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A Python/PyObjC port of Fabian Canas's command-line mirror tool from http://mirror-displays.googlecode.com/. Demonstrates use of the Quartz Display Services to control display mirroring, and also shows how PyObjC handles "pass-by-reference" parameters. The LaunchAgent plist defines a job that runs at the loginwindow, running mirrortool.py to ena…
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Disabled</key>
<false/>
<key>Label</key>
<string>com.foo.displaymirroring</string>
<key>LimitLoadToSessionType</key>
<array>
<string>LoginWindow</string>
</array>
<key>ProgramArguments</key>
<array>
<string>/Library/Tools/mirrortool.py</string>
<string>on</string>
</array>
<key>RunAtLoad</key>
<true/>
</dict>
</plist>
#!/usr/bin/python
# encoding: utf-8
"""
mirrortool.py
Created by Greg Neagle on 2013-06-05.
A PyObjC port of Fabian Canas's command-line mirror tool from
http://mirror-displays.googlecode.com/
See:
https://developer.apple.com/library/mac/#documentation/graphicsimaging/reference/Quartz_Services_Ref/Reference/reference.html
https://developer.apple.com/library/mac/#documentation/graphicsimaging/Conceptual/QuartzDisplayServicesConceptual/Introduction/Introduction.html#//apple_ref/doc/uid/TP40004316
"""
import sys
import os
import Quartz
def main():
# default mode if none specified
mode = 'query'
# get our own name
toolname = os.path.basename(sys.argv[0])
# get any mode that may have been passed at the command line
if len(sys.argv) > 1:
mode = sys.argv[1].lower()
# make sure the mode is one we know about
if not mode in ['toggle', 'on', 'off', 'query', 'help']:
mode = 'help'
if mode == 'help':
print """Usage: %s [toggle|on|off|query|help]
toggle: Toggle mirroring mode
on: Turn mirroring on
off: Turn mirroring off
query: Return mirroring state to stdout (default)
help: Print this message and exit.""" % toolname
exit(0)
# we currently know only how to handle two attached displays
max_displays = 2
# get active display list
# CGGetActiveDisplayList:
# Provides a list of displays that are active (or drawable).
(err, active_displays,
number_of_active_displays) = Quartz.CGGetActiveDisplayList(
max_displays, None, None)
if err:
print >> sys.stderr, "Error in obtaining active display list: %s" % err
exit(-1)
# get online display list
# CGGetOnlineDisplayList:
# Provides a list of displays that are online
# (active, mirrored, or sleeping).
(err, online_displays,
number_of_online_displays) = Quartz.CGGetOnlineDisplayList(
max_displays, None, None)
if err:
print >> sys.stderr, "Error in obtaining online display list: %s" % err
exit(-1)
# make sure we have the right number of displays.
# currently that number is exactly 2.
if number_of_online_displays > 2:
print >> sys.stderr, (("Cannot handle more than two displays. "
"%s displays detected.")
% number_of_online_displays)
exit(-1)
if number_of_online_displays < 2:
print >> sys.stderr, (("Can't mirror fewer than two displays. "
"%s displays detected.")
% number_of_online_displays)
exit(-1)
if number_of_online_displays == 2:
if online_displays[0] == Quartz.CGMainDisplayID():
secondary_display = online_displays[1]
else:
secondary_display = online_displays[0]
if mode == 'query':
if number_of_active_displays == 2:
print 'Display mirroring is off'
else:
print 'Display mirroring is on'
exit(0)
# begin display configuration
(err, config_ref) = Quartz.CGBeginDisplayConfiguration(None)
if err:
print >> sys.stderr, "Error with CGBeginDisplayConfiguration: %s" % err
exit(-1)
if mode == 'toggle':
if number_of_active_displays == 2:
# currently unmirrored
err = Quartz.CGConfigureDisplayMirrorOfDisplay(
config_ref, secondary_display, Quartz.CGMainDisplayID())
else:
# currently mirrored
err = Quartz.CGConfigureDisplayMirrorOfDisplay(
config_ref, secondary_display, Quartz.kCGNullDirectDisplay)
if mode == 'on':
if number_of_active_displays == 2:
# currently unmirrored
err = Quartz.CGConfigureDisplayMirrorOfDisplay(
config_ref, secondary_display, Quartz.CGMainDisplayID())
if mode == 'off':
if number_of_active_displays != 2:
# currently mirrored
err = Quartz.CGConfigureDisplayMirrorOfDisplay(
config_ref, secondary_display, Quartz.kCGNullDirectDisplay)
if err:
print >> sys.stderr, "Error configuring displays: %s" % err
exit(-1)
# apply the changes
err = Quartz.CGCompleteDisplayConfiguration(
config_ref, Quartz.kCGConfigurePermanently)
if err:
print >> sys.stderr, ("Error with CGCompleteDisplayConfiguration: %s"
% err)
exit(-1)
if __name__ == '__main__':
main()
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