do an action if the image on a region doesn't change

you can use the onChange listener to do this, if you don't know how your image looks like:

def handler(event):
    print "the region changed:"+`event`

region.onChange(handler, 10)
region.observe(5)

This will observe the region for 5 seconds and execute the script that is defined in the handler() method if the region changes during that time

Thanks for your answer...But the fact is that I would do an action only if the region not change.
Is exists an onNotChange method ??

Could you give me an exemple please?

Nobody ??

I tried this code :

reg = myRegion

def pp(event):
    global toto
    toto = "change"
    print"change"

def fff():
    toto = "notChange"
    print "do my action"
    reg.onChange(pp)
    reg.observe(1)
    wait(4)
    if toto == "notChange":
        print"notChanged"

fff()

When my region isn't change, it works:
result :
do my action
notChanged

but when my region change, it doesn't work:
result:
do my action
change
notChanged

why does the code goes to "notChanged"

Thanks by advance for your answer

The following working code might help you...

# script: RegionAreaTest6, 01 June 2013
# Related to [Question #229825]: do an action if the image on a region doesn't change
# This Sikuli script monitors a screen area to detect change.

bigChange=False # a global variable set if a region changes

def changed(event): # this function runs if change is observed
        print "something changed in ", event.region
        global bigChange # set to true if this function runs
        bigChange=True
        print bigChange
        for ch in event.changes:
                ch.highlight(2) # highlight all changes
        sleep(1)
        for ch in event.changes:
                ch.highlight() # turn off the highlights
        event.region.stopObserver()

# now start watching a Chicago Transit Authority map of buses moving down streets
# http://ctabustracker.com/bustime/map/displaymap.jsp

print "Starting..."
myRegion=Region(200,250,500,500)
# adjust size of region examined, make area as small as reasonably possible to limit searching, analysis

#myRegion=Region(420,270,200,200) # an alternative region that is smaller
myRegion.highlight(3) # for illustrative purposes, not functionally necessary
wait(1)
myRegion.highlight(0) #remove highlight
wait(1)
print bigChange # value of the variable before starting the monitoring

myRegion.onChange(30, changed) # install 'changed' as the function to run if changes are discovered
myRegion.observe(30,background=True) # start observing for 30 seconds before proceeding
# Monitoring is now running.
# Next start a loop to check for changes in the monitored area...

myLimit=4
i = 0 # index for our loop
mycontinue = True
print "Starting mycontinue loop..."
while mycontinue:
    print bigChange
    if bigChange:
        print "Something just changed."
    else:
        print "No change yet."
        # Do some desired action here...
    i +=1 # increment index
    if i >=myLimit:
        mycontinue=False
    wait(5)

print "Leaving mycontinue loop..."

myRegion.stopObserver() #stops the observer

myRegion=Region(100,300,500,500)
myRegion.highlight(3)
wait(1)
print bigChange
exit(0)

Thank you, I tested your code it works well !
Have a nice sunday

Very old question but it was a top search result for this question.

This can be solved in a much simpler way with:

def CheckForChange(checkRegion,sleepTime):
    cap = capture(checkRegion)
    sleep(sleepTime)
    if checkRegion.exists(cap,0):
        print("Still exists, no change")
        return False
    else:
        print("No longer exists, reg changed")
        return True