iOS - UIImageView - 如何处理 UIImage 图像方向答案

【问题标题】：iOS - UIImageView - how to handle UIImage image orientationiOS - UIImageView - 如何处理 UIImage 图像方向
【发布时间】：2012-02-13 11:55:21
【问题描述】：

是否可以设置UIImageView 来处理图像方向？当我将UIImageView 设置为具有方向RIGHT 的图像时（它是相机胶卷中的照片），图像向右旋转，但我想以正确的方向显示它，因为它是拍摄的。

我知道我可以旋转图像数据，但可以做得更优雅吗？

【问题讨论】：

标签： ios uiimageview uiimage orientation

【解决方案1】：

如果我理解，您想要做的是忽略 UIImage 的方向？如果是这样，那么您可以这样做：

UIImage *originalImage = [... whatever ...];

UIImage *imageToDisplay =
     [UIImage imageWithCGImage:[originalImage CGImage]
              scale:[originalImage scale]
              orientation: UIImageOrientationUp];

因此，您正在创建一个新的 UIImage，其像素数据与原始数据相同（通过其 CGImage 属性引用），但您指定的方向不旋转数据。

【讨论】：

顺便问一下，我怎样才能真正旋转图像数据？
我猜你会用CGBitmapContextCreate（或UIGraphicsBeginImageContext简写）创建一个大小合适的CGContext，使用CGContextRotateCTM设置旋转，使用drawInRect: UIImage 或 CGContextDrawImage 带有图像的 CGImage 属性，然后将上下文转换为图像，如果您使用 UIKit 创建上下文，则使用 UIGraphicsGetImageFromCurrentImageContext（然后是 UIGraphicsEndImageContext），或者如果使用 CGBitmapContextCreateImage你坚持使用核心图形。 UIKit 不是线程安全的，但代码会更整洁。
当我将图像放入 ImageView 时，我无法让它工作......即使我正在创建具有镜像方向的图像，它也只是以原始方向显示图像：[UIImage imageWithCGImage:image.CGImage scale:image.scaleorientation:UIImageOrientationUpMirrored]...OP 询问有关使用 ImageView 但我无法让此解决方案在 ImageView 中工作...
适用于 PNG，但不适用于 HEIC。

【解决方案2】：

您可以完全避免手动进行转换和缩放，正如 an0 在此答案 here 中所建议的那样：

- (UIImage *)normalizedImage {
    if (self.imageOrientation == UIImageOrientationUp) return self; 

    UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
    [self drawInRect:(CGRect){0, 0, self.size}];
    UIImage *normalizedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return normalizedImage;
}

UIImage 方法size 和drawInRect 的文档明确声明它们考虑了方向。

【讨论】：

这是救命稻草。
我在哪里粘贴这个？

【解决方案3】：

斯威夫特 3.1

func fixImageOrientation(_ image: UIImage)->UIImage {
    UIGraphicsBeginImageContext(image.size)
    image.draw(at: .zero)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return newImage ?? image
}

【讨论】：

这是一个完美的解决方案:)
你值得拥有我的朋友
这比that 好。这在 swift 4 中有效，但事实并非如此。
谢谢。如果您需要将图像上传到服务器，则此方法有效，而不仅仅是显示为大多数其他答案。
效果很好。拍摄任何图像并以 .up 方向保存

【解决方案4】：

此方法首先检查UIImage的当前方向，然后以顺时针方向改变方向并返回UIImage。您可以将此图像显示为

self.imageView.image = rotateImage(currentUIImage)

   func rotateImage(image:UIImage)->UIImage
    {
        var rotatedImage = UIImage();
        switch image.imageOrientation
        {
            case UIImageOrientation.Right:
            rotatedImage = UIImage(CGImage:image.CGImage!, scale: 1, orientation:UIImageOrientation.Down);

           case UIImageOrientation.Down:
            rotatedImage = UIImage(CGImage:image.CGImage!, scale: 1, orientation:UIImageOrientation.Left);

            case UIImageOrientation.Left:
            rotatedImage = UIImage(CGImage:image.CGImage!, scale: 1, orientation:UIImageOrientation.Up);

             default:
            rotatedImage = UIImage(CGImage:image.CGImage!, scale: 1, orientation:UIImageOrientation.Right);
        }
        return rotatedImage;
    }

