How to get Mac OS to split the desktop into thirds?

January 6, 2010 12:10 PM

How can I get Mac OS X to arrange windows so each occupies a third of the screen?

I have a 30" monitor. The most useful way to employ the space is to arrange three windows, each the full height of the screen, each one occupying 1/3rd the width of the screen. Is there any way to tell Mac OS to do this?

About a year ago, someone asked a similar question and got pointers to an Applescript and a software tool called TwoUp, both of which solve this problem beautifully for two windows rather than three. As far as I can tell from perusing the answers to that earlier question, a year ago there was no convenient way to automatically arrange things in equal thirds.

Has anyone made progress on this?

posted by dgrobinson to Computers & Internet (7 answers total)

Cinch?
posted by null terminated at 12:24 PM on January 6, 2010

(actually it looks like Cinch also works on only half the screen)
posted by null terminated at 12:25 PM on January 6, 2010

You can easily modify the previous applescript to make thirds:

Change these lines (32-33):

set bounds of window 1 to {0, menubarHeight, (screenWidth / 2), screenHeight}
set bounds of window 2 to {(screenWidth / 2), menubarHeight, screenWidth, screenHeight}

to:

set bounds of window 1 to {0, menubarHeight, (screenWidth / 3), screenHeight}
set bounds of window 2 to {(screenWidth / 3), menubarHeight, (screenWidth / 3) * 2, screenHeight}
set bounds of window 3 to {((screenWidth / 3) * 2), menubarHeight, screenWidth, screenHeight}

posted by Free word order! at 12:43 PM on January 6, 2010 [1 favorite]

Response by poster: Thanks, free world order. Your suggestion improves the state of play. The modified script does what I'm hoping for, when it works at all.

But it turns out to be a bit kludgy:

• It arranges three windows from the current app, so you can't use it to arrange, e.g., a word processor alongside two web browser windows.
• It generates an error if fewer than three windows are open in the current app.
• When I try to use it with firefox, which would be my preferred typical use case, I get an error message:

  Error: -43. File firefox-bin wasn't found.

posted by dgrobinson at 1:25 PM on January 6, 2010

Best answer: You could try to get SizeUp to do it... Set a 10 inch (in pixels) "margin" between the left and right splitscreen windows, and set "Center" to resize the window to 100% of the monitor height and 33% of the monitor width. Then if you send a window to center, it'll end up in the margin between the left and right windows. (I don't know if this works in practice.)
posted by sentient at 9:47 PM on January 6, 2010

Response by poster: Thanks, sentient! The sizeup "center" command makes the window exactly the right size for my task. (I still do end up needing to drag it into place, but that's easy once the window is perfectly sized to occupy a third of the screen.)
posted by dgrobinson at 11:42 AM on January 7, 2010

Cool! So, do you have to deal with the left and right windows manually (er, via dragging) at all in terms of placement or resizing to thirds? Just curious.
posted by sentient at 1:16 PM on January 7, 2010