src/pixi/geom/Circle.js
function Circle(x, y, radius)
{
    /**
     * @property x
     * @type Number
     * @default 0
     */
    this.x = x || 0;

    /**
     * @property y
     * @type Number
     * @default 0
     */
    this.y = y || 0;

    /**
     * @property radius
     * @type Number
     * @default 0
     */
    this.radius = radius || 0;
}
function Circle(x, y, radius)
{
    /**
     * @property x
     * @type Number
     * @default 0
     */
    this.x = x || 0;

    /**
     * @property y
     * @type Number
     * @default 0
     */
    this.y = y || 0;

    /**
     * @property radius
     * @type Number
     * @default 0
     */
    this.radius = radius || 0;
}
function Circle ( x , y , radius ) { /**
     * @property x
     * @type Number
     * @default 0
     */ this . x = x || 0 ; /**
     * @property y
     * @type Number
     * @default 0
     */ this . y = y || 0 ; /**
     * @property radius
     * @type Number
     * @default 0
     */ this . radius = radius || 0 ; }
The Circle object can be used to specify a hit area for displayobjects

@class Circle
@constructor
@param x {Number} The X coord of the upper-left corner of the framing rectangle of this circle
@param y {Number} The Y coord of the upper-left corner of the framing rectangle of this circle
@param radius {Number} The radius of the circle
The Circle object can be used to specify a hit area for displayobjects