procedure TForm1.FormPaint(Sender: TObject);
var
trect1:trect;
begin
canvas.Pen.Color:=clred;
//canvas.Pen.Width:=1; //指定画笔的宽度
//canvas.Pen.Style:=psDashDotDot;//指定画笔的样式
with canvas do
begin
     pen.color:=clnavy;
     //画折线
     polyline([Point(120,10),Point(80,110),Point(180,50),Point(60,50),Point(160,110),Point(120,10)]);
     pen.Color:=clred;
     //arc绘制弧形曲线
     arc(220,10,420,110,220,10,420,10);
     //moveto作用是将画笔移到指定位置
     moveto(100,160);
     //lineto画一条到指定位置的直线段，线段起始位置由画布对象的Penpos属性值即画笔的当前位置确定。
     lineto(10,250);
     pen.color:=clolive;
     //画圆或者椭圆
     ellipse(110,160,300,250);
     pen.color:=clteal;
     //roundrect圆角矩形
     roundrect(310,160,400,250,50,240);
     pen.Color:=clblue;
     //rectangle绘制矩形
     rectangle(410,160,500,250);
     pen.Color:=clYellow;
     Textout(100,250,'Delphi，你好');
     trect1.Left:=220;
     trect1.Top:=250;
     TextRect(trect1,230,320,'Delphi中的画笔');

end;
end;

源代码