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Xplain: Explaining X11 for the rest of us

magcius.github.io

11–20 of 21 posts

Re: Xplain: Explaining X11 for the rest of us

#11
Great read, especially enjoyed learning about why IE6 did that thing it did[0].

I'm not sure why I enjoy reading things like this. I have no intention of getting into X development or graphics programming for that matter but it was fun read nonetheless.

[0] http://www.mrdoob.com/lab/javascript/effects/ie6/

Re: Xplain: Explaining X11 for the rest of us

#12
post #7
post #6

I haven't really gone through X11 before, but the API really is terrible. How have we managed to hang onto this monstrosity for so long? I get people have a fondness for something that has held up for so long, but the huge complexity and difficulty of hardware acceleration means it's time to throw it out. http://magcius.github.io/xplain/article/x-basics.html Head over there and drag the kitten around to see why. Now…

X has had a feature, called backing store, to get around that since the 80s. Individual windows can request backing store, and there's an option you can set in xorg.conf to enable backing store for all windows. X11 actually anticipated a future of composited windows, each with their own separate buffer to draw into, well before its rivals -- due in no small part to being intended to run on much more advanced hardware…

The issue is the added complexity of having to enable backing stores and the multiple code paths. It's not about "how much we can glue inside X11 until it sort of works sometimes".

You can throw out 95% of X11 and most developers would be much happier, bugs would go down, and everything would still work fine.

Re: Xplain: Explaining X11 for the rest of us

#14
post #6

I haven't really gone through X11 before, but the API really is terrible. How have we managed to hang onto this monstrosity for so long? I get people have a fondness for something that has held up for so long, but the huge complexity and difficulty of hardware acceleration means it's time to throw it out. http://magcius.github.io/xplain/article/x-basics.html Head over there and drag the kitten around to see why. Now…

To see what?

Note that the window under it, with its white background, actually has a setTimeout when it repaints:

https://github.com/magcius/xplain/blob/gh-pages/src/article-...

Without that, even in a slow JavaScript implementation, you can barely see the white background.

As I explain in the article, this is entirely because of memory pressure limits of the 80s. This is what Windows 7 does too. And in a modern environment (compositing manager), windows do get their own backing pixel memory.

Re: Xplain: Explaining X11 for the rest of us

#15
post #12
post #7

Earlier quoted context omitted.

X has had a feature, called backing store, to get around that since the 80s. Individual windows can request backing store, and there's an option you can set in xorg.conf to enable backing store for all windows. X11 actually anticipated a future of composited windows, each with their own separate buffer to draw into, well before its rivals -- due in no small part to being intended to run on much more advanced hardware…

The issue is the added complexity of having to enable backing stores and the multiple code paths. It's not about "how much we can glue inside X11 until it sort of works sometimes". You can throw out 95% of X11 and most developers would be much happier, bugs would go down, and everything would still work fine.

Yes, that's why Wayland was invented. 95% of X11 is not necessary anymore, but it was in the 80s.

Re: Xplain: Explaining X11 for the rest of us

#17
post #4

Pardon the honesty, but this too academic, and not tasked based, for a 'rest of us' style. Further reading: OK, this is an X developer's guide. You should call it that. It will help developers find it and stop the average Joe who wants to run a remote app on his local display from trying to use the wrong guide.

Yeah, I guess now that I think about it I didn't think too much about that tagline.

Re: Xplain: Explaining X11 for the rest of us

#19
post #6

I haven't really gone through X11 before, but the API really is terrible. How have we managed to hang onto this monstrosity for so long? I get people have a fondness for something that has held up for so long, but the huge complexity and difficulty of hardware acceleration means it's time to throw it out. http://magcius.github.io/xplain/article/x-basics.html Head over there and drag the kitten around to see why. Now…

> but the API really is terrible

Then use a different one, like xcb. Or even abandon it altogether and use Wayland.

> How have we managed to hang onto this monstrosity for so long?

Because it (largely) works.

And 99% of people don't ever have to come into contact with it.

> Now your average Linux desktop builds a lot on X11 to get it to perform how it does now

If you mean "builds a lot on" you mean "ignores the vast majority of outdated features of", then yes.

> but all this effort is a huge waste

Not really. A lot of the stuff replacing X11 cruft had to be implemented anyway, and the weird X11 hacks, well, they were just what was needed at the time to get work done. No use in crying over spilt milk.

> Just compare it to something like Apple's UIKit or Android's layouts

What would be the point in that? They serve very different purposes.

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