Providing alternate assets to MediaPicker

Roy · June 2022

I am trying to configure a custom MediaPicker view to display/load specific assets when using a lens.

Issue is, from what I've tried, the only way to create a SCCameraKitLensMediaPickerProvider is to create the default LensMediaPickerProviderPhotoLibrary.

There is no ability to fully implement a subclass without further information regarding required protocol implementations for functions in LensMediaPickerProviderPhotoLibrary such as loadAndApplyOriginalMediaFromAsset. If i were to implement it, where can i get more info on how to apply resource to lens as a part of this protocol method's job.

//SCCameraKitLensMediaPickerProvider.h
- (void)loadAndApplyOriginalMediaFromAsset:(id<SCCameraKitLensMediaPickerAsset>)asset
                                completion:(nullable void (^)(void))completion
    NS_SWIFT_NAME(loadAndApplyOriginalMedia(from:completion:));

I currently have it set up like the CameraKit sample project , and am using a custom MediaPicker to select items for a Lens via app (iOS), as is shown in sample code:

//CameraViewController.swift
cameraView.mediaPickerView.provider = cameraController.lensMediaProvider
cameraView.mediaPickerView.delegate = cameraController
cameraController.lensMediaProvider.uiDelegate = cameraView.mediaPickerView

//CameraController.swift
/// Media provider for CameraKit.
    public var lensMediaProvider: LensMediaPickerProvider = LensMediaPickerProviderPhotoLibrary(defaultAssetTypes: [.image, .video])
...
/// Configures the data provider for lenses. Subclasses may override this to customize their data provider.
    /// - Returns: a configured data provider.
    open func configureDataProvider() -> DataProviderComponent {
        // By default, CameraKit will handle data providers (such as device motion),
        // but if you want to handle specific data provider(s), pass them in here, example:
        DataProviderComponent(
            deviceMotion: nil, userData: UserDataProvider(), lensHint: nil, location: nil,
            mediaPicker: lensMediaProvider)
    }

What is the suggested way to go about solving this? Providing custom media to the MediaPickerView vs using the default Provider?

Thanks!

Roy · June 2022

Perhaps I found it - could it be this?

NS_SWIFT_NAME(LensMediaPickerProviderMediaApplicationDelegate)
/// Delegate responsible for applying media to a lens. This should not be implemented directly.
/// @note If you create a custom provider, you'll need to call the methods here from your provider. See notes on
/// provider.uiDelegate for more details.
@protocol SCCameraKitLensMediaPickerProviderMediaApplicationDelegate <NSObject>

/// Notifies lenses that the media picker provider has loaded the full resolution version of an asset and is ready for
/// it to be applied.
/// @param provider the provider sending the reequest
/// @param asset the asset provided by the provider
/// @param url the URL to a full-resolution image or video for lenses to apply
/// @param metadata any metadata associated with the asset
- (void)mediaPickerProvider:(id<SCCameraKitLensMediaPickerProvider>)provider
    requestedApplicationOfOriginalAssets:(id<SCCameraKitLensMediaPickerAsset>)asset
                                     url:(NSURL *)url
                                metadata:(SCCameraKitLensMediaPickerAssetMetadata)metadata;

@end

Roy · June 2022

I've been able to create my own provider class that conforms to LensMediaPickerProvider.

My last issue now, is to understand how I can create/get a SCCameraKitLensMediaPickerAssetMetadata value/obj to pass to the media picker provider delegate in the provider requestedApplicationOfOriginalAssets method.

There really isn't too much documentation about it either than this -
https://kit.snapchat.com/reference/CameraKit/ios/1.13.0/SCSDKCameraKit/Type Definitions/SCCameraKitLensMediaPickerAssetMetadata.html

Any clue?

Roy · June 2022

Seem to have found the missing piece - here is the info:

/// Metadata for a media asset
typedef struct {
    // If the asset is an image with a face present, a rect specifying the position of the face. Otherwise CGRectZero
    CGRect faceRect;
} SCCameraKitLensMediaPickerAssetMetadata;

For my use case, I believe it can be any value.

Roy · June 2022

Got it to work!

After some more attempts, I ended up creating a custom lense media provider, and implemented the protocol methods.

Then, you can pretty much handle things however you want.

DM me if need help on this!

Jose Aguerre · July 30

Hi, I know it's been two years since this but was wondering if you could help me. Don't know how to DM here sorry

I'm trying to apply the green screen template lens in my app and effectively select an image with the media picker for the background without success.

We have it set up so the provider uses the default picker handled by the SDK. I can apply the lens, but the picker is not shown. I also saw the template has a tap detection script to hide/show the media picker but nothing happens on my app when tapping.

Do you know if there's a way to achieve this? Do I need to implement something more custom as you did?

Thanks!

Providing alternate assets to MediaPicker

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