Swift 4 版本

func rotateImage(image:UIImage) -> UIImage
    {
        var rotatedImage = UIImage()
        switch image.imageOrientation
        {
        case .right:
            rotatedImage = UIImage(cgImage: image.cgImage!, scale: 1.0, orientation: .down)

        case .down:
            rotatedImage = UIImage(cgImage: image.cgImage!, scale: 1.0, orientation: .left)

        case .left:
            rotatedImage = UIImage(cgImage: image.cgImage!, scale: 1.0, orientation: .up)

        default:
            rotatedImage = UIImage(cgImage: image.cgImage!, scale: 1.0, orientation: .right)
        }

        return rotatedImage
    }

【讨论】：

您好 Varender，感谢您对 SO 的帮助。你能谈谈你认为这可能对马丁有什么帮助吗？您的解决方案比旋转数据更优雅吗？
1.我们将从 UIImageView 获取当前 UIImage 2. 我们将调用此方法 (rotateImage) 并将此当前 UIImage 作为参数传递 3. 将返回值存储到 UIImageView.image /* 这将在图像视图中旋转数据:)： )
先生，在我看来这是最好的答案，因为如果我们将旋转整个 UIImageView 那么 UIImageView X 是一个负值。但是如果我们旋转数据，那么 UIImageView 将保持原位，只有数据会被旋转。如果你采用方形 UIImageView，那么你可以使用 CGAffineTransformMakeRotate 简单地转换整个 UIImageView。
这应该是公认的答案！像魅力一样工作:)
在 swift 3 中：rotatedImage = UIImage(cgImage:image.cgImage!, scale: 1,orientation:UIImageOrientation.right)

【解决方案5】：

我将Anomie's answer here 中的代码（上面由 suvish valsan 复制粘贴）转换为 Swift：

func fixOrientation() -> UIImage {
    if self.imageOrientation == UIImageOrientation.Up {
        return self
    }

    var transform = CGAffineTransformIdentity

    switch self.imageOrientation {
    case .Down, .DownMirrored:
        transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height)
        transform = CGAffineTransformRotate(transform, CGFloat(M_PI));

    case .Left, .LeftMirrored:
        transform = CGAffineTransformTranslate(transform, self.size.width, 0);
        transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2));

    case .Right, .RightMirrored:
        transform = CGAffineTransformTranslate(transform, 0, self.size.height);
        transform = CGAffineTransformRotate(transform, CGFloat(-M_PI_2));

    case .Up, .UpMirrored:
        break
    }

    switch self.imageOrientation {

    case .UpMirrored, .DownMirrored:
        transform = CGAffineTransformTranslate(transform, self.size.width, 0)
        transform = CGAffineTransformScale(transform, -1, 1)

    case .LeftMirrored, .RightMirrored:
        transform = CGAffineTransformTranslate(transform, self.size.height, 0)
        transform = CGAffineTransformScale(transform, -1, 1);

    default:
        break;
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    let ctx = CGBitmapContextCreate(
        nil,
        Int(self.size.width),
        Int(self.size.height),
        CGImageGetBitsPerComponent(self.CGImage),
        0,
        CGImageGetColorSpace(self.CGImage),
        UInt32(CGImageGetBitmapInfo(self.CGImage).rawValue)
    )

    CGContextConcatCTM(ctx, transform);

    switch self.imageOrientation {
    case .Left, .LeftMirrored, .Right, .RightMirrored:
        // Grr...
        CGContextDrawImage(ctx, CGRectMake(0, 0, self.size.height,self.size.width), self.CGImage);

    default:
        CGContextDrawImage(ctx, CGRectMake(0, 0, self.size.width,self.size.height), self.CGImage);
        break;
    }

    // And now we just create a new UIImage from the drawing context
    let cgimg = CGBitmapContextCreateImage(ctx)

    let img = UIImage(CGImage: cgimg!)

