UIImageView通过startAnimating方法，播放经过CGImage翻转后的图像无效

UIImageView通过startAnimating方法，播放经过CGImage翻转后的图像时，该图像全是原始图像，即旋转生成的UIImage的array在startAnimating无效。该怎么解决？

大家可以测试以下代码：

//TEST 
UIImageView* imageView = [[UIImageView alloc] initWithFrame:CGRectMake(30.0, 30.0, 50.0, 50.0)]; 
UIImage* image = [UIImage imageNamed:@"Image.png"]; 
UIImage* orientImage = [UIImage imageWithCGImage:image.CGImage scale:1.0 orientation:UIImageOrientationDownMirrored]; 

imageView.animationImages = [[NSArray alloc] initWithObjects:orientImage, orientImage, nil]; 
imageView.animationDuration = 0.3; 
imageView.animationRepeatCount = 10; 
[imageView startAnimating];

[self.view addSubview:imageView];

PS:这里的翻转不是旋转，是OrientationUpMirrored，就是水平翻转、左右方向换过来；这里说的动画，就是像UIImageView的startAnimating的精灵动画，不是UIView animation那种关键帧动画。

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首先，

imageView.animationImages = [[NSArray alloc] initWithObjects:orientImage, orientImage, nil];

你不觉得两个对象是一样的？

其次，
你这个

 [UIImage imageWithCGImage:image.CGImage scale:1.0 orientation:UIImageOrientationDownMirrored];

创建出来的UIImage是不是和原图一样呢？

翻转的动画为什么不用CoreAnimation来实现呢？不需要用UIImageView的startAnimating

CALayer *layer = [CALayer layer]
// ... set bounds, position, etc.
layer.contents = [UIImage imageNamed:@"image"].CGImage;

[self.view.layer addSubLayer:layer];

CAKeyFrameAnimation *transformAnim = [CAKeyFrameAnimation animWithKeyPath:@"transform.rotation.x"];
// ... set duration, beginTime, etc.
transformAnim.keyTimes = @[@(0.0), @(1.0)];
transformAnim.values = @[(0.0), @(M_PI / 2)];
[layer addAnimation:transformAnim forKey:@"transform.rotation.x"];