Function decodeRegionAtBestLevel

Select an overview for a requested output size and decode its scaled ROI.

imageio.tiff.TiffDecodeResult decodeRegionAtBestLevel(
  transport.source.ByteSource source,
  ulong x,
  ulong y,
  ulong width,
  ulong height,
  ulong targetWidth,
  ulong targetHeight
) @safe;