    return img;
}

（我用self替换了所有出现的参数image，因为我的代码是UIImage的扩展）。

编辑： Swift 3 版本。

该方法返回一个可选的，因为许多中间调用可能会失败，我不喜欢使用!。

func fixOrientation() -> UIImage? {

    guard let cgImage = self.cgImage else {
        return nil
    }

    if self.imageOrientation == UIImageOrientation.up {
        return self
    }

    let width  = self.size.width
    let height = self.size.height

    var transform = CGAffineTransform.identity

    switch self.imageOrientation {
    case .down, .downMirrored:
        transform = transform.translatedBy(x: width, y: height)
        transform = transform.rotated(by: CGFloat.pi)

    case .left, .leftMirrored:
        transform = transform.translatedBy(x: width, y: 0)
        transform = transform.rotated(by: 0.5*CGFloat.pi)

    case .right, .rightMirrored:
        transform = transform.translatedBy(x: 0, y: height)
        transform = transform.rotated(by: -0.5*CGFloat.pi)

    case .up, .upMirrored:
        break
    }

    switch self.imageOrientation {
    case .upMirrored, .downMirrored:
        transform = transform.translatedBy(x: width, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)

    case .leftMirrored, .rightMirrored:
        transform = transform.translatedBy(x: height, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)

    default:
        break;
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    guard let colorSpace = cgImage.colorSpace else {
        return nil
    }

    guard let context = CGContext(
        data: nil,
        width: Int(width),
        height: Int(height),
        bitsPerComponent: cgImage.bitsPerComponent,
        bytesPerRow: 0,
        space: colorSpace,
        bitmapInfo: UInt32(cgImage.bitmapInfo.rawValue)
        ) else {
            return nil
    }

    context.concatenate(transform);

    switch self.imageOrientation {

    case .left, .leftMirrored, .right, .rightMirrored:
        // Grr...
        context.draw(cgImage, in: CGRect(x: 0, y: 0, width: height, height: width))

    default:
        context.draw(cgImage, in: CGRect(x: 0, y: 0, width: width, height: height))
    }

    // And now we just create a new UIImage from the drawing context
    guard let newCGImg = context.makeImage() else {
        return nil
    }

    let img = UIImage(cgImage: newCGImg)

    return img;
}

（注意：Swift 3 版本的 odes 在 Xcode 8.1 下编译，但尚未测试它是否真的有效。可能某处有错字，混淆了宽度/高度等。请随时指出/修复任何错误）。

【讨论】：

我在转换为 swift 3 后使用了上面的代码。如果有人需要 swift 3 版本，请在下面查看我的答案
图像方向完全没有改变。抱歉，我是 iOS 开发新手。我所做的是，我将该函数用于 UIImage 扩展，然后以编程方式将其设置在 func viewDidLoad 中。此图片来自三星手机photos.google.com/share/…，包含 270 个 CW 方向 exif 数据。这是我如何使用它let background: UIImage? = UIImage(named: "background_image")?.fixOrientation() backgroundImage.image = background
有人使用这个@Nicolas 遇到内存泄漏问题吗？看起来 CGImages 没有被释放。我的应用程序是一个海量照片管理应用程序，可以处理许多照片。此函数似乎在每次运行时都在泄漏内存。有什么快速解决办法吗？
@MichaelReilly 嗯，还没有详细查看它，但是 CoreGraphics 调用应该可以在 swift 中与 ARC 一起使用。
@MichaelReilly 我找到了这个答案，这似乎证实了我的观察：stackoverflow.com/a/25790214/433373

【解决方案6】：

Swift 中的 UIImage 扩展。你根本不需要做所有的翻转，真的。 Objective-C original is here，但我添加了尊重原始图像 alpha 的位（粗略，但它可以区分不透明图像和透明图像）。

