SDWebImage process images before caching

Question

I fetch a lot of images from the web, and they are all kind of sizes - they can be big, small etc..

So I can resize them when I display them in the cell but this is

Answer 1

I had the same problem as you, and tried tweaking SDWebImage first, but ended up building my own component that solved the problem. You can take take a look at it here : https://github.com/adig/RemoteImageView

Answer 2

SDWebImage 3.8.2

If using UIImageView category sd_setImageWithURL. I have created another UIImageView category (extension)

func modifiedImageFromUrl(url: NSURL?) {
    self.sd_setImageWithURL(url) { (image, error, cacheType, url) in
        if cacheType == SDImageCacheType.None && image != nil {
            dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0)) {
                let modifiedImage = // modify image as you want

                dispatch_async(dispatch_get_main_queue()) {
                    SDWebImageManager.sharedManager().saveImageToCache(modifiedImage, forURL: url)

                    self.image = modifiedImage
                }
            }
        }
    }
}

Answer 3

Expansion on MaeSTRo's answer in Swift 3:

myImageView.sd_setImage(with: imageUrl){ (image, error, cacheType, url) in
    guard let image = image, cacheType == .none else { return }

    DispatchQueue.global(qos: .userInitiated).async {
        let modifiedImage = myImageProcessor(image)
        SDWebImageManager.shared().saveImage(toCache: modifiedImage, for: imageUrl)
        DispatchQueue.main.async {
            myImageView.image = modifiedImage
            myImageView.setNeedsDisplay()
        }
    }
}

Answer 4

SDWebImage developer Olivier Poitrey answered this question for me here.

You have to implement the SDWebImageManagerDelegate protocol and then set it as the shared manager's delegate like this:

SDWebImageManager.sharedManager.delegate = self;

using the imageManager:transformDownloadedImage:withURL: instance method.

More information.

Worked perfectly for me.