UIGestureRecognizer Will Not Rotate Sprite - Cocos2d - iphone

Question

Does anyone know why it will not rotate the sprite?
- (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
CGPoint center = CGPointMake(CGRectGetMidX([[touch view] bounds]), CGRectGetMidY([[touch view] bounds]));
CGPoint firstLocation = [touch previousLocationInView:[touch view]];
CGPoint location = [touch locationInView:[touch view]];
CGPoint currentTouchPoint = [[CCDirector sharedDirector] convertToGL:location];
CGPoint previousTouchPoint = [[CCDirector sharedDirector] convertToGL:firstLocation];
CGPoint line2Start = currentTouchPoint;
CGPoint line1Start = previousTouchPoint;
CGPoint line2End = CGPointMake(center.x + (center.x - line2Start.x), center.y + (center.y - line2Start.y));
CGPoint line1End = CGPointMake(center.x + (center.x - line1Start.x), center.y + (center.y - line1Start.y));
CGFloat a = line1End.x - line1Start.x;
CGFloat b = line1End.y - line1Start.y;
CGFloat c = line2End.x - line2Start.x;
CGFloat d = line2End.y - line2Start.y;
CGFloat line1Slope = (line1End.y - line1Start.y) / (line1End.x - line1Start.x);
CGFloat line2Slope = (line2End.y - line2Start.y) / (line2End.x - line2Start.x);
CGFloat degs = acosf(((a*c) + (b*d)) / ((sqrt(a*a + b*b)) * (sqrt(c*c + d*d))));
CGFloat angleInRadians = (line2Slope > line1Slope) ? degs : -degs;
[g setRotation:angleInRadians];
}
- (void)ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event
{
UIGestureRecognizer *recognizer;
[recognizer setState:UIGestureRecognizerStateEnded];
}
G is the sprite in [g setRotation:angleInRadians];
Then, when I add in this
[[touch view] setTransform:CGAffineTransformRotate([[touch view] transform], [grinder rotation])];
It rotates the entire scene! Any help, please?
Thank You!

Answer 1

Dude
below is the link for the ui-kit but it will work fine for cocos2d as well
You need to take care of the coordination system
1)For cocos2d origin is bottom left corner
2)For UIKit origin is upper left corner
"Rotate image by Dragging"
Hope This help You
Good Luck

Answer 2

in the init method pass the following code. this will create a gesture recognizer
UIRotationGestureRecognizer *rotationGesture =
[[UIRotationGestureRecognizer alloc] initWithTarget:self
action:#selector(handleRotate:)];
rotationGesture.delegate = self;
[myImageView addGestureRecognizer:rotationGesture];
[rotationGesture release];
this is the vent that will trigger
- (void)handleRotate:(UIRotationGestureRecognizer *)recognizer {
if(recognizer.state == UIGestureRecognizerStateBegan ||
recognizer.state == UIGestureRecognizerStateChanged)
{
recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform,
recognizer.rotation);
[recognizer setRotation:0];
}
}