Threading

Formify implements a few helper functions to move expensive calculations outside the Ui thread:

formify.tools.BackgroundMethod

Bases: Thread

A wrapper to execute a function in a background thread.

Usage:

import time

@formify.tools.BackgroundMethod
def expensive_calculation(text):
        time.sleep(1)
        print(text)

expensive_calculation("1")
expensive_calculation("2")
expensive_calculation("3")
print("Hello") # will be printed first

Output:

Hello
1
2
3

__init__(target, lazy=None, cleanup=None)

Parameters:

Name	Type	Description	Default
target	typing.Callable	Target method (is executed, when the BackgroundMethod instance is called)	required
lazy	bool	A call is skipped, if a newer one is queued.	None
cleanup	typing.Callable	Runs after the target, if provided.	None

Returns:

Name	Type	Description
BakgroundMethod	typing.Callable	A callable thread, that executes the target with Callable. If a cleanup is provided, this runs afterwards.

__call__(*args, **kwargs)

Executes the self.target with the provided args and *kwargs.

formify.tools.LazyBackgroundMethod

Bases: BackgroundMethod

Executes only the latest call. Helpful for updating a plot and wherever else you are only interested in the latest result.

Usage:

import time

@formify.tools.LazyBackgroundMethod
def expensive_calculation(text):
        time.sleep(1)
        print(text)

expensive_calculation("1")
expensive_calculation("2") # will not be executed!
expensive_calculation("3")
print("Hello")

Output:

Hello
1
3

formify.tools.do_in_ui_thread(func)

Immediately executes func in the main thread (UI thread). Useful when interacting with UI elements.

Usage:

textarea = formify.ControlTextarea("Output")

@formify.tools.BackgroundMethod
def expensive_calculation(text):
        time.sleep(1)

        def output_text():
                textarea.value += text + "\n"

        do_in_ui_thread(output_text)

expensive_calculation(1)
expensive_calculation(2)
expensive_calculation(3)

The textarea should contain:

1
2
3

Parameters:

Name	Type	Description	Default
func	typing.Callable	fucntion to be called (without any arguments)	required