/*
 * lib physical v0.1 beta build 090301 copyright (c) 2009 ilwave ce. http://ilwave.spaces.live.com
 *
 * this class is part of lib - a javascript library which is still on designing, and is an extend copy of class "object" in lib.
 * before using this class, you might include lib.common.js and lib.physical.js first.
 *
 * 注意：本类需要 lib.common.js 的支持。
 *
 */
 
var physical = object.extend({

	/*
	 * 平滑滚动，生成坐标数组
	 *
	 * nfrom 滚动起点
	 * nto 滚动终点
	 * nsteps 平滑度，越大越平滑
	 * ntype 滚动类型 0 = 先快后慢, 1 = 先慢后快再慢
	 *
	 */

	smooth: function(nfrom, nto, nsteps, ntype)
	{
		var arrlist = [];
		
		switch (ntype) {
			
			case 1: {
				
				var npt = 0, ndata = 0;
			
				for (var i=1; i<=nsteps; i++) {

					npt = i/nsteps;
					npt != 0.5 && arrlist.push(nfrom + (nto - nfrom) * ((math.sqrt(math.abs(2 * npt - 1)) * (2 * npt - 1) / math.abs(2 * npt - 1) + 1) / 2));
					
				}
				
				break;
			}
			
			default: {
				
				for (var i=1; i<=nsteps; i++) {
					
					arrlist.push(nfrom + (nto - nfrom) * math.sqrt(i / nsteps));	
								
				}
				
			}
			
		}
		
		return arrlist;
	}

});