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

Another way to programmatically change the desktop wallpaper is to simply point the wallpaper setting at a file. Use your program to overwrite the file with the new design, then restart the dock: killall Dock.

The following depends on Xcode, lynx and wget, but here's how I automatically download and install a monthly wallpaper on Mountain Lion (shamelessly stolen and adapted from http://ubuntuforums.org/showthread.php?t=1409827) :

#!/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/opt/local/bin
size=1440
dest="/usr/local/share/backgrounds/wallpaperEAA.jpg"
read -r baseurl < <(lynx -nonumbers -listonly -dump 'http://www.eaa.org/en/eaa/aviation-education-and-resources/airplane-desktop-wallpaper' | grep $size) &&
wget -q "$baseurl" -O "$dest"
killall Dock

Dump it into /etc/periodic/monthly/ and baby, you got a stew goin!

Answer 2

To add to Matt Miller's response: you can use subprocess.call() to execute a shell command as so:

import subprocess
subprocess.call(["defaults", "write", "com.apple.Desktop", "background", ...])

Answer 3

You could also use py-appscript instead of Popening osascript or use ScriptingBridge with pyobjc which is included in 10.5 but a bit more cumbersome to use.

Answer 4

From python, if you have appscript installed (sudo easy_install appscript), you can simply do

from appscript import app, mactypes
app('Finder').desktop_picture.set(mactypes.File('/your/filename.jpg'))

Otherwise, this applescript will change the desktop background

tell application "Finder"
    set desktop picture to POSIX file "/your/filename.jpg"
end tell

You can run it from the command line using osascript, or from Python using something like

import subprocess

SCRIPT = """/usr/bin/osascript<<END
tell application "Finder"
set desktop picture to POSIX file "%s"
end tell
END"""

def set_desktop_background(filename):
    subprocess.Popen(SCRIPT%filename, shell=True)

Answer 5

Building on dF.'s answer, you could do it with Apple Script without Finder and you can do it for multiple desktops.

To set the wallpaper for desktop i (desktop numbers start at 1):

tell application "System Events"
    set currDesktop to item i of desktop
    set currDesktop's picture to "image_path"
end tell

This is what I ended up doing (in Python):

SET_DESKTOP_IMAGE_WRAPPER = """/usr/bin/osascript<<END
tell application "System Events"
{}
end tell
END"""

SET_DESKTOP_IMAGE = """
set currDesktop to item {idx} of desktops
set currDesktop's picture to "{image_path}"
"""

def set_wallpapers(images):
    """ images is an array of file paths of desktops """

    script_contents = ""
    for i, img in enumerate(images):
        idx = i+1
        script_contents += SET_DESKTOP_IMAGE.format(idx=idx, image_path=img)

    script = SET_DESKTOP_IMAGE_WRAPPER.format(script_contents)
    subprocess.check_call(script, shell=True)

Sometimes, the desktop images don't appear immediately. I don't know why this happens, but restarting the dock fixes it. To do that from python:

subprocess.check_call("killall Dock", shell=True)

By the way, you can get the number of desktops on the system using this AppleScript code:

tell application "System Events"
    get the number of desktops
end tell

you can use that with subprocess.check_output to get the output

Answer 6

The one-line solution for Mavericks is:

osascript -e 'tell application "Finder" to set desktop picture to POSIX file "/Library/Desktop Pictures/Earth Horizon.jpg"'