【IOS】使用手势对UIImageView进行缩放、旋转和移动

因为项目需要，需要对图片进行一些操作。本着拿来主义的原则~上网找了方法。

但是发现网上很多实现，要么过于复杂，要么不够完善。

终于找到一篇比较好的文章。

参考文章： http://apluck.iteye.com/blog/1781607

代码：

[cpp] view plaincopy

1. // 添加所有的手势  
2. - (void) addGestureRecognizerToView:(UIView *)view  
3. {  
4.     // 旋转手势  
5.     UIRotationGestureRecognizer *rotationGestureRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotateView:)];  
6.     [view addGestureRecognizer:rotationGestureRecognizer];  
7.       
8.     // 缩放手势  
9.     UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchView:)];  
10.     [view addGestureRecognizer:pinchGestureRecognizer];  
11.       
12.     // 移动手势  
13.     UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panView:)];  
14.     [view addGestureRecognizer:panGestureRecognizer];  
15. }  
16.   
17. // 处理旋转手势  
18. - (void) rotateView:(UIRotationGestureRecognizer *)rotationGestureRecognizer  
19. {  
20.     UIView *view = rotationGestureRecognizer.view;  
21.     if (rotationGestureRecognizer.state == UIGestureRecognizerStateBegan || rotationGestureRecognizer.state == UIGestureRecognizerStateChanged) {  
22.         view.transform = CGAffineTransformRotate(view.transform, rotationGestureRecognizer.rotation);  
23.         [rotationGestureRecognizer setRotation:0];  
24.     }  
25. }  
26.   
27. // 处理缩放手势  
28. - (void) pinchView:(UIPinchGestureRecognizer *)pinchGestureRecognizer  
29. {  
30.     UIView *view = pinchGestureRecognizer.view;  
31.     if (pinchGestureRecognizer.state == UIGestureRecognizerStateBegan || pinchGestureRecognizer.state == UIGestureRecognizerStateChanged) {  
32.         view.transform = CGAffineTransformScale(view.transform, pinchGestureRecognizer.scale, pinchGestureRecognizer.scale);  
33.         pinchGestureRecognizer.scale = 1;  
34.     }  
35. }  
36.   
37. // 处理拖拉手势  
38. - (void) panView:(UIPanGestureRecognizer *)panGestureRecognizer  
39. {  
40.     UIView *view = panGestureRecognizer.view;  
41.     if (panGestureRecognizer.state == UIGestureRecognizerStateBegan || panGestureRecognizer.state == UIGestureRecognizerStateChanged) {  
42.         CGPoint translation = [panGestureRecognizer translationInView:view.superview];  
43.         [view setCenter:(CGPoint){view.center.x + translation.x, view.center.y + translation.y}];  
44.         [panGestureRecognizer setTranslation:CGPointZero inView:view.superview];  
45.     }  
46. }  

这样只需要简单调用

[cpp] view plaincopy

1. [self addGestureRecognizerToView:view];    
2.    
3. //如果处理的是图片，别忘了  
4. [imageView setUserInteractionEnabled:YES];    
5. [imageView setMultipleTouchEnabled:YES];   

大功告成。

具体使用一下：

在.h文件里边定义变量

[cpp] view plaincopy

1. @interface YourViewController : UIViewController<UIGestureRecognizerDelegate>  
2. {  
3.     CGFloat lastScale;  
4.     CGRect oldFrame;    //保存图片原来的大小  
5.     CGRect largeFrame;  //确定图片放大最大的程度  
6. }  

然后在viewDidLoad里面加上

[cpp] view plaincopy

1. - (void)viewDidLoad  
2. {  
3.     [super viewDidLoad];  
4.   
5.     showImgView = [[UIImageView alloc] initWithFrame:<span class="s1">CGRectMake</span>(<span class="s2">0</span>, <span class="s2">0</span>, 320, 480)];  
6.     [showImgView setMultipleTouchEnabled:YES];  
7.     [showImgView setUserInteractionEnabled:YES];  
8.     [showImgView setImage:[UIImage imageNamed:@"1.jpg"]];  
9.       
10.     oldFrame = showImgView.frame;  
11.     largeFrame = CGRectMake(0 - screenSize.width, 0 - screenSize.height, 3 * oldFrame.size.width, 3 * oldFrame.size.height);  
12.       
13.     [self addGestureRecognizerToView:showImgView];  
14.     [self.view addSubview:showImgView];  

这样就实现了

但是，这样是不够的。

因为里边的缩放和移动等没有做相应的判断。

因为代码很简洁，所以扩展也非常方便。

我修改了缩放的代码，增加了限制，其他的类似

[cpp] view plaincopy

1. // 处理缩放手势  
2. - (void) pinchView:(UIPinchGestureRecognizer *)pinchGestureRecognizer  
3. {  
4.     UIView *view = pinchGestureRecognizer.view;  
5.     if (pinchGestureRecognizer.state == UIGestureRecognizerStateBegan || pinchGestureRecognizer.state == UIGestureRecognizerStateChanged) {  
6.         view.transform = CGAffineTransformScale(view.transform, pinchGestureRecognizer.scale, pinchGestureRecognizer.scale);  
7.         if (showImgView.frame.size.width < oldFrame.size.width) {  
8.             showImgView.frame = oldFrame;  
9.             //让图片无法缩得比原图小  
10.         }  
11.         if (showImgView.frame.size.width > 3 * oldFrame.size.width) {  
12.             showImgView.frame = largeFrame;  
13.         }  
14.         pinchGestureRecognizer.scale = 1;  
15.     }  
16. }  

这样就好了。保证了图片的最大和最小比例。