UI的变形

• transform:形变属性，能完成的功能：平移、缩放、旋转

• 利用动画来实现

   [UIView animateWithDuration:2.0 animations:^{
  
       // 缩放
        self.tempView.transform = CGAffineTransformMakeScale(0.5, 0.5);
  
        // 平移
        self.tempView.transform = CGAffineTransformMakeTranslation(-100, 100);
  
        // 旋转objc
        self.tempView.transform = CGAffineTransformMakeRotation(-M_PI_4);
  
        CGAffineTransform translation = CGAffineTransformMakeTranslation(-100, 100);
  
        CGAffineTransform scaleTranslation = CGAffineTransformScale(translation, 0.5, 0.5);
  
        CGAffineTransform rotateScaleTranslation = CGAffineTransformRotate(scaleTranslation, M_PI_2);
  
        self.tempView.transform = rotateScaleTranslation;
   }];
  

• 有一种情况是根据上一个状态来变形的
• eg 根据tempView的上一个状态 加上缩放 1/4
• 注意 1/4 可以写M_PI_4

 self.tempView.transform = CGAffineTransformRotate(self.tempView.transform, M_PI_4);

• 清空transform，以前的平移、缩放、旋转都会消失

     self.tempView.transform = CGAffineTransformIdentity;