Move your application’s windows between spaces

I puzzled for a few hours over this the other night — it’s something that used to work in VirtueDesktops, and for some reason I just assumed it no longer functioned under Mac OS X 10.5. Aside from an embarrassing bout of forgetting to get the window number properly, this turned out to be remarkably simple.

Prerequisites

You’ll need a copy of the CGSPrivate header in your project.

How to

Simply use the following code, where ibo_window is an Interface Builder outlet to an NSWindow in your XIB file:

CGSWindowID windowId = (CGSWindowID)[ibo_window windowNumber];
// The following integer represents the space you want to move the window to - the array is not zero-based - Space 1 == 1, Space 2 == 2, etc
NSInteger spaceToMoveTo = 2;
// Window count can be more than one, but for this example we're using a single window
NSInteger windowCount = 1;
// Now for the magical call:
CGSMoveWorkspaceWindowList(_CGSDefaultConnection(), &amp;windowId, windowCount, spaceToMoveTo);

// If you want to check which space a window is on, simple use the following code:
NSInteger windowId = -1;  
CGSGetWindowWorkspace(_CGSDefaultConnection(), windowId, &amp;workspaceID);
NSLog(@"Your window is now on space %i", windowId);

Easy, huh? I’m pretty sure this won’t work across processes (that’s why all the old desktop managers insert code into the running Dock application — it’s one of the only applications that has permission to muck about with other application’s windows). You should also probably try to intercept any errors thrown by the CGS* methods, but I’ll leave that as an exercise to you, gentle reader.

∞
Posted: December 5, 2008 at 22:57
Tagged: Cocoa, Programming

Comments

Great tip. I was wondering how to do this. I have a question for you though. I’m a developer and have just recently started looking into OSX development and came across your hyperspaces app. I’m curious as to what you wrote it in, and whether that was a design decision, or if you were forced into that language because of what you were trying to do on the operating system. Thanks!

Posted by Chris on January 7, 2009 at 07:49

Hi Chris,
Hyperspaces is written in Objective-C, using the Cocoa framework. There’s a sprinkling of the older Carbon framework in my hotkey helper application, only because it’s not currently possible to set global hotkeys directly using Cocoa.
There are also a few straight C functions — these are mainly around the private SPIs that I use to access information about the current state of the user’s workspaces (just like the one in this post).
I gave some thought to using an alternative language earlier on such as Ruby using the MacRuby bridges, but if you’re developing on the mac you’d be kind of silly to use anything but Cocoa. UI toolkits/frameworks such as Trolltech’s Qt and other “universal” UI toolkits generally look out of place and don’t respond in quite the same way as a native Cocoa application.
I guess I could have used Objective-C++ as the language, but I don’t really know C++ all that well to start with. I guess there were a few places where I was “forced” to use straight C, but given the nature of Objective-C you’d be hard pressed to avoid it in even the most straight-laced of applications.
Does that answer your question?

Posted by Tony Arnold on January 9, 2009 at 17:08

Tony: thank you, thank you, thank you. This is exactly what we needed to solve a major problem with Stainless (our multi-process browser à la Google Chrome) and Spaces. You will definitely get a credit in our app.

Posted by Danny Espinoza on February 5, 2009 at 13:42

@Danny — not a problem at all — I’m glad it came to be some use! I have a few other tricks up my sleeve I’m writing up at the moment, so let me know if there’s anything else you’re stuck on.

Posted by Tony Arnold on February 8, 2009 at 19:09

If I try to interact with the code block (scroll, select text), then it becomes mostly transparent.
Using Chrome 5.0.366.2 on Windows 7 (oh the horror)

Posted by Rowan Lewis on April 3, 2010 at 22:26

Ugh, way to go Chrome. This is what happens when Google half asses their implementation. Looks like the -webkit-mask-image is getting screwed up — I’ll look for a fix.
It seems to me that shit like this shouldn’t happen when Google are using WebKit, but noooo — they have to muck about and make it NotQuiteWebKit. Dicks.
</rant>

Posted by Tony Arnold on April 3, 2010 at 22:45

Tony, thanks very much for this pointer. Is there also a call to create one or a list of newly opened windows in a designated Space?

Posted by tribalvibes on March 8, 2011 at 14:53

A call to create a new Space? You can adjust the number of rows/columns via the scripting bridge framework. Controlling where individual windows isn’t possible without private API usage right now, but you can also set the application bindings via the scripting bridge. I hope that helps.

Posted by Tony Arnold on March 8, 2011 at 16:35

Sorry, this conversation has finished.

This post is a bit old now, so I've closed the conversation. If you're keen to keep talking about it, please email me directly.