使用 imagePicker 时 ImageView 旋转答案

【问题标题】：ImageView rotating when using imagePicker使用 imagePicker 时 ImageView 旋转
【发布时间】：2016-07-01 07:46:37
【问题描述】：

我有一个表格视图，在单元格中，有一个图像和 2 个标签。我正在使用imagePicker 从我的相机胶卷中选择一张照片并将该照片放入单元格图像中。但是，当照片是纵向模式照片时，图像会旋转 90 度。

在下面的代码中，posting 是一个连接到表格视图单元格中的imageview 的插座，我初始化了一个UIImagePickerController。

class MakePostVC: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

@IBOutlet weak var postImg: UIImageView!
@IBOutlet weak var postTitle: UITextField!
@IBOutlet weak var postDescrip: UITextField!

var imgPicker: UIImagePickerController!

override func viewDidLoad() {
    super.viewDidLoad()

    postImg.layer.cornerRadius = 30
    postImg.clipsToBounds = true

    imgPicker = UIImagePickerController()
    imgPicker.delegate = self

}

这是didFinishPickingImage的函数：

func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage, editingInfo: [String : AnyObject]?) {
    imgPicker.dismissViewControllerAnimated(true, completion: nil)
    postImg.image = image
}

我在 SO 上查看过类似的帖子，但解决方案似乎不起作用。
有什么建议吗？

谢谢

【问题讨论】：

标签： ios swift iphone xcode uikit

【解决方案1】：

更新到 Swift 5.3、iOS 14

Sunil Sharma 的solution 为我工作。这是 Swift 5

的翻译版本

extension UIImage {
    var fixedOrientation: UIImage {
        guard imageOrientation != .up else { return self }
        
        var transform: CGAffineTransform = .identity
        switch imageOrientation {
        case .down, .downMirrored:
            transform = transform
                .translatedBy(x: size.width, y: size.height).rotated(by: .pi)
        case .left, .leftMirrored:
            transform = transform
                .translatedBy(x: size.width, y: 0).rotated(by: .pi)
        case .right, .rightMirrored:
            transform = transform
                .translatedBy(x: 0, y: size.height).rotated(by: -.pi/2)
        case .upMirrored:
            transform = transform
                .translatedBy(x: size.width, y: 0).scaledBy(x: -1, y: 1)
        default:
            break
        }
        
        guard
            let cgImage = cgImage,
            let colorSpace = cgImage.colorSpace,
            let context = CGContext(
                data: nil, width: Int(size.width), height: Int(size.height),
                bitsPerComponent: cgImage.bitsPerComponent, bytesPerRow: 0,
                space: colorSpace, bitmapInfo: cgImage.bitmapInfo.rawValue
            )
        else { return self }
        context.concatenate(transform)
        
        var rect: CGRect
        switch imageOrientation {
        case .left, .leftMirrored, .right, .rightMirrored:
            rect = CGRect(x: 0, y: 0, width: size.height, height: size.width)
        default:
            rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        }
        
        context.draw(cgImage, in: rect)
        return context.makeImage().map { UIImage(cgImage: $0) } ?? self
    }
}

【讨论】：

您问自己的那些实例之一？为什么这是必要的... Anway，只需将复制粘贴到我的 swiftui 项目中并像魅力一样工作。谢谢

【解决方案2】：

UIImage 包含一个名为 imageOrientation 的属性。正如 Apple 文档中描述的该属性：

图像方向会影响图像数据的显示方式画。默认情况下，图像以“向上”方向显示。如果图像具有关联的元数据（例如 EXIF 信息），但是，此属性包含该元数据指示的方向。

所以这个属性用来反映相机相对于地面的位置。所以当你从手机相机拍摄图像时，它会将方向标志保存在UIImageimageOrientation属性中。
在显示时，如果忽略此属性，则您可能找不到正确方向的图像。仅供参考，请参阅下面的图像，相机如何拍摄图像，然后编码和显示。请查看此link 了解更多详细信息。

在 ios 中解决这个问题
Objective-C

制作类别

UIImage+fixOrientation.h

@interface UIImage (fixOrientation)

- (UIImage *)fixOrientation;

@end

UIImage+fixOrientation.m

@implementation UIImage (fixOrientation)

- (UIImage *)fixOrientation {

    // No-op if the orientation is already correct
    if (self.imageOrientation == UIImageOrientationUp) return self;

    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;

    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;

        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationUpMirrored:
            break;
    }

    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;

        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationDown:
        case UIImageOrientationLeft:
        case UIImageOrientationRight:
            break;
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;

        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
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

@end

斯威夫特

将扩展设为

extension UIImage {

    func fixOrientation() -> UIImage {

        // No-op if the orientation is already correct
        if ( self.imageOrientation == UIImageOrientation.Up ) {
            return self;
        }

        // We need to calculate the proper transformation to make the image upright.
        // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
        var transform: CGAffineTransform = CGAffineTransformIdentity

        if ( self.imageOrientation == UIImageOrientation.Down || self.imageOrientation == UIImageOrientation.DownMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI))
        }

        if ( self.imageOrientation == UIImageOrientation.Left || self.imageOrientation == UIImageOrientation.LeftMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.width, 0)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2))
        }

        if ( self.imageOrientation == UIImageOrientation.Right || self.imageOrientation == UIImageOrientation.RightMirrored ) {
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform,  CGFloat(-M_PI_2));
        }

        if ( self.imageOrientation == UIImageOrientation.UpMirrored || self.imageOrientation == UIImageOrientation.DownMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.width, 0)
            transform = CGAffineTransformScale(transform, -1, 1)
        }

        if ( self.imageOrientation == UIImageOrientation.LeftMirrored || self.imageOrientation == UIImageOrientation.RightMirrored ) {
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
        }

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

        CGContextConcatCTM(ctx, transform)

        if ( self.imageOrientation == UIImageOrientation.Left ||
            self.imageOrientation == UIImageOrientation.LeftMirrored ||
            self.imageOrientation == UIImageOrientation.Right ||
            self.imageOrientation == UIImageOrientation.RightMirrored ) {
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage)
        } else {
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage)
        }

        // And now we just create a new UIImage from the drawing context and return it
        return UIImage(CGImage: CGBitmapContextCreateImage(ctx)!)
    }
}

【讨论】：

【解决方案3】：

您可以像这篇文章一样旋转图像： https://stackoverflow.com/a/1317194/3928412

你还需要获取设备旋转，你可以像这样得到它：

 UIDevice.currentDevice().orientation

【讨论】：