obtainKey method

  1. @override
Future<PocketBaseImageProvider> obtainKey(
  1. ImageConfiguration configuration
)
override

Converts an ImageProvider's settings plus an ImageConfiguration to a key that describes the precise image to load.

The type of the key is determined by the subclass. It is a value that unambiguously identifies the image (including its scale) that the loadImage method will fetch. Different ImageProviders given the same constructor arguments and ImageConfiguration objects should return keys that are '==' to each other (possibly by using a class for the key that itself implements ==).

If the result can be determined synchronously, this function should return a SynchronousFuture. This allows image resolution to progress synchronously during a frame rather than delaying image loading.

Implementation

@override
Future<PocketBaseImageProvider> obtainKey(ImageConfiguration configuration) {
  final Color color = this.color ?? Colors.transparent;
  final double scale = this.scale ?? configuration.devicePixelRatio ?? 1.0;

  final double logicWidth = (size ?? configuration.size)?.width ?? 100;

  final double logicHeight = (size ?? configuration.size)?.height ?? 100;

  // Returns a new PocketBaseImageProvider instance configured with the derived values.
  // This new instance serves as the cache key.
  return SynchronousFuture<PocketBaseImageProvider>(
    PocketBaseImageProvider(
      client: client,
      filename: filename,
      recordId: recordId,
      recordCollectionName: recordCollectionName,
      scale: scale,
      color: color,
      pixelWidth: (logicWidth * scale).round(),
      pixelHeight: (logicHeight * scale).round(),
      expireAfter: expireAfter,
      token: token,
      autoGenerateToken: autoGenerateToken,
      size: size,
    ),
  );
}