User Guide

418 Working with Geometry

Finding the distance between two points

You can use the distance() method of the Point class to find the distance between two

points in a coordinate space. For example, the following code finds the distance between the

registration points of two display objects,

circle1 and circle2, in the same display object

container:

import flash.geom.*;

var pt1:Point = new Point(circle1.x, circle1.y);

var pt2:Point = new Point(circle2.x, circle2.y);

var distance:Number = Point.distance(pt1, pt2);

Translating coordinate spaces

If two display objects are in different display object containers, they may be in different

coordinate spaces. You can use the

localToGlobal() method of the DisplayObject class to

translate the coordinates to the same (global) coordinate space, that of the Stage. For example,

the following code finds the distance between the registration points of two display objects,

circle1 and circle2, in the different display object containers:

import flash.geom.*;

var pt1:Point = new Point(circle1.x, circle1.y);

pt1 = circle1.localToGlobal(pt1);

var pt2:Point = new Point(circle1.x, circle1.y);

pt2 = circle2.localToGlobal(pt2);

var distance:Number = Point.distance(pt1, pt2);

Similarly, to find the distance of the registration point of a display object named target from

a specific point on the Stage, you can use the

localToGlobal() method of the DisplayObject

class:

import flash.geom.*;

var stageCenter:Point = new Point();

stageCenter.x = this.stage.stageWidth / 2;

stageCenter.y = this.stage.stageHeight / 2;

var targetCenter:Point = new Point(target.x, target.y);

targetCenter = target.localToGlobal(targetCenter);

var distance:Number = Point.distance(stageCenter, targetCenter);