使用手势对UIImageView进行缩放、旋转和移动

[cpp] view plain copy

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

这样只需要简单调用

[cpp] view plain copy

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

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 plain copy

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

修改了缩放的代码，增加了限制，其他的类似

[cpp] view plain copy

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。

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