ScrollMaxX = (DisplayMaxX + border1_offset) * TILEX - pseudo_sxsize;
ScrollMaxY = (DisplayMaxY + border1_offset) * TILEY - pseudo_sysize;
ScrollMaxX = (DisplayMaxX + border1_offset) * TILEX - pseudo_sxsize;
ScrollMaxY = (DisplayMaxY + border1_offset) * TILEY - pseudo_sysize;