[compiz] Zoom enhancements

David Reveman davidr at novell.com
Thu Apr 19 12:55:25 PDT 2007

On Sun, 2007-04-15 at 22:53 +0200, Kristian Lyngstøl wrote:
> I'll be working on zoom during Google summer of code, to get it to
> work better with existing accessibility software. Basicly get it to
> communicate with tools like Orca.
> Because this relies on input enabled zoom, there are some issues I
> like to clear up before I start. I don't want to directly base my work
> on any of the two publicly available zoom plugins. This means I'll be
> creating a new plugin, using as much of the work done in the existing
> zoom plugins as possible. Though zoom is a fairly straight-forward
> plugin in general.
> The plugin will initialy use the same technique Beryl's input enabled
> zoom uses, but the idea is to design it so it can use IR if(and when)
> it's available. That shouldn't be too hard, luckily. I also have some
> ideas of how to have "follow focus" input enabled zoom even without
> IR. The idea is to allow several methods of doing roughly the same
> things, based on what's available.
> So far, this project is very much in the planning phase, coding isn't
> scheduled to start until May 28th. As such, I have not yet gotten
> familiar with Orca, and the technical details of how I'll get Orca and
> Compiz to cooperate have yet to be defined. I do intend to keep this
> entierly in the plugin-code, and if possible, I'll use dbus. One of
> the main goals will be mainstream inclusion (Which is why I'm bringing
> this up now), regardless of what exactly we end up calling mainstream.
> I'm interested in comments from the people who've worked most with the
> existing zoom plugins. I know the ideal solution would be to "wait for
> IR", but that's just not an option. Like I said, I'll be doing the
> next best thing: Write the plugin so it'll support IR when it's
> available. I have a rough idea of how I'll do this and I don't think
> it'll be too much work.
> David; I know you have some opinions on the matter. I've also heard
> rumours of there beeing an IR-enabled zoom plugin, if that's true, I'd
> like to have a look at it if possible. Or just a few pointers of what
> you see an IR enabled zoom plugin doing that the non-IR equivalent
> can't, beyond the most obvious.

I've got some core compiz modifications that allow plugins like zoom,
clone and scale to use input transformations but it's some pretty nasty
hacks and just for testing and demo purposes. More significant changes
needs to be made to compiz for input transformations support to be
integrated properly.

I'm reluctant to release those hacks as I'm afraid that some people will
be more interested improving those hacks than help out with getting a
more proper solution in place.

> Also, I've followed the IR thread on the X.org list, but it seems to
> have gone silent. Have anyone done any work on IR since then that I'm
> missing?

I've got a local input transformation patch for the server that seem to
be in pretty good shape, I just need to fix a few more things in it.
I'll send it to the xorg list once I've had time to do that.

Thanks for posting your plans to the list. Integrating compiz zoom
functionality with external apps and accessibility frameworks makes a
lot of sense. I'll be able to provide some more feedback and suggestions
related to this later on.

- David

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