Kwin vs Compiz (sorta)

[keljaden]

Okay, I know in gnome I use compiz, but KDE has Kwin. In addition to having pretty much the same desktop effects as compiz, does Kwin also use the GPU to render and run DE as opposed to it being CPU. I have read articles giving me convoluted information on this and I want to have this down.

How do Kwin and Compiz differ/whats the same? (both technical code/hardware usage wise, and effects).

Also, whats this beryl thing? From my understanding on it, the beryl peeps just gave up and started to work making compiz better.

[lovinglinux]

How do Kwin and Compiz differ/whats the same? (both technical code/hardware usage wise, and effects).

I couldn't think about living without Compiz, which made me switch to KDE before Gnome 3 ruins my life. Now I'm using Kwin and I couldn't be happier. It is a lot simpler to configure than Compiz and has all the effects I need (related to productivity). For instance, you can change a lot of window options from the window itself, while in Compiz I had to open the settings manager and go through several options in the Window Rule, Place and Scale plugins.

Also, whats this beryl thing? From my understanding on it, the beryl peeps just gave up and started to work making compiz better.

Beryl was a fork of Compiz that has been re-merged with it to form Compiz Fusion. See http://en.wikipedia.org/wiki/Beryl_%28window_manager%29

[keljaden]

so what makes Kwin different than compiz other than a different settings manager? Does Kwin still use the GPU for all the effects as opposed to the CPU?

[Zorael]

A window manager handles windows. It decides which window has focus, moves them around, resizes them, minimizes/maximizes, etc.

A window decorator draws decorations (borders and titlebars including buttons) around windows.

A window compositor adds a buffering layer to which applications write, including the window manager and decorator. Their output may then be transformed before it is showed on the screen. This is where the cubes, expose effects, scaling, transparency, contorting, etc comes in.

Compiz is a window manager and a window compositor, but it needs a window decorator to work. Else you'll end up with no window borders; just search the forums and see how many hits 'compiz window borders' has. The compiz-gnome package I believe comes with a decorator that's compatible with the normal GNOME window themes. Emerald is an alternative decorator but it uses its own themes. I don't know if compiz-kde is around anymore, but it used to come with kde-window-decorator, which is/was a buggy/completely broken decorator compatible with KWin themes.

Metacity is GNOME's standard window manager and decorator. It has no compositing abilities so no 3D effects.

KWin is the KDE window manager decorator and compositor. The compositing features can be turned on and off, in System Settings -> Desktop -> Desktop Effects and via the Alt+Shift+F12 hotkey.

As lovinglinux noted, Beryl was a fork of Compiz. Old and superseded.

I don't know exactly how Compiz relates to Compiz Fusion anymore. It used to be that Fusion was Compiz with extra plugins (largely ported from Beryl when merging the projects), but then there was an effort to make it all just Compiz again, and now I remember reading an announcement that they want to develop them separately again.

[3Miro]

KDE Settings Manager -> Desktop you can change all the Kwin options and settings.

Kwin - composition = CPU rendering, i.e. very simple.

Kwin + composition = GPU rendering and the ability to use effects.

Kwin and Compiz may use similar libraries and methodology, but Kwin is specifically build for KDE and has abilities that compiz can never have (such as preview of minimized windows). Kwin is also smoother and takes less resources. Compiz is basically a hack on top of whatever environment it is sitting on, a beautiful hack, but a hack never the less.

Kwin has most of the same effects as Compiz.

[c00lwaterz]

interesting. can kwins run on gnome?

[3Miro]

interesting. can kwins run on gnome?

I don't think so, you can try:

sudo apt-get install kubuntu-desktop

to install KDE and Kwin and then

kwin --replace

but I don't think it will work. In any case, under Gnome you will be better off with compiz, since unlike kwin it was build to service Gnome.

[Zorael]

In case you don't want to pull the whole Kubuntu distro, KWin is in the kde-window-manager package. Installing it will pull the basic KDE libraries as dependencies but leave out Kubuntu art and default apps.

[SmSpillaz]

KDE Settings Manager -> Desktop you can change all the Kwin options and settings.

Kwin - composition = CPU rendering, i.e. very simple.

Kwin + composition = GPU rendering and the ability to use effects.

Kwin and Compiz may use similar libraries and methodology, but Kwin is specifically build for KDE and has abilities that compiz can never have (such as preview of minimized windows).

Wrong. It's possible to implement this in compiz (I've done it), but we don't implement it because it breaks minimization. I believe KWin also removed it for this reason

Kwin is also smoother and takes less resources. Compiz is basically a hack on top of whatever environment it is sitting on, a beautiful hack, but a hack never the less.

KWin is a window manager. Compiz is a window manager. I don't see how either of them could fit into the category of being a "hack".

Both of them follow EWMH, which is the freedesktop.org spec on how a window manager should work. Window managers are not supposed to be built around the desktop environment - they can certainly use some shared libraries that the desktop environment uses, but in order to follow any standards they need to use window hints as per EWMH.

In fact, KWin uses X11 window properties (something you are supposed to use in EWMH) to implement functionality like thumbnails in the plasma taskbar (or the 'slide' effect on menus). All they do is define the properties of the effect and it's up to the compositor to implement it. In fact, we implement them all really trivially in compiz already.

Kwin has most of the same effects as Compiz.

It is true that KWin is catching up and probably has 80% feature parity, but the implementation details are far different and there are certain things that KWin wont implement.

[krazyd]

Wrong. It's possible to implement this in compiz (I've done it), but we don't implement it because it breaks minimization. I believe KWin also removed it for this reason

Nope, kwin has this.
edit: I may have misunderstood 3Miro's statement. What I mean is that kwin caches the window state at the time of minimisation to provide previews. It doesn't continue rendering to a minimised window's pixmap.

It is true that KWin is catching up and probably has 80% feature parity, but the implementation details are far different and there are certain things that KWin wont implement.

I'm intrigued.. what are these features?