Re: Cygwin terminal weirdness

[Warren Young <wyml at etr-usa dot com>]

On Sep 13, 2015, at 12:36 PM, Andrey Repin <anrdaemon@yandex.ru> wrote:
> 
> Call "man" on a sufficiently long topic. man bash would be quite sufficient.
> Or just `less` a long enough text.
> Hold down "End" key.
> The screen buffer will jump and tear repeatedly, until you release the key.

That sounds like a video card performance issue, not a Cygwin, mintty, or less issue.

I just tried it here on a VM hosted on a box with an NVIDIA GeForce GTX 680MX GPU, and all I saw was normal redrawing, with scarcely any tearing.  That chip is about 3 years old, which probably still outperforms any current CPU-integrated GPU.

There are some small mitigations that might help.

One would be to convince the maintainers of less to be smarter about repainting the whole screen when it isnât necessary.  But given that they havenât fixed the horizontal scrolling bug in the ~20 years Iâve been using it, I wouldnât hold out hope on that front.

Another would be to make mintty double-buffer its screen, if it doesnât already.  That wonât help with the clear-screen call less is currently making, but it might reduce the tearing effect.

The same thing is happening with something like âls -lR /â.  The only difference is that you can easily see whatâs going on in the âman bashâ case, since the content remains static.

Another way to see it is âvim /etc/sshd_configâ, then hold down Ctrl-L.
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