Bad Flickering Scrolling Up

[dylnmc]

I didn't see an issue about this, and I don't know how easy it would be to fix. This is a really awesome plugin, but in rxvt-unicode, the flicking when pressing <c-b> or <c-u> makes the screen flicker every line.

This plugin works superbly in termite and works pretty well in gnome-terminal, however. It even works well in xterm. I just prefer rxvt-unicode most times.

I don't suppose there is anything you can do about this issue, but I thought I would post it.

Cheers,
dylnmc

[toejough]

same problem in iterm. I've noticed that this doesn't occur for me if I have a horizontal split, even if it's small.

[yuttie]

@dylnmc Hmm, I cannot reproduce the issue...
I installed rxvt-unicode of version 9.21 on my Gentoo linux and tried , , etc.

Does flickering occur when you continuously repeat or ?
Since this plugin just repeats input of or in essence, I think flickering will occur when you hold down these keys. If you find flickering doesn't occur, then there may be some room for this plugin to improve the problem.

[yuttie]

@dylnmc @toejough Now I can reproduce the issue with Vim, but I have no problem with Neovim.
The flickering occurs not only on urxvt but also on st.

Holding down <C-y> does not make any flickering, so I will investigate this issue when I have time.

[toejough]

maybe I'll finally have to update to neovim. This is by far the best scrolling plugin I've found 🥇

[dylnmc]

I was using neovim and vim for a while. Due to some complications, I have been using only vim mostly for a few months now. Although I sometimes pop in and use neovim when I am feeling spiffy, I usually stick with vim. I have found that some of the trickier things simply work in vim (but there are still a few edge cases in neovim that I can't be bothered with).

I am glad to hear that it works in neovim.

[amarqueslee]

I’ve submitted a pull request which I believe will fix this issue. It works for me, would anyone else mind to give my patched version a shot and let me know if it works for them too?

[yuttie]

@amarqueslee Thank you for your contribution!
I tried your branch and confirmed that it solved the problem for me.

Your patch includes two major changes:

1. Using redraw (efc7959#diff-c2074d217c7c8d15486f419d95226276R71), and
2. Running just one persistent tick thread.

Firstly, I think this flikering issue is actually solved by the first change.
Applying only the first change, I found that flickering dissapears on my environment.
@amarqueslee, could you try it on your environment?
If it works for you and others too, I want you to create a separate pull request that just inserts redraw appropriately.
Then, I will merge the new pull request for this issue.

Secondly, we need to improve the other change for another issue of this plugin.
Thanks to your patch, I found that my original code redundantly starts a new tick thread whenever comfortable_motion#flick() is called, which causes unnatural acceleration.
The second change actually fixes the problem by maintaining only a single persistent tick thread.
However, it also introduces constant CPU usage even when a user doesn't use a vim.
I think we can improve the patch by stopping a tick thread when it is not needed.
This problem should be discussed in another issue.

[amarqueslee]

Ok. I:

• Confirm that this issue is resolved with a call to redraw only
• Have updated the PR for this issue to only call redraw
• Have created a new issue to represent the remaining work that needs to be done around fixing up tick threads
• Will implement the changes you suggested and submit a further pull request under the separate issue

Thanks @yuttie for testing the fix and for your suggestions and feedback.

[yuttie]

I close this issue because #21 has been merged and it fixed the problem.

[dylnmc]

Amazing! It's like an entirely different plugin now 😆

Maybe I will encorporate this into my daily workflow now 💃