// from https://github.com/mbcharbonneau/UIImage-Categories/blob/master/UIImage%2BAlpha.m
// Returns true if the image has an alpha layer
    private func hasAlpha() -> Bool {
        guard let cg = self.cgImage else { return false }
        let alpha = cg.alphaInfo
        let retVal = (alpha == .first || alpha == .last || alpha == .premultipliedFirst || alpha == .premultipliedLast)
        return retVal
    }

    func normalizedImage() -> UIImage? {
        if self.imageOrientation == .up {
            return self
        }
        UIGraphicsBeginImageContextWithOptions(self.size, !self.hasAlpha(), self.scale)
        var rect = CGRect.zero
        rect.size = self.size
        self.draw(in: rect)
        let retVal = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return retVal
    }

【讨论】：

【解决方案7】：

考虑到图像方向，这是一个可行的示例代码：

#define rad(angle) ((angle) / 180.0 * M_PI)
- (CGAffineTransform)orientationTransformedRectOfImage:(UIImage *)img
{
    CGAffineTransform rectTransform;
    switch (img.imageOrientation)
    {
        case UIImageOrientationLeft:
            rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(90)), 0, -img.size.height);
            break;
        case UIImageOrientationRight:
            rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(-90)), -img.size.width, 0);
            break;
        case UIImageOrientationDown:
            rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(-180)), -img.size.width, -img.size.height);
            break;
        default:
            rectTransform = CGAffineTransformIdentity;
    };

    return CGAffineTransformScale(rectTransform, img.scale, img.scale);
}


- (UIImage *)croppedImage:(UIImage*)orignialImage InRect:(CGRect)visibleRect{
    //transform visible rect to image orientation
    CGAffineTransform rectTransform = [self orientationTransformedRectOfImage:orignialImage];
    visibleRect = CGRectApplyAffineTransform(visibleRect, rectTransform);

    //crop image
    CGImageRef imageRef = CGImageCreateWithImageInRect([orignialImage CGImage], visibleRect);
    UIImage *result = [UIImage imageWithCGImage:imageRef scale:orignialImage.scale orientation:orignialImage.imageOrientation];
    CGImageRelease(imageRef);
    return result;
}

【讨论】：

【解决方案8】：

我将代码从@Nicolas Miari 的答案转换为 Swift 3，以防万一有人需要

func fixOrientation() -> UIImage
{

    if self.imageOrientation == UIImageOrientation.up {
        return self
    }

    var transform = CGAffineTransform.identity

    switch self.imageOrientation {
    case .down, .downMirrored:
        transform = transform.translatedBy(x: self.size.width, y: self.size.height)
        transform = transform.rotated(by: CGFloat(M_PI));

    case .left, .leftMirrored:
        transform = transform.translatedBy(x: self.size.width, y: 0);
        transform = transform.rotated(by: CGFloat(M_PI_2));

    case .right, .rightMirrored:
        transform = transform.translatedBy(x: 0, y: self.size.height);
        transform = transform.rotated(by: CGFloat(-M_PI_2));

    case .up, .upMirrored:
        break
    }


    switch self.imageOrientation {

    case .upMirrored, .downMirrored:
        transform = transform.translatedBy(x: self.size.width, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)

    case .leftMirrored, .rightMirrored:
        transform = transform.translatedBy(x: self.size.height, y: 0)
        transform = transform.scaledBy(x: -1, y: 1);

    default:
        break;
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    let ctx = CGContext(
        data: nil,
        width: Int(self.size.width),
        height: Int(self.size.height),
        bitsPerComponent: self.cgImage!.bitsPerComponent,
        bytesPerRow: 0,
        space: self.cgImage!.colorSpace!,
        bitmapInfo: UInt32(self.cgImage!.bitmapInfo.rawValue)
    )



    ctx!.concatenate(transform);

    switch self.imageOrientation {

    case .left, .leftMirrored, .right, .rightMirrored:
        // Grr...
        ctx?.draw(self.cgImage!, in: CGRect(x:0 ,y: 0 ,width: self.size.height ,height:self.size.width))

    default:
        ctx?.draw(self.cgImage!, in: CGRect(x:0 ,y: 0 ,width: self.size.width ,height:self.size.height))
        break;
    }

    // And now we just create a new UIImage from the drawing context
    let cgimg = ctx!.makeImage()

    let img = UIImage(cgImage: cgimg!)

