调整sdwebImage swift大小

Question

你好，我正在使用sdwebImage在我的应用程序上显示图像。我在这里有一个代码来调整图像的大小

func resizeImage(image: UIImage, newWidth: CGFloat) -> UIImage {

    let scale = newWidth / image.size.width
    let newHeight = image.size.height * scale
    UIGraphicsBeginImageContext(CGSizeMake(newWidth, newHeight))
    image.drawInRect(CGRectMake(0, 0, newWidth, newHeight))
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return newImage
}

问题是上面的函数接受URL作为参数，而sdwebimage接受UIImage。如何在sdwebimage中调用上面的resize函数。或者简而言之，我如何调整通过sdwebImage在此处显示的图像的大小

   cell.profileImageView.sd_setImageWithURL(UIImage().absoluteURL(profileImageUrl as! String), placeholderImage: UIImage.init(named: "default-profile-icon")?.circle!, completed: completionBlock)

Answer 1

喜欢吗？

cell.profileImageView.sd_setImageWithURL(
    NSURL(string: profileImageUrl as! String),
    placeholderImage: UIImage.init(named: "default-profile-icon"),
    options: nil,
    progress: nil,
    completed: { (image: UIImage?, error: NSError?, cacheType: SDImageCacheType!, imageURL: NSURL?) in

        guard let image = image else { return }
        print("Image arrived!")
        cell.profileImageView.image = resizeImage(image, newWidth: 200)
    }
)

Answer 2

SDWebImage通过其SDWebImageManagerDelegate协议直接支持图像处理。您可以使用imageManager:transformDownloadedImage:withURL:方法对下载的图片进行转换。

您可以像这样设置镜像管理器代理：

SDWebImageManager.sharedManager.delegate = self;

Answer 3

使用共享SDWebImageManager不是一个好主意。一些进程可以在这段时间内下载图像。

我在类中使用自定义SDWebImageManager和自定义SDWebImageManagerDelegate大小调整的swift 3示例。

import SDWebImage

class ImageResizer: NSObject, SDWebImageManagerDelegate {
    private func resizeImage(_ image: UIImage, newHeight: CGFloat) -> UIImage {
        let scale = newHeight / image.size.height
        let newWidth = image.size.width * scale

        UIGraphicsBeginImageContextWithOptions(CGSize(width: newWidth, height: newHeight), false, 0)
        image.draw(in: CGRect(x: 0, y: 0, width: newWidth, height: newHeight))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return newImage!
    }

    public func imageManager(_ imageManager: SDWebImageManager, transformDownloadedImage image: UIImage?, with imageURL: URL?) -> UIImage? {
        guard let _image = image else {
            return nil
        }

        return resizeImage(_image, newHeight: 20)
    }
}


class BasicTrainView: XibView {
    static let imageManager: SDWebImageManager = SDWebImageManager()
    static let imageResizer = ImageResizer()

    func xxx() {
        BasicTrainView.imageManager.delegate = BasicTrainView.imageResizer
        BasicTrainView.imageManager.loadImage(with: logoURL, options: [], progress: nil) { (image, _, error, sdImageCacheType, _, url) -> Void in
            guard let _image = image else {
                self.carrierLogoImageView.image = nil
                return
            }

            self.carrierLogoImageView.image = _image
        }
    }
}