iOS开发：使用手势UIGestureRecognizer对图像进行缩放、移动、旋转操作

- (void)viewDidLoad {
[super viewDidLoad];

UIPinchGestureRecognizer *pinchRecognizer = [[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scale:)] autorelease];
[pinchRecognizer setDelegate:self];
[self.view addGestureRecognizer:pinchRecognizer];

UIRotationGestureRecognizer *rotationRecognizer = [[[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotate:)] autorelease];
[rotationRecognizer setDelegate:self];
[self.view addGestureRecognizer:rotationRecognizer];

UIPanGestureRecognizer *panRecognizer = [[[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)] autorelease];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[panRecognizer setDelegate:self];
[canvas addGestureRecognizer:panRecognizer];

UITapGestureRecognizer *tapProfileImageRecognizer = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapped:)] autorelease];
[tapProfileImageRecognizer setNumberOfTapsRequired:1];
[tapProfileImageRecognizer setDelegate:self];
[canvas addGestureRecognizer:tapProfileImageRecognizer];
}

// 缩放
-(void)scale:(id)sender {

if([(UIPinchGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {
_lastScale = 1.0;
}

CGFloat scale = 1.0 - (_lastScale - [(UIPinchGestureRecognizer*)sender scale]);

CGAffineTransform currentTransform = photoImage.transform;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, scale, scale);

[photoImage setTransform:newTransform];

_lastScale = [(UIPinchGestureRecognizer*)sender scale];
[self showOverlayWithFrame:photoImage.frame];
}

// 旋转
-(void)rotate:(id)sender {

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

_lastRotation = 0.0;
return;
}

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

CGAffineTransform currentTransform = photoImage.transform;
CGAffineTransform newTransform = CGAffineTransformRotate(currentTransform,rotation);

[photoImage setTransform:newTransform];

_lastRotation = [(UIRotationGestureRecognizer*)sender rotation];
[self showOverlayWithFrame:photoImage.frame];
}

// 移动
-(void)move:(id)sender {

CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:canvas];

if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {
_firstX = [photoImage center].x;
_firstY = [photoImage center].y;
}

translatedPoint = CGPointMake(_firstX+translatedPoint.x, _firstY+translatedPoint.y);

[photoImage setCenter:translatedPoint];
[self showOverlayWithFrame:photoImage.frame];
}