displayio - pause display refresh (for setting up a bunch of items)

[ladyada]

the opposite of refresh_soon() :)

[deshipu]

maybe a context manager would work for this, pausing the display for the duration of executing the code inside of it

[deshipu]

something like:

with display.frame: # pauses the refresh here
   ...
# unpauses and schedules a new refresh here

[tannewt]

I expect to experiment a bunch with frame synchronization in 4.x once we can actually update a frame faster than the display does. Thanks for making an issue for it.

[tannewt]

Ok, so I think I know what I want to replace wait_for_frame and refresh_soon with. I think we want an explicit refresh call that blocks until new pixels have been sent to the display (but not wait on epaper refresh.)

For fast screens it'll have a target_fps kwarg that takes a target frame rate and skips the pixel update if the time since the last frame is more than the gap needed for the frame rate. It'll also have an max_delay that will cause an exception if the time since the last updated frame is greater than the given delay.

[ladyada]

do you want to have anything for pausing so that if you have text on top of a bitmap you dont have a few characters appear at a time

[tannewt]

@ladyada You don't need to pause because a refresh will only happen when you call refresh. It won't auto happen at all. (though the terminal/supervisor will call it too)

[ladyada]

ohh, wait, so you will have to poke the display for each drawing? how will that work if you draw/change a bitmap like with turtle?

[tannewt]

You'll want to call refresh from time to time and the dirty area will be updated. I don't think it's too common to have code that may run much faster than the display can update.

[ladyada]

totally cool - i just wanted to know what to expect - the arduino code's like this too so i'm pretty used to it!