    return img;

}

【讨论】：

在委托方法imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any] let imageCaptured:UIImage = info[UIImagePickerControllerOriginalImage] as! UIImage捕获图像后，图像始终是正确的方向，此方法返回图像:(
是的，图像方向始终是正确的，但它在 UIImageView 上正确显示。 Apple 有一些内部数据用于正确显示

【解决方案9】：

如果您需要旋转并修复扩展下方的图像方向会很有用。

extension UIImage {

    public func imageRotatedByDegrees(degrees: CGFloat) -> UIImage {
        //Calculate the size of the rotated view's containing box for our drawing space
        let rotatedViewBox: UIView = UIView(frame: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
        let t: CGAffineTransform = CGAffineTransform(rotationAngle: degrees * CGFloat.pi / 180)
        rotatedViewBox.transform = t
        let rotatedSize: CGSize = rotatedViewBox.frame.size
        //Create the bitmap context
        UIGraphicsBeginImageContext(rotatedSize)
        let bitmap: CGContext = UIGraphicsGetCurrentContext()!
        //Move the origin to the middle of the image so we will rotate and scale around the center.
        bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2)
        //Rotate the image context
        bitmap.rotate(by: (degrees * CGFloat.pi / 180))
        //Now, draw the rotated/scaled image into the context
        bitmap.scaleBy(x: 1.0, y: -1.0)
        bitmap.draw(self.cgImage!, in: CGRect(x: -self.size.width / 2, y: -self.size.height / 2, width: self.size.width, height: self.size.height))
        let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
        return newImage
    }


    public func fixedOrientation() -> UIImage {
        if imageOrientation == UIImageOrientation.up {
            return self
        }

        var transform: CGAffineTransform = CGAffineTransform.identity

        switch imageOrientation {
        case UIImageOrientation.down, UIImageOrientation.downMirrored:
            transform = transform.translatedBy(x: size.width, y: size.height)
            transform = transform.rotated(by: CGFloat.pi)
            break
        case UIImageOrientation.left, UIImageOrientation.leftMirrored:
            transform = transform.translatedBy(x: size.width, y: 0)
            transform = transform.rotated(by: CGFloat.pi/2)
            break
        case UIImageOrientation.right, UIImageOrientation.rightMirrored:
            transform = transform.translatedBy(x: 0, y: size.height)
            transform = transform.rotated(by: -CGFloat.pi/2)
            break
        case UIImageOrientation.up, UIImageOrientation.upMirrored:
            break
        }

        switch imageOrientation {
        case UIImageOrientation.upMirrored, UIImageOrientation.downMirrored:
            transform.translatedBy(x: size.width, y: 0)
            transform.scaledBy(x: -1, y: 1)
            break
        case UIImageOrientation.leftMirrored, UIImageOrientation.rightMirrored:
            transform.translatedBy(x: size.height, y: 0)
            transform.scaledBy(x: -1, y: 1)
        case UIImageOrientation.up, UIImageOrientation.down, UIImageOrientation.left, UIImageOrientation.right:
            break
        }

        let ctx: CGContext = CGContext(data: nil,
                                       width: Int(size.width),
                                       height: Int(size.height),
                                       bitsPerComponent: self.cgImage!.bitsPerComponent,
                                       bytesPerRow: 0,
                                       space: self.cgImage!.colorSpace!,
                                       bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue)!

        ctx.concatenate(transform)

        switch imageOrientation {
        case UIImageOrientation.left, UIImageOrientation.leftMirrored, UIImageOrientation.right, UIImageOrientation.rightMirrored:
            ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
        default:
            ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
            break
        }

        let cgImage: CGImage = ctx.makeImage()!

