Drag Rotate UIImageView by touch
- by rockstardev
I have an UIImageView that is a subview of an UIView. I'm trying to create a drag rotate effect with the UIImageView similar to spinning a bottle but I'm having trouble calculating the radians to rotate the image by. My code below seems like it should work because I've seen a similar calculation in Flash examples. Can anyone shed some light on what I'm doing wrong?
Thanks.
This is the code contained in my image view subclass:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
lastLocation = [touch locationInView:[self superview]];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
CGPoint location = [touch locationInView:[self superview]];
CGFloat xDisplacement = location.x - lastLocation.x;
CGFloat yDisplacement = location.y - lastLocation.y;
CGFloat rad = atan2f(yDisplacement,xDisplacement);
self.transform = CGAffineTransformMakeRotation(rad);
}
