protected override void OnSave(Document input, Stream output, SaveConfigToken token, Surface scratchSurface, ProgressEventHandler callback) { if (callback == null) { input.SaveToStream(output); } else { UpdateProgressTranslator upt = new UpdateProgressTranslator(ApproximateMaxOutputOffset(input), callback); input.SaveToStream(output, new IOEventHandler(upt.IOEventHandler)); } }