Question

我有一个我正在处理的应用程序，它具有允许用户拍照或从照片库中选择图像的功能。代码有效，但图像始终显示大于UIImageView框。该框在故事板中设置为“缩放纵横比”，但摄像机图像拒绝符合。

以下是代码：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        if let chosenImage = info[UIImagePickerControllerOriginalImage] as? UIImage{

            imageField.image = chosenImage
        } else{
            //error message goes here
        }
        self.dismiss(animated: true, completion: nil)
    }

如何让chosenImage符合方框或方位？

Answer 1

请尝试这种方式：

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        if let chosenImage = info[UIImagePickerControllerOriginalImage] as? UIImage{

            imageField.image = chosenImage
            imageField.contentMode = UIViewContentMode.scaleToFill
            imageField.clipsToBounds = true
        } else{
            //error message goes here
        }
        self.dismiss(animated: true, completion: nil)
    }

为什么ScaleAspectFill和clipsToBounds = true会看到这个问题Why scale to fill give bigger image than UIImageVIew size? (using swift)

如果您想要更多学习，请查看此How to scale a UIImageView proportionally?

Answer 2

以下代码将调整与swift 4.0兼容的相机拍摄图像的大小。

它使用UIImageOrientaiton检查图像的EXIF属性，并根据方向值进行调整，对图像进行变换和缩放，以便获得与相机视图方向相同的返回图像。

func scaleAndRotateImage(image: UIImage, MaxResolution iIntMaxResolution: Int) -> UIImage {
        let kMaxResolution = iIntMaxResolution
        let imgRef = image.cgImage!
        let width: CGFloat = CGFloat(imgRef.width)
        let height: CGFloat = CGFloat(imgRef.height)
        var transform = CGAffineTransform.identity
        var bounds = CGRect.init(x: 0, y: 0, width: width, height: height)

        if Int(width) > kMaxResolution || Int(height) > kMaxResolution {
            let ratio: CGFloat = width / height
            if ratio > 1 {
                bounds.size.width = CGFloat(kMaxResolution)
                bounds.size.height = bounds.size.width / ratio
            }
            else {
                bounds.size.height = CGFloat(kMaxResolution)
                bounds.size.width = bounds.size.height * ratio
            }
        }
        let scaleRatio: CGFloat = bounds.size.width / width
        let imageSize = CGSize.init(width: CGFloat(imgRef.width), height: CGFloat(imgRef.height))

        var boundHeight: CGFloat
        let orient = image.imageOrientation
        // The output below is limited by 1 KB.
        // Please Sign Up (Free!) to remove this limitation.

        switch orient {
        case .up:
            //EXIF = 1
            transform = CGAffineTransform.identity
        case .upMirrored:
            //EXIF = 2
            transform = CGAffineTransform.init(translationX: imageSize.width, y: 0.0)
            transform = transform.scaledBy(x: -1.0, y: 1.0)

        case .down:
            //EXIF = 3
            transform = CGAffineTransform.init(translationX: imageSize.width, y: imageSize.height)
            transform = transform.rotated(by: CGFloat(Double.pi / 2))

        case .downMirrored:
            //EXIF = 4
            transform = CGAffineTransform.init(translationX: 0.0, y: imageSize.height)
            transform = transform.scaledBy(x: 1.0, y: -1.0)
        case .leftMirrored:
            //EXIF = 5
            boundHeight = bounds.size.height
            bounds.size.height = bounds.size.width
            bounds.size.width = boundHeight
            transform = CGAffineTransform.init(translationX: imageSize.height, y: imageSize.width)

            transform = transform.scaledBy(x: -1.0, y: 1.0)
            transform = transform.rotated(by: CGFloat(Double.pi / 2) / 2.0)
            break

        default: print("Error in processing image")
        }

        UIGraphicsBeginImageContext(bounds.size)
        let context = UIGraphicsGetCurrentContext()
        if orient == .right || orient == .left {
            context?.scaleBy(x: -scaleRatio, y: scaleRatio)
            context?.translateBy(x: -height, y: 0)
        }
        else {
            context?.scaleBy(x: scaleRatio, y: -scaleRatio)
            context?.translateBy(x: 0, y: -height)
        }
        context?.concatenate(transform)
        context?.draw(imgRef, in: CGRect.init(x: 0, y: 0, width: width, height: height))
        let imageCopy = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return imageCopy!
    }

相机图像调整大小

2 个答案: