Detecting When Mouse Leaves Movie by
senocular and kirupa | 11 September 2008
One thing about previous versions of ActionScript was
that you could never tell when the user no longer had his or
her mouse over the Flash movie. This made it hard for people
to know whether or not the user is still interacting with
their movie or if they've given up and moved on to something
more interesting. This was especially a problem for custom
cursors where, if the user moved the cursor off the Flash
movie, the custom cursor would still remain in the Flash
movie not moving while the real cursor could be seen moving
around everywhere else.
ActionScript 3 now allows you to detect when the mouse
has left the flash movie using the stage's
To see this in action, hover your mouse over the following Flash movie:
Notice the custom mouse cursor follows your mouse as long
as you are within the movie's boundaries. Once your mouse
leaves your movie's boundaries, the cursor fades out of view.
Pretty cool, ehh?
Download Source File To
see how this was done, download the Flash CS3 source file
from the following location:
Download and extract the above file and open it in Flash
CS3. Much of what you see should be pretty straightforward,
but let's look at the contents in greater detail.
Examining the File Our
movie is made up of two main things. The first is the cursor
movie clip, and the second is the code. Let's look at the
easy part - the cursor movie clip:
[ your custom cursor has the instance name cursor ]
Your cursor movie clip is nothing more than a white
circle with a ridiculously large stroke. You can look inside
the movie clip to see the basic fade out animation, but I
won't discuss how that is created or setup in this tutorial.
The only thing to note about this movie clip is that its
instance name is cursor.
Your cursor movie clip relies on code to tell it to
follow your mouse and disappear when the mouse leaves the
stage, so let's look at the code.
Below, you will see all of the code that powers
The Start function is what gets called first when your
movie is run. Notice the Start function call at the very
bottom of our code. The Start function is responsible for
registering two events with their corresponding event
First you setup the MOUSE_LEAVE event on your stage to
call cursorHide when your mouse leaves the stage. Next, you
setup the MOUSE_MOVE event on your stage to call
cursorFollow when your mouse is moved around the stage.
The cursorHide function gets called when your
event is fired, and that event is fired only when your mouse
cursor leaves your stage. Any thing you want your movie to
to do when the mouse leaves the stage, you add the code for
In this case, when the cursorHide function gets
called, I play the small fading transition that starts at
the frame labeled fadeOut inside your cursor movie clip:
[ inside the cursor movie clip, you'll find the fade out
This transition is responsible for fading your cursor out
gradually when your mouse cursor leaves the movie's
The final function we will look at is cursorFollow.
function is tied to your MOUSE_MOVE event, so each time your
mouse cursor moves around your movie, this function
will get called.
The first thing I do is ensure the the first frame of the
cursor movie clip is displayed, for I don't want to display
it in its faded out state.
The exact position of the cursor movie clip is determined
by your stage's mouseX and mouseY properties:
By setting my cursor movie clip's x and y position to the
stage's mouseX and mouseY properties, I ensure that the
custom cursor follows the mouse around. The final line is
the updateAfterEvent call:
Because we are moving our cursor movie clip each time the
MOUSE_MOVE event fires,
you will find yourself calling the cursorFollow function
more frequently than allowed by your frame rate. This will
cause fast and rapid movements to seem like they are
lagging. Calling updateAfterEvent on your evtMouseEvent object forces
Flash to redraw the stage as quickly as needed independent
of the frame rate.
Conclusion That's all
there is to this. The new addition in AS3 has been the
MOUSE_LEAVE event attached
to your stage. You now have the ability to listen for mouse
events on the stage itself, and one thing you can do now
that you couldn't before is detect when the mouse leaves the
movie and deal with that as you wish.