Compiz default Application Switcher (Alt+Tab) is difficult to use

[chombee]

I originally filed this as a big report, which I thought was the right
thing to do, but it got rejected as not a bug:
https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/220227

Binary package hint: compiz

The default Alt+Tab switcher ("Application Switcher") in Ubuntu/compiz
is badly designed from a usability point of view, and differs from the
alt-tab in metacity. Since the application switcher is a default feature
and fundamental feature of the desktop, I think this issue is important.

In metacity: when you alt+tab, previews of all windows are shown at
once, if necessary organised into multiple rows and shrunk to fit them
all on screen. The window previews stay in a fixed position, and as you
press Tab the highlight moves from one to the next. Because the windows
stay still and the selection moves it is easy to spot the window you are
moving to and to judge how far you are from it, and know when you have
arrived at it. Also, you immediately understand how many windows there
are, can quickly see how many windows of a given application there are,
and can easily see when your selection has moved past the last window
and back to the first. Basically, it works very well and should be taken
as an example of the correct behaviour.

In compiz:

1. A fixed maximum number of window previews appear on screen at once,
regardless of how many windows there are. This makes it impossible to
see how many windows you have open, or how many windows of a given app,
without cycling through them all and counting. And it means you don't
easily know when you have cycled back to the first window, you have to
recognise it when it comes around again.

2. The selection stays still, while the windows move. This makes it
difficult to find the window you want with your eyes, because they are
moving. It promotes a slow mode of use where you press tab, wait for the
next window preview to focus, look at it and decide what it is, then
either release alt or press tab again. (As opposed to just finding the
window you want with your eyes because they are all on screen, then
quickly pressing tab the right number of times to move the selection to
it.)

In both aspects compiz should be changed to match metacity.

Another problem with Alt-Tab in compiz is caused by the highlighting of
the selected window. If the user is quickly alt-tabbing back and forth
between two windows it causes the screen to flash disturbingly,
especially if one of the two windows is maximised. Alt-Tab has two use
cases:

1. The user is searching for a window to switch to. In this case the
window previews and window highlighting are useful.

2. The user knows which window is the previous one, and just wants to
switch to that by pressing Alt+Tab once, for example when switching
repeatedly between two windows by just pressing alt+tab quickly. In this
case the window previews and highlights serve no purpose.

There should be a brief delay before drawing the window previews and
highlights. If alt is still held after half a second, say, they will be
drawn. This would allow very quick switching to the previous window
without the screen flashing.