Image decoding/decompression still happening on the main thread about ios-twitter-image-pipeline HOT 5 CLOSED

Hello. I took a quick look at this from the Twitter app and did not see any stack frames with the term "jpeg" or "decode" in them. I've intentionally run this without symbols. Can you provide an Instruments trace or some screenshots with what you are seeing?

from ios-twitter-image-pipeline.

Hmm, yeah I can definitely get that. I'll do it tomorrow. One thing is these UIImages are being served to SwiftUI.Images. Maybe SwiftUI is missing an optimization. I can double check if that is the issue too.

from ios-twitter-image-pipeline.

from ios-twitter-image-pipeline.

It looks like a tick of a CADisplayLink timer is creating a Core Animation transaction that's kicking this off. I've not used SwiftUI, but in UIKit terms, I suspect the frame the view is being set to a size that does not match the underlying image that has been downloaded (and a contentMode of "fit").

Maybe you can set a breakpoint in setFrame on the view and see where it's being set?

from ios-twitter-image-pipeline.

Hmm, there is no real setFrame equivalent, but I just tried replacing Image(uiImage: image) with _UIImageView(image: image). and there is no decoding on the main thread, so seems like a bug in SwiftUI.Image.

private struct _UIImageView: UIViewRepresentable {
    private let image: UIImage

    init(image: UIImage) {
        self.image = image
    }

    func makeUIView(context: Context) -> UIImageView {
        return UIImageView()
    }

    func updateUIView(_ uiView: UIImageView, context: Context) {
        uiView.image = image
    }

    typealias UIViewType = UIImageView

}

from ios-twitter-image-pipeline.