Here is the sample souce code using cocos2dx
var from = rubber.getPosition(),
rubberVec = cc.pSub(to, from),
rubberAng = cc.pToAngle(rubberVec),
rubberDeg = cc.RADIANS_TO_DEGREES(rubberAng),
length = cc.pLength(rubberVec) + (lengthAddon || 8);
rubber.setRotation(-rubberDeg);
rubber.setScaleX(-(length / rubber.getContentSize()
.width));
if (topRubber) {
rubber.setScaleY(1.1 - ((0.7 / this.slingRadius.max) * length));
this.slingRubber3.setRotation(-rubberDeg);
this.slingRubber3.setPosition(cc.pAdd(from, cc.p((length) * Math.cos(rubberAng), (length) * Math.sin(rubberAng))));
}
how to do this in phaser box2d