[Àû¿ë´ë»ó: 0.74_SVN_new, DOSBox-x]

If set, allow the DOS demo or program to change the horizontal pel (panning) register per scanline.

Some early DOS demos use this to create waving or sinus effects on the picture.

Not very many VGA
chipsets allow this, so far, only ATI chipsets are known to support this effect. Disabled by default.