Check Rotation in iphone SDk - iphone

Question

In my app, i used SMRotatory wheel for rotation. It is working fine as rotation regarding.
But i want to detect that rotation is clockwise or anti-clockwise??
//My code is as follow:
- (BOOL)continueTrackingWithTouch:(UITouch*)touch withEvent:(UIEvent*)event
{
CGFloat radians = atan2f(container.transform.b, container.transform.a);
// NSLog(#"rad is %f", radians);
CGPoint pt = [touch locationInView:self];
float dx = pt.x - container.center.x;
float dy = pt.y - container.center.y;
float ang = atan2(dy,dx);
float angleDifference = deltaAngle - ang;
// NSLog(#"%f",angleDifference);
if (angleDifference>=0) {
//NSLog(#"positive");
[[NSUserDefaults standardUserDefaults]setValue:#"positive" forKey:#"CheckValue"];
}
else
{
// NSLog(#"negative");
[[NSUserDefaults standardUserDefaults]setValue:#"negative" forKey:#"CheckValue"];
}
container.transform = CGAffineTransformRotate(startTransform, -angleDifference);
bg.transform=CGAffineTransformRotate(startTransform, -angleDifference);
return YES;
}

Answer 1

Try something like this:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint currentTouch1=[touch locationInView:self.superview];
CGPoint currentTouch2=[touch previousLocationInView:self.superview];
CGFloat x = currentTouch2.x - currentTouch1.x;
CGFloat y = currentTouch2.y - currentTouch1.y;
CGFloat dist = sqrtf(x*x + y*y);
CGFloat cx = currentTouch1.x - self.superview.bounds.size.width / 2;
CGFloat cy = currentTouch2.y - self.superview.bounds.size.height / 2;
CGFloat cdist = sqrtf(cx*cx + cy*cy);
CGFloat angle = atan2(dist, cdist);
//NSLog(#"%f",angle);
CGFloat radians = atan2f(super.transform.b, super.transform.a);
mDegrees = radians * (180 / M_PI);
if (mDegrees < 0.0)
{
mDegrees+=360;
}
NSLog(#"Angle is = %f",angle); //positive is clockwise, negative is counterclockwise
CGAffineTransform transform = CGAffineTransformRotate(self.transform, angle);
self.transform = transform;
touch1 = currentTouch1;
touch2 = currentTouch2;
}