根据iPhone SDK中的触摸旋转图像

Question

I want to rotate an image smoothly according to the touch of the user. The user moves touch as he wants to move the image. He also moves the touch circularly. How do I do this?

Answer 1

IT MAY HELP TO U ....

 -(IBAction)rotateImage:(id)sender{

                 UIRotationGestureRecognizer *rotationRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)];
                 [rotationRecognizer setDelegate:self];
                 ["YOUR IMAGEVIEW" addGestureRecognizer:rotationRecognizer];
                 [rotationRecognizer release];  

                                 }

ROTATE

  CGFloat lastRotation;
    CGFloat angle;
         -(void)rotate:(UIRotationGestureRecognizer *)sender{

[self.view bringSubviewToFront:[(UIRotationGestureRecognizer*)sender view]];

if([(UIRotationGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {

    lastRotation = 0.0;
    return;
}

CGFloat rotation = 0.0 - (lastRotation - [(UIRotationGestureRecognizer*)sender rotation]);
//angle = rotation;
CGAffineTransform currentTransform = [(UIPinchGestureRecognizer*)sender view].transform;
CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform,rotation);

[[(UIRotationGestureRecognizer*)sender view] setTransform:newTransform];

lastRotation = [(UIRotationGestureRecognizer*)sender rotation];
angle = lastRotation;
      }

Answer 2

{
//Add rotate gesture to your imageView

 UIRotationGestureRecognizer *rotateGesture=[[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotateGestureAction:)];
[imageView addGestureRecognizer:rotateGesture];
[rotateGesture release];

  [imageView setUserInteractionEnabled:YES];
  [imageView setMultipleTouchEnabled:YES];

}

- (void)rotateGestureAction:(UIRotationGestureRecognizer *)rotate 
 {
    UIImageView *imageView=(UIImageView *)rotate.view;

float prevRotation=0.0;
if (rotate.state == UIGestureRecognizerStateBegan) 
{
    prevRotation = 0.0;
} 
float thisRotate = rotate.rotation - prevRotation;
prevRotation = rotate.rotation;
yourImageView.transform = CGAffineTransformRotate(self.view.transform, thisRotate);
}

Answer 3

If you are asking for rotation image using single finger movement. This is what you are seeking for.

Answer 4

-(void)rotateImage:(id)sender 
{
    if([(UIRotationGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) 
    {
    lastRotation = 0.0;
    return;
}

CGFloat rotation = 0.0 - (lastRotation - [(UIRotationGestureRecognizer*)sender rotation]);

CGAffineTransform currentTransform = [(UIRotationGestureRecognizer*)sender view].transform;

CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform,rotation);

[[(UIRotationGestureRecognizer*)sender view] setTransform:newTransform];

lastRotation = [(UIRotationGestureRecognizer*)sender rotation];

}