        return UIImage(cgImage: cgImage)
    }
}

【讨论】：

【解决方案10】：

感谢 Waseem05 的 Swift 3 翻译，但他的方法仅在我将其包装在 UIImage 的扩展中并将其放置在父类之外/下方时才对我有用，如下所示：

extension UIImage {

        func fixOrientation() -> UIImage
        {

            if self.imageOrientation == UIImageOrientation.up {
            return self
        }

        var transform = CGAffineTransform.identity

        switch self.imageOrientation {
        case .down, .downMirrored:
            transform = transform.translatedBy(x: self.size.width, y: self.size.height)
            transform = transform.rotated(by: CGFloat(M_PI));

        case .left, .leftMirrored:
            transform = transform.translatedBy(x: self.size.width, y: 0);
            transform = transform.rotated(by: CGFloat(M_PI_2));

        case .right, .rightMirrored:
            transform = transform.translatedBy(x: 0, y: self.size.height);
            transform = transform.rotated(by: CGFloat(-M_PI_2));

        case .up, .upMirrored:
            break
        }


        switch self.imageOrientation {

        case .upMirrored, .downMirrored:
            transform = transform.translatedBy(x: self.size.width, y: 0)
            transform = transform.scaledBy(x: -1, y: 1)

        case .leftMirrored, .rightMirrored:
            transform = transform.translatedBy(x: self.size.height, y: 0)
            transform = transform.scaledBy(x: -1, y: 1);

        default:
            break;
        }

        // Now we draw the underlying CGImage into a new context, applying the transform
        // calculated above.
        let ctx = CGContext(
            data: nil,
            width: Int(self.size.width),
            height: Int(self.size.height),
            bitsPerComponent: self.cgImage!.bitsPerComponent,
            bytesPerRow: 0,
            space: self.cgImage!.colorSpace!,
            bitmapInfo: UInt32(self.cgImage!.bitmapInfo.rawValue)
        )



        ctx!.concatenate(transform);

        switch self.imageOrientation {

        case .left, .leftMirrored, .right, .rightMirrored:
            // Grr...
            ctx?.draw(self.cgImage!, in: CGRect(x:0 ,y: 0 ,width: self.size.height ,height:self.size.width))

        default:
            ctx?.draw(self.cgImage!, in: CGRect(x:0 ,y: 0 ,width: self.size.width ,height:self.size.height))
            break;
        }

        // And now we just create a new UIImage from the drawing context
        let cgimg = ctx!.makeImage()

        let img = UIImage(cgImage: cgimg!)

        return img;

    }
}

然后调用它：

let correctedImage:UIImage = wonkyImage.fixOrientation()

然后一切都很好！当我们不需要前置/后置摄像头和上/下/左/右设备方向元数据时，Apple 应该更容易丢弃方向。

【讨论】：

【解决方案11】：

extension UIImage {
    func fixImageOrientation() -> UIImage {
        UIGraphicsBeginImageContext(self.size)
        self.draw(at: .zero)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage ?? self
    }
}

像上面的例子一样创建扩展。
致电：imageView.image?.fixImageOrientation() 或 UIImage(named: "someImage").fixImageOrientation()
祝大家好运！

【讨论】：

这很好用。但是内存会像任何东西一样堆积起来，如果在循环中调用它，应用程序就会崩溃。
@abhimuralidharan，我没有在循环中检查它，但 100% 存在一种应用方式。

【解决方案12】：

Swift 3.0 版汤米的回答

let imageToDisplay = UIImage.init(cgImage: originalImage.cgImage!, scale: originalImage.scale, orientation: UIImageOrientation.up)

【讨论】：

【解决方案13】：

灵感来自@Aqua Answer.....

在目标 C 中

- (UIImage *)fixImageOrientation:(UIImage *)img {

   UIGraphicsBeginImageContext(img.size);
   [img drawAtPoint:CGPointZero];

   UIImage *newImg = UIGraphicsGetImageFromCurrentImageContext();
   UIGraphicsEndImageContext();

   if (newImg) {
       return newImg;
   }

   return img;
}

【讨论】：

【解决方案14】：

我尝试了选中标记的解决方案，但它对我不起作用。但以下解决方案适用于在转换为 png 之前从相机固定方向。

斯威夫特 5：

let imageToDisplay = originalImage.resize(new: originalImage.resize)

【讨论】：

尝试用更具描述性的评论来回答问题，并用合适的答案回答问题
@JhonnyTawk 感谢您的建议，我编辑了答案