vim-55/src/gui_at_sb.c

346     Position	    oldtop, oldbot, newtop, newbot;
351     newtop = margin + (int)(tzl * sbw->scrollbar.top);
352     newbot = newtop + (int)(tzl * sbw->scrollbar.shown) + 1;
353     if (newbot < newtop + (int)sbw->scrollbar.min_thumb)
354 	newbot = newtop + sbw->scrollbar.min_thumb;
358     sbw->scrollbar.topLoc = newtop;
359     sbw->scrollbar.shownLength = newbot - newtop;
362 	if (newtop < oldtop)
363 	    FillArea(sbw, newtop, AT_MIN(newbot,	oldtop+1),1,0);
364 	if (newtop > oldtop)
365 	    FillArea(sbw, oldtop, AT_MIN(newtop,	oldbot	),0,0);
369 	    FillArea(sbw, AT_MAX(newtop, oldbot-1), newbot,  1,0);
372 	FillArea(sbw, newtop, newbot, 0, 1);