Question

在我的应用中，用户从照片库中选择一张图片，然后转到收集单元格中的一个单元格。单元格仅包含ImageView。显示图像时，如果是前置摄像头拍摄的图像，如果是肖像则向右旋转90度，如果是横向则旋转180度。

我试过这个扩展，但它没有用。还尝试将图像内容模式更改为：方面填充，宽高比适合，缩放以填充。但没什么。

func fixedOrientation() -> UIImage? {

    guard imageOrientation != UIImageOrientation.up else {
        //This is default orientation, don't need to do anything
        return self.copy() as? UIImage
    }

    guard let cgImage = self.cgImage else {
        //CGImage is not available
        return nil
    }

    guard let colorSpace = cgImage.colorSpace, let ctx = CGContext(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: cgImage.bitsPerComponent, bytesPerRow: 0, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
        return nil //Not able to create CGContext
    }

    var transform: CGAffineTransform = CGAffineTransform.identity

    switch imageOrientation {
    case .down, .downMirrored:
        transform = transform.translatedBy(x: size.width, y: size.height)
        transform = transform.rotated(by: CGFloat.pi)
        break
    case .left, .leftMirrored:
        transform = transform.translatedBy(x: size.width, y: 0)
        transform = transform.rotated(by: CGFloat.pi / 2.0)
        break
    case .right, .rightMirrored:
        transform = transform.translatedBy(x: 0, y: size.height)
        transform = transform.rotated(by: CGFloat.pi / -2.0)
        break
    case .up, .upMirrored:
        break
    }

    //Flip image one more time if needed to, this is to prevent flipped image
    switch imageOrientation {
    case .upMirrored, .downMirrored:
        transform.translatedBy(x: size.width, y: 0)
        transform.scaledBy(x: -1, y: 1)
        break
    case .leftMirrored, .rightMirrored:
        transform.translatedBy(x: size.height, y: 0)
        transform.scaledBy(x: -1, y: 1)
    case .up, .down, .left, .right:
        break
    }

    ctx.concatenate(transform)

    switch imageOrientation {
    case .left, .leftMirrored, .right, .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
    }

    guard let newCGImage = ctx.makeImage() else { return nil }
    return UIImage.init(cgImage: newCGImage, scale: 1, orientation: .up)
}

UIImageView - 前置摄像头图像旋转

0 个答案: