launch_promise_thread()#

Create a Py5Promise object that will store the returned result of a function when that function completes.

Examples#

def setup():
    global promise
    py5.size(200, 100)
    promise = py5.launch_promise_thread(load_data)


def load_data():
    return py5.load_json('http://py5coding.org/files/secret_message.json')


def draw():
    py5.background(0)
    if promise.is_ready:
        py5.text(promise.result['msg'][:(py5.frame_count // 25)], 20, 50)

Description#

Create a Py5Promise object that will store the returned result of a function when that function completes. This can be useful for executing non-py5 code that would otherwise slow down the animation thread and reduce the Sketch’s frame rate.

The Py5Promise object has an is_ready property that will be True when the result property contains the value function f returned. Before then, the result property will be None.

The name parameter is optional but useful if you want to monitor the thread with other methods such as has_thread(). If the provided name is identical to an already running thread, the running thread will first be stopped with a call to stop_thread() with the wait parameter equal to True.

Use the args and kwargs parameters to pass positional and keyword arguments to the function.

Use the daemon parameter to make the launched thread a daemon that will run without blocking Python from exiting. This parameter defaults to True, meaning that function execution can be interupted if the Python process exits. Note that if the Python process continues running after the Sketch exits, which is typically the case when using a Jupyter Notebook, this parameter won’t have any effect unless if you try to restart the Notebook kernel. Generally speaking, setting this parameter to False causes problems but it is available for those who really need it. See stop_all_threads() for a better approach to exit threads.

The new thread is a Python thread, so all the usual caveats about the Global Interpreter Lock (GIL) apply here.

Signatures#

launch_promise_thread(
    f: Callable,  # function to call in the launched thread
    name: str = None,  # name of thread to be created
    *,
    daemon: bool = True,  # if the thread should be a daemon thread
    args: tuple = None,  # positional arguments to pass to the given function
    kwargs: dict = None  # keyword arguments to pass to the given function
) -> Py5Promise

Updated on September 04, 2022 12:55:11pm UTC