worker.

Note

It is entirely up to subclasses to honor this method by checking self.abort_requested periodically in their worker.work method, and exiting if True.

Return type: None

run()[source]¶

Start the worker.

The end-user should never need to call this function. But it cannot be made private or renamed, since it is called by Qt.

The order of method calls when starting a worker is:

calls QThreadPool.globalInstance().start(worker)
|               triggered by the QThreadPool.start() method
|               |             called by worker.run
|               |             |
V               V             V
worker.start -> worker.run -> worker.work

This is the function that actually gets called when calling QThreadPool.start(worker)(). It simply wraps the work() method, and emits a few signals. Subclasses should NOT override this method (except with good reason), and instead should implement work().

setAutoDelete(self, bool)¶

start()[source]¶

Start this worker in a thread and add it to the global threadpool.

The order of method calls when starting a worker is:

calls QThreadPool.globalInstance().start(worker)
|               triggered by the QThreadPool.start() method
|               |             called by worker.run
|               |             |
V               V             V
worker.start -> worker.run -> worker.work

work()[source]¶

Main method to execute the worker.

The end-user should never need to call this function. But subclasses must implement this method (See GeneratorFunction.work() for an example implementation). Minimally, it should check self.abort_requested periodically and exit if True.

Examples

class MyWorker(WorkerBase):

    def work(self):
        i = 0
        while True:
            if self.abort_requested:
                self.aborted.emit()
                break
            i += 1
            if i > max_iters:
                break
            time.sleep(0.5)

Return type: Union[Exception, Any]