ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with motion tweens
Motion object names
Flash Player 9 and later, Adobe AIR 1.0 and later, requires Flash CS3 or later
In the previous case, Flash automatically generated the name __motion_Symbol1_2 for the Motion object. It attached
the prefix __motion_ to the display object name. Thus, the automatically generated name is based on the instance
name of the target object of the motion tween in Flash. The duration property of the Motion object indicates the total
number of frames in the motion tween:
__motion_Symbol1_2.duration = 200;
By default, Flash automatically names the display object instance whose motion tween is copied, if it does not already
have an instance name.
When you reuse ActionScript created by Flash in your own animation, you can keep the name that Flash automatically
generates for the tween or you can substitute a different name. If you change the tween name, make sure that you
change it throughout the script.
Alternately, in Flash you can assign a name of your choosing to the target object of the motion tween. Then create the
motion tween and copy the script. Whichever naming approach you use, make sure that each Motion object in your
ActionScript code has a unique name.
Describing the animation
Flash Player 9 and later, Adobe AIR 1.0 and later, requires Flash CS3 or later
The addPropertyArray() method of the MotionBase class adds an array of values to describe every tweened
property.
Potentially the array contains one array item for every keyframe in the motion tween. Often some of these arrays
contain fewer items than the total number of keyframes in the motion tween. This situation occurs when the last value
in the array does not change for the remaining frames.
If the length of the array argument is greater than the duration property of the Motion object, addPropertyArray()
adjusts the value of the duration property accordingly. It does not add keyframes for the properties that were
previously added. The newly added keyframes persist for the extra frames of the animation.
The x and y properties of the Motion object describe the changing position of the tweened object as the animation is
running. These coordinates are the values that are most likely to change in every keyframe, if the position of the display
object changes. You can add additional motion properties with the addPropertyArray() method. For example, add
the scaleX and scaleY values if the tweened object is resized. Add the scewX and skewY values if it is skewed. Add the
rotationConcat property if it rotates.
Use the addPropertyArray() method to define the following tween properties:
x horizontal position of the transformation point of the object in the coordinate space of its parent
y vertical position of the transformation point of the object in the coordinate space of its parent
z depth (z-axis) position of the transformation point of the object in the coordinate space of its parent
scaleX horizontal scale as a percentage of the object as applied from the transformation point
scaleY vertical scale as a percentage of the object as applied from the transformation point
Last updated 6/6/2012
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