mapbox / mapbox/MapboxStatic.swift

[CFNetwork] Synchronous URL loading of https://api.mapbox.com/styles/v1/mapbox..... should not occur on this application's main thread as it may lead to UI unresponsiveness. Please switch to an asynchronous networking API such as URLSession.

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Dominant language
Swift
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Description

Xcode show the warning when I tried to access to Snapshot#image:
[CFNetwork] Synchronous URL loading of https://api.mapbox.com/styles/v1/mapbox..... should not occur on this application's main thread as it may lead to UI unresponsiveness. Please switch to an asynchronous networking API such as URLSession.
The class emitted this warning is Snapshot
Screenshot 2023-07-06 at 16 39 58

Please help to check.
This is my sample code:

func takeSnapshot(mapView: MapView, passedLocations: [[CLLocation]]) -> UIImage? {
        var overlays = [Overlay]()
        overlays.append(contentsOf: markers.compactMap { marker in
            if let url = URL(string: marker.type.iconURL) {
                return CustomMarker(coordinate: marker.location.coordinate, url: url)
            }
            return nil
        })
        passedLocations.forEach { locations in
            let coordinates = locations.map { $0.coordinate }
            if coordinates.count >= 2 {
                let path = Path(
                    coordinates: coordinates
                )
                path.strokeColor = UIColor(red: 0.376, green: 0.439, blue: 0.941, alpha: 1)
                path.strokeWidth = 3
                path.fillColor = .clear
                overlays.append(path)
            }
        }

        let center = mapView.cameraState.center
        let zoom = mapView.cameraState.zoom
        let snapshotCamera = SnapshotCamera(lookingAtCenter: center, zoomLevel: zoom > 20 ? 20 : zoom)

        if let styleURL = URL(string: StyleURI.streets.rawValue) {
            let options = SnapshotOptions(
                styleURL: styleURL,
                camera: snapshotCamera,
                size: mapView.bounds.size)

            options.overlays = overlays
            let snapshot = Snapshot(
                options: options,
                accessToken: MapBoxResource.accessToken
            )
            return snapshot.image
        }
        return nil
    }

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the Snapshot class and the Snapshot#image access shown in the sample. Reproduce the warning with the provided takeSnapshot flow, then trace the image-loading path. Done means the snapshot can be obtained without synchronous URL loading on the main thread and the reported image behavior remains intact.

Written by the indexing model from the issue text.

Assessment

Tech stack
swift
Domain
mobile-dev
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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