Modify Main Window callbacks

[jshahbazi]

I would like to be able to modify the callbacks for the main window, such as the render callback and the close callback. I need to be able to set a threading/multiprocessing event when the user closes the window so I can terminate any threads/processes running in the background. I'd also like to be able to modify the render just to have more control (such as slowing down the refresh rate to conserve CPU power and/or reduce energy drain).

I can do this for child windows, but with the existing system I will always at least two windows open: an empty main window and a sub window. This clutters up the UX.

[hoffstadt]

We will add the close callback for the main window however you should have access to the main window's render callback. You just leave the handler keyword out:

set_render_callback("some_function")

As far as the refresh rate goes, you can currently adjust that (hackily) by using python's sleep function. In one of the upcoming releases we will add settings for adjusting framerate, including disabling vsync.

Is there a certain framerate you are trying to hit?

[jshahbazi]

Great! Thank you. Just adding a sleep is fine by me. For what I'm doing, I'm sharing a lot of data between threads/processes that will be displayed in the GUI, and there's some extra processing that happens for that for each render. So too high of a refresh rate and it'll be using the CPU heavily. But 30 (even 20) fps is more than fine for what I'm doing.

I did test out using a sleep on a child window render callback and it worked well.

[hoffstadt]

Glad to hear. DearPyGui works best at 30fps and greater but I believe 20fbs should be fine also.

Out of curiosity, have you tried DearPyGui's run_async_function? It allows for asynchronous function calls that tie in easily with the whole render loop situation.

[hoffstadt]

Also did the main render loop work?

You can also use the event loop of the whole program by replacing start_dearpygui() with:

setup_dearpygui()
while True:
    # do other stuff
    render_dearpygui_frame()
cleanup_dearpygui()

[jshahbazi]

The main render callback did work, so thank you!

This following works, but when I do it this way, I can't close the window by clicking on the x at the top:

setup_dearpygui()
while True:
    # do other stuff
    render_dearpygui_frame()
cleanup_dearpygui()

I looked at the run_async_function() a little bit, but I haven't given it a try yet. It could be useful for certain things, though. I just haven't gotten that far yet.

[hoffstadt]

Awesome.

And sorry that example will not allow you to close. ha. Instead of while True: you would need something else in place of true. i.e.:

add_checkbox("Run", default_value=True)

setup_dearpygui()
while get_value("Run"):
    # do other stuff

    render_dearpygui_frame()
cleanup_dearpygui()

But the actual thing that is needed is a main window on close callback... which we don't have yet. Or a is_dearpygui_running command. I will add that for the next release. Hopefully releasing tonight.