DitherImageTag   1623 magick/quantize.c           proceed=SetImageProgress(image,DitherImageTag,(MagickOffsetType) y,
DitherImageTag   1837 magick/quantize.c       proceed=SetImageProgress(image,DitherImageTag,p->offset,p->span);
DitherImageTag   1653 magick/threshold.c           proceed=SetImageProgress(image,DitherImageTag,progress++,image->rows);