IOS手势识别，捏合，旋转，轻扫等

ref:http://blog.csdn.net/rechard_chen/article/details/51769972

//点按手势的创建，这里需要实现响应事件的方法
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tap)];

tap.delegate = self;
// 添加到需要手势的视图
[_imageView addGestureRecognizer:tap];

// 长按 手势的创建
// 长按手势时间比较长，可以根据手势的状态states，设置功能；
UILongPressGestureRecognizer*longPres = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longPress:)];

[_imageView addGestureRecognizer:longPres];

// 添加 轻扫手势， 轻扫默认的方向：向右
// 一个轻扫手势只能支持一个方向
// 一个控件可以添加很多手势
UISwipeGestureRecognizer*swipeLeft = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)]; //在响应方法中，可以根据轻扫的方向（direction）做事情；
//这是一个枚举类型，上下左右；
swipeLeft.direction= UISwipeGestureRecognizerDirectionLeft;
[_imageView addGestureRecognizer:swipeLeft];

UISwipeGestureRecognizer*swipeRight = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];

swipeRight.direction= UISwipeGestureRecognizerDirectionRight;
[_imageView addGestureRecognizer:swipeRight];

//拖拽手势的创建
UIPanGestureRecognizer *pan = [[ UIPanGestureRecognizer alloc ] initWithTarget : self action : @selector (pan:)];

[_imageView addGestureRecognizer:pan];

- ( void )pan:( UIPanGestureRecognizer *)pan
{
// 获取手指偏移量，相对于最原始位置的偏移量
CGPoint transP = [pantranslationInView:_imageView];
// 改 imageView 形变
_imageView.transform= CGAffineTransformTranslate(_imageView.transform, transP.x, transP.y);
// 复位，相对于上一次
[pansetTranslation:CGPointZeroinView:_imageView];
}

//在使用模拟器模拟一下两个手势的时候，需要按住option + 鼠标左键实现两个手指点击（反向运动）；shift + option + 鼠标左键（同向运动）；

//旋转手势的创建
UIRotationGestureRecognizer *rotation = [[ UIRotationGestureRecognizer alloc ] initWithTarget : self action :@selector (rotation:)];
rotation.delegate= self;
[_imageView addGestureRecognizer:rotation];

//方法的实现
- ( void )rotation:( UIRotationGestureRecognizer *)rotationGestureRecognizer
{
_imageView . transform = CGAffineTransformRotate ( _imageView . transform , rotationGestureRecognizer. rotation);
// 复位
rotationGestureRecognizer.rotation = 0;
}

//捏合缩放手势的实现
UIPinchGestureRecognizer *pinch = [[ UIPinchGestureRecognizer alloc ] initWithTarget : self action : @selector(pinch:)];

pinch.delegate= self;
[_imageView addGestureRecognizer:pinch];

//响应方法的实现
- ( void )pinch:( UIPinchGestureRecognizer *)pinch
{
// 获取相对于最原始的缩放比例
CGFloat scale = pinch.scale;
// x,y ， x 表示宽度缩放多少， y 表示高度缩放
_imageView . transform = CGAffineTransformScale ( _imageView . transform , scale, scale);
// 复位
pinch.scale = 1;
}

手势代理方法的实现：
//当View需要同时实现多个手势的时候。需要返回YES；
- ( BOOL )gestureRecognizer:( UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:( UIGestureRecognizer *)otherGestureRecognizer;

//可以控制点击区域是否实现手势；通过UITouch获取当前点击的点，通过坐标控制区域
- ( BOOL )gestureRecognizer:( UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:( UITouch *)touch;