IOS中方向更改后保存UIImageView的UIScrollView布局不正确

我已经设置了一个

uicrollview

，其中包含一个带有

UIImage

的

UIImageView

。我加载到图像视图中的UIImage的大小约为2300x1200，并且没有缩放

UIScrollView保存一个UIImageView，该视图设置为允许点击/双击放大和缩小图像。我有

示例的源代码可以是

问题
我遇到的问题是方向的改变。视图不再按预期和偏移进行布局

下载图像后（在我的示例中），我完成以下操作：

[self.mainImageView setImage:image];
self.mainImageView.frame = (CGRect){.origin=CGPointMake(0.0f, 0.0f), .size=image.size};

// Tell the scroll view the size of the contents
self.mainScrollView.contentSize = image.size;

[self setupScales];

self.mainScrollView.translatesAutoresizingMaskIntoConstraints = NO;
self.mainImageView.translatesAutoresizingMaskIntoConstraints = NO;

然后，我将比例尺设置如下：

// Set up the minimum & maximum zoom scales
CGRect scrollViewFrame = self.mainScrollView.frame;
CGFloat scaleWidth = scrollViewFrame.size.width / self.mainScrollView.contentSize.width;
CGFloat scaleHeight = scrollViewFrame.size.height / self.mainScrollView.contentSize.height;
CGFloat minScale = MIN(scaleWidth, scaleHeight);

self.mainScrollView.minimumZoomScale = minScale;
self.mainScrollView.maximumZoomScale = 1.0f;
self.mainScrollView.zoomScale = minScale;

[self centerScrollViewContents];

CGSize boundsSize = self.mainScrollView.bounds.size;
CGRect contentsFrame = self.mainImageView.frame;

if (contentsFrame.size.width < boundsSize.width) {
    contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
} else {
    contentsFrame.origin.x = 0.0f;
}

if (contentsFrame.size.height < boundsSize.height) {
    contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
} else {
    contentsFrame.origin.y = 0.0f;
}

self.mainImageView.frame = contentsFrame;

然后，我将按如下方式查看centerScrollViewContents：

// Set up the minimum & maximum zoom scales
CGRect scrollViewFrame = self.mainScrollView.frame;
CGFloat scaleWidth = scrollViewFrame.size.width / self.mainScrollView.contentSize.width;
CGFloat scaleHeight = scrollViewFrame.size.height / self.mainScrollView.contentSize.height;
CGFloat minScale = MIN(scaleWidth, scaleHeight);

self.mainScrollView.minimumZoomScale = minScale;
self.mainScrollView.maximumZoomScale = 1.0f;
self.mainScrollView.zoomScale = minScale;

[self centerScrollViewContents];

CGSize boundsSize = self.mainScrollView.bounds.size;
CGRect contentsFrame = self.mainImageView.frame;

if (contentsFrame.size.width < boundsSize.width) {
    contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
} else {
    contentsFrame.origin.x = 0.0f;
}

if (contentsFrame.size.height < boundsSize.height) {
    contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
} else {
    contentsFrame.origin.y = 0.0f;
}

self.mainImageView.frame = contentsFrame;

scrollView的左/右/上/下约束固定为0，而imageView没有手动创建的约束。我已尝试运行

willRotateToInterfaceOrientation

中的

self.main ScrollView needsUpdateConstraints

，但这没有任何区别

---

当选择第一个选项“图像缩放”，然后更改设备方向时，上述示例应用程序中也会出现同样的问题。我不确定什么是不正确的，似乎帧设置不正确。我尝试在不同的点运行setupScales，但这似乎并没有改变问题。

当帧更改时，滚动视图的contentSize似乎被重置。旋转完成后，我必须将其设置回图像大小

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation {
    // When the orientation is changed the contentSize is reset when the frame changes. Setting this back to the relevant image size
    self.mainScrollView.contentSize = self.mainImageView.image.size;
    // Reset the scales depending on the change of values
    [self setupScales];
}

我已经为将来需要的任何人建立了回购协议-