UIPinchGestureRecognizer捏合手勢

• alloc
• initWithTarget
• imageView.transform = CGAffineTransformScale(iView.transform, pinch.scale, pinch.scale);
  // 對圖像視圖對象進(jìn)行矩陣變換計算并賦值
  // CGAffineTransformScale通過縮放的方式產(chǎn)生一個新的矩陣
  //P1：原來的矩陣
  //P2：x方向上的縮放比例
  //P3：y方向上的縮放比例
• <UIGestureRecognizerDelegate>協(xié)議方法
• shouldRecognizeSimultaneouslyWithGestureRecognizer是否可以同時響應(yīng)兩種手勢

UIRotationGestureRecognizer旋轉(zhuǎn)手勢

• alloc
• initWithTarget
• imageView.transform = CGAffineTransformRotate(iView.transform, rot.rotation);

具體使用：讓一個圖像視圖支持縮放和旋轉(zhuǎn)手勢
主要代碼如下

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    UIImage* image = [UIImage imageNamed:@"icon1"];
    UIImageView* iView = [[UIImageView alloc]initWithImage:image];
    iView.frame = CGRectMake(100, 200, 150, 150);
    //打開圖像視圖支持交互的開關(guān)
    iView.userInteractionEnabled = YES;
    [self.view addSubview:iView];
    //創(chuàng)建捏合手勢對象
    _pinchGes = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAct:)];
    [iView addGestureRecognizer:_pinchGes];
    //創(chuàng)建旋轉(zhuǎn)手勢
    _rotGes = [[UIRotationGestureRecognizer alloc]initWithTarget:self action:@selector(rotAct:)];
    [iView addGestureRecognizer:_rotGes];
    
    _rotGes.delegate = self;
    _pinchGes.delegate = self;
}

//協(xié)議方法：是否可以同時響應(yīng)兩個手勢
-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
    return YES;
}
-(void)rotAct:(UIRotationGestureRecognizer *)rot{
    UIImageView* iView = (UIImageView *)rot.view;
    //計算旋轉(zhuǎn)的變換矩陣并且賦值
    iView.transform = CGAffineTransformRotate(iView.transform, rot.rotation);
    //旋轉(zhuǎn)角度清零
    rot.rotation = 0;
}

-(void)pinchAct:(UIPinchGestureRecognizer *)pinch{
    //獲取監(jiān)控視圖圖像
    UIImageView* iView = (UIImageView *)pinch.view;
    //對圖像視圖對象進(jìn)行矩陣變換計算并賦值
    //CGAffineTransformScale通過縮放的方式產(chǎn)生一個新的矩陣
    //P1：原來的矩陣
    //P2：x方向上的縮放比例
    //P3：y方向上的縮放比例
    iView.transform = CGAffineTransformScale(iView.transform, pinch.scale, pinch.scale);
    
    //將縮放值歸位為單位值，由于響應(yīng)函數(shù)是在每個瞬間都調(diào)用的（不管手指是否有滑動）
    //如果不歸零，縮放后保持手指觸屏位置不變時，圖片也會一直按照上一次縮放的比例繼續(xù)縮放。
    //scale=1原來的大小
    pinch.scale = 1;
}