正弦曲线及其波动01

来源：互联网发布：安卓 node.js 编辑：程序博客网时间：2024/04/30 09:30

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Fourier series:<button onclick=movetox()> Click Me to Wave...</button> By Gu Laicheng, 14:17 2007-3-9

//由width:10pt;height:10pt; 控制圆的大小

var period   = 5;  //周期
var swing    = 100;  //振幅
var serials = 0;  //级数
var r        = 5;  //点圆半径
var density = 10;  //角速度
var x0       = 180;  //左起
var y0       = 280;  //中线
var offset   = 1;  //平移动量
var speed    = 20;  //平移动速度(s)

var pi = Math.PI; //3.1415926
var fillcolor = "#000000"; //小圆填充颜色
var strokecolor = "#000000"; //小圆边线颜色

var str = "";
var aa = 0;
var a=0;

// 以下除以3，是为了保持在屏幕上合适地显示5个周期
// 如果周期显示的多，而角速度小，可能造成点的个数太多，影响屏幕显示

lx = (360 * period)/2.5 ;
document.write("<v:line id=vml1 style='POSITION:absolute;Z-INDEX:3001;LEFT:"+x0+"px;TOP:"+(y0-swing-40)+"px' from='0,0' to='0,"+(swing*2+80)+"px' strokecolor='#0000DD' strokeweight='1px'/>");
document.write("<v:line id=vml2 style='POSITION:absolute;Z-INDEX:3003;LEFT:"+x0+"px;TOP:"+y0+"px' from='0,0' to='"+(lx+40)+",0px' strokecolor='#0000DD' strokeweight='1px'/>");

document.write("<v:line id=vml3 style='POSITION:absolute;Z-INDEX:3005;LEFT:"+x0+"px;TOP:"+(y0-swing)+"px' from='0,0' to='"+lx+",0px' strokecolor='#EEDDDD' strokeweight='1px'/>");
document.write("<v:line id=vml4 style='POSITION:absolute;Z-INDEX:3006;LEFT:"+x0+"px;TOP:"+(y0+swing)+"px' from='0,0' to='"+lx+",0px' strokecolor='#EEDDDD' strokeweight='1px'/>");

for(var a0=0;a0<=(360 * period);a0=a0+density){
aa = (a + a0) * pi/180 ;
kx=x0+a0/2.5;

  ky = y0 ;
  for(i0=0;i0<=serials;i0++) {
   ky = ky - swing * Math.sin((2*i0+1)*aa)/(2*i0+1)
  }
  str = str +"<v:oval id='_glc0"+a0+"' ";
  str = str +"style='position:absolute;left:"+kx+"px;top:"+ky+"px;width:"+r+"px;height:"+r+"px;z-index:4001;cursor:move' ";
  str = str +"fillcolor='"+fillcolor+"' strokecolor='"+strokecolor+"' strokeweight='2px' strokecolor='windowText [64]'/>";
}
document.write(str);

function movetox() {
theTime = setTimeout("movetox()", speed);
var today = new Date();

var display= today.toLocaleString();
status=""+a+"-"+display;
for(var a0=0;a0<=(360 * period);a0=a0+density){
  obj2=eval("_glc0"+a0);
  aa = (a + a0) * pi /180;
  yy = y0 ;
  for(i0=0;i0<=serials;i0++) {
   yy = yy - swing * Math.sin((2*i0+1)*aa)/(2*i0+1)
  }
  obj2.style.top=yy;
}
if(a>=(360 * period)) a = 0;
a=a+offset;
}

document.write("<br>");
document.write("周期:"+period+"<br>")
document.write("振幅:"+swing+"<br>")
document.write("级数:"+serials+"<br>")
document.write("点圆半径:"+r+"<br>")
document.write("角速度:"+density+"<br>")
document.write("左起:"+x0+"<br>")
document.write("中线:"+y0+"<br>")
document.write("平移动量:"+offset+"<br>")
document.write("平移动速度:"+speed+"<br>")

</script>

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