在上传到Google Cloud存储之前调整图像大小并进行压缩

Question

我已经做了一个功能，在保持纵横比的同时将图像调整到最大宽度和高度。另外我正在基于compressionQuality压缩图像 - 我用3024x4032的jpeg图像@ 11.7 mb测试了这个。

maxWidth = 800px
maxHeight = 1200px
compressionQuality = 0.5

该功能确实将图像尺寸从11.7mb减小到0.51mb，但宽度和高度没有正确减小。上传到Firebase后，图像尺寸是1600 x 2134px的两倍...但它应该是800x1066px（一半）

你能看出什么问题吗？

import UIKit
import Foundation

class ImageEdit {
        static let instance = ImageEdit()

    func resizeAndCompressImageWith(image: UIImage, maxWidth: CGFloat, maxHeight: CGFloat, compressionQuality: CGFloat) -> Data? {

    let horizontalRatio = maxWidth / image.size.width
    let verticalRatio = maxHeight / image.size.height


    let ratio = min(horizontalRatio, verticalRatio)

    let newSize = CGSize(width: image.size.width * ratio, height: image.size.height * ratio)
    var newImage: UIImage

    if #available(ios 10.0, *) {
        let renderFormat = UIGraphicsImageRendererFormat.default()
        renderFormat.opaque = false
        let renderer = UIGraphicsImageRenderer(size: CGSize(width: newSize.width, height: newSize.height), format: renderFormat)
        newImage = renderer.image {
            (context) in
            image.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
        }
    } else {
        UIGraphicsBeginImageContextWithOptions(CGSize(width: newSize.width, height: newSize.height), true, 0)
        image.draw(in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
        newImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()
    }

            let data = UIImageJPEGRepresentation(newImage, compressionQuality)



    return data

}

}

这是将图像上传到firebase的代码。

func uploadImageToFirebaseAndReturnImageURL(directory: String, image: UIImage!, maxWidth: CGFloat, maxHeight: CGFloat, compressionQuality: CGFloat, handler: @escaping(_ imageURL: String)  -> ()) {
        let imageName = NSUUID().uuidString // create unique image name

        if let uploadData = ImageEdit.instance.resizeAndCompressImageWith(image: image, maxWidth: maxWidth, maxHeight: maxHeight, compressionQuality: compressionQuality) {

            DB_STORE.child(directory).child(imageName).putData(uploadData, metadata: nil, completion: { (metadata, error) in

                if error != nil {
                    print(error ?? "Image upload failed for unknown reason")
                    return
                }

                // if URL exist, then return imageURL
                if let imageURL = metadata?.downloadURL()?.absoluteString {
                  handler (imageURL)


                }
                return

            })
        }



    }

Answer 1

另一答案