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Comment by jefurii | Hacker News Reader

Emacs flickers? I've never noticed this, but I've only ever used it on Linux. Maybe it flickers in OSX?

Article author here. Check the emacs-devel thread: some people were able to repro the flickering and some couldn't. It appears to depend heavily on details of your machine.

I have two X1 Carbon 4th Gen machines, one running Goobuntu (basically Ubuntu 14.04 with a new kernel) and one running Ubuntu 16.10. They both flicker, but differently.

How do you describe this flicker effect? I've never seen it.

Black and white horizontal lines or misrendered text for a split second until a white blink rerenders the whole page. Happens somewhat frequently when I have heavy CPU load on a Linux laptop.

Are your fixes available in trunk?

Yep.

Thanks!!!

Perhaps using a compositing desktop manager mitigates it, since those are almost always vsync'd and double buffered.

Edit: Hm, no there is no synchronization between the WM and emacs in any way. So this can't be it.

It definitely flickers a bit when running in XQuartz.

(I hope this change doesn't make it run crappily in XQuartz! X-Windows programs that do double buffering draw to an offscreen buffer often perform really poorly, poorly enough that I'd definitely rather have the flicker, not least because I don't mind the flicker too much anyway.

(I assume a lot of them have a client-side pixmap that's written to manually, and then has to be sent over the network link. )

One of the advantages of using the X double buffer extension or XRender or something like that is you don't need to send raster image data over the network. You're still sending ordinary drawing commands, and it's the server that accumulates the results into a pixmap somewhere.

If it is slow for you, you can turn off the new stuff:

    (modify-frame-parameters nil '((inhibit-double-buffering . t)))

But why inhibit-double-buffering and not just the simple no-double-buffering?

There are only 3 variables with a "no-" prefix, but 30+ starting with "inhibit-"...

Would not surprise me one bit if the compositing is the cause rather than the "solution".

You may just be pure of soul. I don't see a lot of flickering on X either, but I don't get too use emacs there as much as I'd like, either.

Are you using Emacs inside a terminal?

The flicker happens only with graphical Emacs (and then only on Linux IIUC).

Same here, I've been using Emacs daily (and a lot) in X11 for almost 10 years now, and I've never experienced flickering.

Same question I was about to ask. I use emacs on Ubuntu every day and I don't remember it flickering. I wouldn't use it if it were. Well, maybe I'll look for another OS.

Ditto, stock 14.04 Trusty running Unity, and this was also true for Debian releases lenny through wheezy, and at least two very different hardware systems.

I do experience flickering, on both a desktop Fedora 22 system and a X1 carbon 4th gen system running OpenBSD 6.0. It is usually mostly noticeable in the fringe area as well as along the divider when splitting windows. Kuddos for OP, the patch does not seem trivial and it is a most welcome change.

Me too, I've used emacs on several different OSX computers in recent years and never seen any flicker.

I've noticed it, since like, forever. Its why I'm a vi guy.

But I must admit, this butter-smooth version of emacs sounds intriguing .. off to give it a try.

Nothing, on i3, and graphical. So it seems near-random.

The article is a discussion about X11.

I notice it using cider.

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