obtainKey method

@override Future<_SvgImageProviderKey> obtainKey(ImageConfiguration configuration)

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<_SvgImageProviderKey> obtainKey(ImageConfiguration configuration) {
  final color = this.color ?? Colors.transparent;
  final scale = this.scale ?? configuration.devicePixelRatio ?? 1.0;
  final logicWidth = size?.width ?? configuration.size?.width ?? 100;
  final logicHeight = size?.height ?? configuration.size?.height ?? 100;

  return SynchronousFuture<_SvgImageProviderKey>(
    _SvgImageProviderKey(
      path: path,
      scale: scale,
      color: color,
      source: source,
      pixelWidth: (logicWidth * scale).round(),
      pixelHeight: (logicHeight * scale).round(),
    ),
  );
}