Reduce screen flickering on pressing non-existing keybindings

[anufrievroman]

Now, the screen is reloaded when whichever key is pressed, which causes a flick of the screen.
It should be that only functional keys reload the screen, while any other key presses are ignored.
In general, need to rewrite controls.py module.

[anufrievroman]

Flickering shouldn't happen on the no-keypress as well.

[mattbk]

I observe a flicker every 20 seconds when running Orange Pi Zero 2W (very low powered), more so when using an external monitor than when running over SSH. Is this related to to curses.halfdelay()? Not sure if this is the same thing you are seeing or not.

[anufrievroman]

Most likely, yes, on low power machines it's quite noticable. It's related to this even that it refreshes the screen anyways even if nothing was pressed during this half delay

[mattbk]

I think changing this line to stdscr.refresh() removes the flicker on my device but doesn't impact anything else--but I haven't tested everything, nor do I know anything beyond what I've read in the past few days.

calcure/calcure/__main__.py

Line 1034 in 6b10656

stdscr.clear()

[anufrievroman]

The difference, is that refresh() does not clear the internal structure of the stdscr but only draws what was changed or something like that. I tried, and you're right, it solves the flickering (I guess clear takes time, hence flickering) but I could notice some artifacts, like letters left behind when I switch between split and non split screen with / (if event name is short). But maybe those artifacts could be removed by redrawing background every time or something like that...

[anufrievroman]

For example, we can fix that artifact by placing self.stdscr.clear() on line 810 of main, but I am not sure if that reintroduces the flickering, as my computer doesn't have noticeable flickering anyway

[mattbk]

Thanks, but the clear() is still very obvious on this machine. I will look into it more while I keep an eye out for artifacts.