How can I programmatically change the background in Mac OS X?

Question

How would I go about programmatically changing the desktop background in Mac OS X? I\'d like to use python, but I\'m interested in any way possible. Could I hook up to Ter

Answer 1

There are a default collection of quality images in:

/Library/Desktop Pictures/

To automate the selection of one of these across all desktops, without a 3rd party dependency:

osascript -e 'tell application "System Events" to set picture of every desktop to "/Library/Desktop Pictures/Solid Colors/Stone.png"'

Answer 2

If you are doing this for the current user, you can run, from a shell:

defaults write com.apple.desktop Background '{default = {ImageFilePath = "/Library/Desktop Pictures/Black & White/Lightning.jpg"; };}'

Or, as root, for another user:

/usr/bin/defaults write /Users/joeuser/Library/Preferences/com.apple.desktop Background '{default = {ImageFilePath = "/Library/Desktop Pictures/Black & White/Lightning.jpg"; };}'
chown joeuser /Users/joeuser/Library/Preferences/com.apple.desktop.plist

You will of course want to replace the image filename and user name.

The new setting will take effect when the Dock starts up -- either at login, or, when you

killall Dock

[Based on a posting elsewhere, and based on information from Matt Miller's answer.]

Answer 3

I had this same question, except that I wanted to change the wallpaper on all attached monitors. Here's a Python script using appscript (mentioned above; sudo easy_install appscript) which does just that.

#!/usr/bin/python

from appscript import *
import argparse

def __main__():
  parser = argparse.ArgumentParser(description='Set desktop wallpaper.')
  parser.add_argument('file', type=file, help='File to use as wallpaper.')
  args = parser.parse_args()
  f = args.file
  se = app('System Events')
  desktops = se.desktops.display_name.get()
  for d in desktops:
    desk = se.desktops[its.display_name == d]
    desk.picture.set(mactypes.File(f.name))


__main__()

Answer 4

You can call "defaults write com.apple.Desktop Background ..." as described in this article: http://thingsthatwork.net/index.php/2008/02/07/fun-with-os-x-defaults-and-launchd/

The article also goes into scripting this to run automatically, but the first little bit should get you started.

You might also be interested in the defaults man pages: http://developer.apple.com/documentation/Darwin/Reference/ManPages/man1/defaults.1.html