two places at the same time

April 9, 2007 7:01 AM

Is it possible to selectively mirror windows to a second screen (projector) on Mac OS X?

When I do presentations I don't like to use a mirrored desktop because I have notes and things to myself on my screen. Many presentation apps (e.g., Keynote) are smart about projecting and will show different stuff on the second screen. I'd like to be able to selectively mirror particular windows onto the second screen. Like, if I'm showing off a database app, I'd like that mirrored, but not other things. Is this possible? Thanks.

posted by rbs to computers & internet (7 comments total)

You can drag a window onto the second screen (just turn off mirroring).
posted by reeddavid at 7:22 AM on April 9, 2007

Sounds like you need Spanning Doctor.
posted by sourwookie at 7:38 AM on April 9, 2007

I've never seen anything like this. As far as the OS is concerned, the basic unit is "the whole screen" -- either the whole screen is the same on both displays (mirroring on) or the whole screen is different (mirroring off).

You can get a hardware setup with a second screen in front of you so you can see what the audience sees. Or, more economically, you can print your notes and work from paper.
posted by jjg at 7:40 AM on April 9, 2007

In the case of Keynote or Powerpoint, the software app itself is doing the "mirroring" by keeping the content in the windows in synch. Havent heard of a solution that works for any general window.

This does remind me though that most remote presentation apps do allow you to "share" or not share certain parts of your screen. So your users can only see, say, one of your windows and not the ones with personal notes. But here again, software is involved.
posted by vacapinta at 8:03 AM on April 9, 2007

You might consider a screen-sharing tool like WebEx or GoToMeeting. You can selectively share only certain applications for example, or you can share your entire desktop.

Of course, this requires that you use two different computers (the one hooked up to the projector is a client of the presentation you're sharing) and that both have access to the network.

Also, these tools aren't free.
posted by Jeff Howard at 8:12 AM on April 9, 2007

Thanks for the responses so far. The issue isn't that I can't see what they see, just that I only want them to see a subset of what I see. Like, say I'm doing a demo and I want to project one of the windows I'm using, but not all of them. Right now, if I mirror, they see everything. If I span, the window moves over to the projector, but not on my screen anymore. Using a splitter and a second monitor would be a grande pain. From the responses, though, it seems as though nobody's written an app that will selectively duplicate a window in another part of the virtual screen.
posted by rbs at 12:47 PM on April 9, 2007

I'm not on a dual monitor Mac at the moment and can't try any of this out, but you might try getting something like Desktop Manager (which allows you to have multiple virtual desktops on one system a.k.a. most *nix desktop systems). I believe this app allows you to have applications displayed in more than one virtual desktop at a time.

You'd then want to configure a "Presentations" virtual desktop and convince the virtual desktop software to place it only on your projected display. Launch an app, set it to display on both the "Main" and "Presentations" virtual desktops, and you're set.

I'll try this tomorrow, since it seems like a handy thing to be able to do...
posted by jmcmurry at 7:26 PM on April 9, 2007