ActionScript 2.0 Language Reference - Adobe Help and Support

hitTest (BitmapData.hitTest method)
public hitTest(firstPoint:Point, firstAlphaThreshold:Number,
secondObject:Object, [secondBitmapPoint:Point],
[secondAlphaThreshold:Number]) : Boolean
Performs pixel-level hit detection between one bitmap image and a point, rectangle or other
bitmap image. No stretching, rotation, or other transformation of either object is considered
when doing the hit test.
If an image is an opaque image, it is considered a fully opaque rectangle for this method. Both
images must be transparent images to perform pixel-level hit testing that considers
transparency. When you are testing two transparent images, the alpha threshold parameters
control what alpha channel values, from 0 to 255, are considered opaque.
Availability: ActionScript 1.0; Flash Player 8
Parameters
firstPoint:Point - A point that defines a pixel location in the current BitmapData
instance.
firstAlphaThreshold:Number - The highest alpha channel value that is considered opaque
for this hit test.
secondObject:Object - A Rectangle, Point, or BitmapData object.
secondBitmapPoint:Point [optional] - A point that defines a pixel location in the second
BitmapData object. Use this parameter only when the value of secondObject is a
BitmapData object.
secondAlphaThreshold:Number [optional] - The highest alpha channel value that is
considered opaque in the second BitmapData object. Use this parameter only when the value
of secondObject is a BitmapData object and both BitmapData objects are transparent.
Returns
Boolean - A Boolean value. If there is a hit, returns a value of true; otherwise, false.
Example
The following example shows how to determine if a BitmapData object is colliding with a
MovieClip.
import flash.display.BitmapData;
import flash.geom.Point;
var myBitmapData:BitmapData = new BitmapData(100, 80, false, 0x00CCCCCC);
324 ActionScript classes