原创 利用polyline多段线绘制曲线

Canvas对象的Polyline函数可以用来非常简单地显示一些曲线.本例子分别用sin,cos和ramdom函数填充TPoint对象,然后
调用Canvas->Polyline,在窗体上显示相应的曲线.代码和显示效果图如下:

void __fastcall TForm1::Button3Click(TObject *Sender)
{
  TPoint sinp[360+1];
  TPoint cosp[360+1];
  TPoint ranp[360+1];
  int i;

  Randomize;//初始化随机数种子

  for (i=0; i<360; i++) {
  sinp.x=20+i;
  sinp.y=100+100*Sin(3.1415926*i/180);//SIN曲线
  cosp.x=20+i;
  cosp.y=100+100*Cos(3.1415926*i/180);//COS曲线
  ranp.x=20+i;
  ranp.y=Random(255);//用随机数填充
  }
  sinp[360]=sinp[359];
  cosp[360]=cosp[359];
  ranp[360]=ranp[359];
  this->Canvas->Pen->Color = clRed;//用红色画笔绘制SIN曲线
  this->Canvas->Polyline(sinp,360);
  this->Canvas->Pen->Color = clGreen;//用绿色画笔绘制COS曲线
  this->Canvas->Polyline(cosp,360);
  this->Canvas->Pen->Color = clGray;//用灰色画笔绘制随机数曲线
  this->Canvas->Polyline(ranp,360);
}