calc cross coord (as3)

crosscord_sketch.as

    /**
     * return coordinate of crossing two lines defined by {x1; y1}, {x2; y2}
     * @param l1
     * @param l2
     * @return
     */
    private static function getCrossCoord(coef1:Object, coef2:Object):Point {
        var a1:Number = coef1.a;
        var b1:Number = coef1.b;
        var c1:Number = coef1.c;
        var a2:Number = coef2.a;
        var b2:Number = coef2.b;
        var c2:Number = coef2.c;

        var cross:Point = new Point(
                (c2 * b1 - c1 * b2) / (a1 * b2 - a2 * b1),
                (c2 * a1 - c1 * a2) / (b1 * a2 - b2 * a1)
        );
        return cross;
    }

    /**
     * return the free coefficient of base line formula
     * @param x1
     * @param y1
     * @param x2
     * @param y2
     * @return
     */
    private static function getLineCoefs(x1:Number, y1:Number, x2:Number, y2:Number):Object {
        return {
            a:y2 - y1,
            b:x1 - x2,
            c:(y1 * x2) - (x1 * y2)
        };
    }