Ubuntu consistency changes

[Daniel Stone]

On Thu, Oct 13, 2005 at 08:09:08AM +0200, John Nilsson wrote:
> On Thu, 2005-10-13 at 00:11 +0100, Sitsofe Wheeler wrote:
> > When Ubuntu prompts for a password, the password window has no
> > border. This makes it feel very strange and does not draw attention
> > to it (focus appears to be elsewhere looking at titlebar colours).
> 
> I've been playing with the code for this. My plan was to have a full
> screen blur effect behind the password window. But I've got a little
> problem: Using gdk_pixbuf_get_from_drawable() to get the whole screen
> from the server is a _VERY_ slow operation.
> 
> Does anyone have a better idea? I think that the operation can be
> accelerated with SHM but that requires the server and client on the same
> computer, which is kind of ugly.
> 
> I noticed that there was code copied that would shade the screen
> instead, is anyone working on that?

So, there are a couple of issues here.

Firstly, SHM helps, but you'll have to read the image out of the video
card's framebuffer, which is incredibly slow.  That's before you
transfer it.

Secondly, assuming you want to do the compositing client-side, you need
to do colour transformations of 1024*768, 1600*1200, or however many,
pixels.  This hurts.  Doing this quickly in software is a non-trivially
difficult task.

Thirdly, you need to upload the image again.

This pretty much eliminates any kind of gradual fade: you'll need to do
that with a very good compositing manager if you want it.  The only
reason xscreensaver's fade works is because it does a gamma fade, which
is both quick and very well supported.

Cheers,
Daniel
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