Question

我让用户从相机胶卷中选择要裁剪的照片。我以缩略图的形式显示所有这些图片供用户按下。

我使用UIImage(CGImage: asset.fullScreenImage!.CGImage!, scale: scale, orientation: UIImageOrientation.Up)确保我的图片与缩略图中的图片保持一致。使用asset.fullResolutionImage!，这不起作用。

现在出现了奇怪的部分。当我用iPhone相机拍照时，然后前往我的裁剪ViewController，图像旋转90度！我不明白为什么。

如果我离开我的应用程序，请正常使用相机拍照，将其保存到相机胶卷，然后从缩略图列表中选择它，就像我做其他照片一样，效果非常好。

这是什么原因？如何修复它？

编辑：下面发布了两个解决方案。一个在Objective-C中，另一个是在Swift中的翻译副本。

Answer 1

您可以尝试使用此类别：

UIImage+FixOrientation.h

UIImage+FixOrientation.m

它是在Objective-C中构建的，然后您可以使用bridging header将 ObjC 与 Swift 结合使用，或者您可以查看了解如何解决这个问题。

用法示例：

UIImage *image = <image from camera image>
image = [image fixOrientation];

Answer 2

这个答案是为了补充gontovnik的答案。

我已经采用了他的Objective-C解决方案并将其编写在Swift中。在任何需要的地方放置此功能。只需传递有问题的UIImage。

那就是说，你可能只是让它成为一个UIImage类函数。实际上只需拨打UIImage.fixOrientation(image: imageInQuestion)即可。

func fixOrientation(image: UIImage) -> UIImage {
    // No-op if the orientation is already correct
    if (image.imageOrientation == UIImageOrientation.Up) { return image; }

    println(image.imageOrientation)

    // 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 = CGAffineTransformIdentity

    switch (image.imageOrientation) {
        case .Down, .DownMirrored:
            transform = CGAffineTransformTranslate(transform, image.size.width, image.size.height)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI))
            break
        case .Left, .LeftMirrored:
            transform = CGAffineTransformTranslate(transform, image.size.width, 0)
            transform = CGAffineTransformRotate(transform, CGFloat(M_PI_2))
            break        
        case .Right, .RightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, image.size.height)
            transform = CGAffineTransformRotate(transform, CGFloat(-M_PI_2))
            break            
        case .Up, .UpMirrored:
                break
    }

    switch (image.imageOrientation) {
        case .UpMirrored, .DownMirrored:
            transform = CGAffineTransformTranslate(transform, image.size.width, 0)
            transform = CGAffineTransformScale(transform, -1, 1)
            break       
        case .LeftMirrored, .RightMirrored:
            transform = CGAffineTransformTranslate(transform, image.size.height, 0)
            transform = CGAffineTransformScale(transform, -1, 1)
            break
        case .Up, .Down, .Left, .Right:
            break
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.

    var ctx = CGBitmapContextCreate(nil, Int(image.size.width), Int(image.size.height), CGImageGetBitsPerComponent(image.CGImage), 0, CGImageGetColorSpace(image.CGImage), CGImageGetBitmapInfo(image.CGImage))

    CGContextConcatCTM(ctx, transform);

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

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

    // And now we just create a new UIImage from the drawing context
        var cgimg = CGBitmapContextCreateImage(ctx)
        var img = UIImage(CGImage: cgimg)

        return img!
}

Answer 3

Swift 3版本

"Session","QueryString","Application","cookie","Server.Transfer"

用相机拍照可以将asset.fullScreenImage旋转90度？

3 个答案: