Delphi 的绘图功能[7] - PolyBezier、PolyBezierTo

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



{PolyBezier 至少需要四个点做参数; 不改变画笔的当前位置}

procedure TForm1.Button1Click(Sender: TObject);

var

  pts: array[0..3] of TPoint;

begin

  Canvas.Pen.Width := 2;

  Canvas.Pen.Color := clRed;



  pts[0].X := 10; pts[0].Y := 10;  {起点}

  pts[1].X := 60; pts[1].Y := 10;  {控制点1}

  pts[2].X := 10; pts[2].Y := 100; {控制点2}

  pts[3].X := 60; pts[3].Y := 100; {终点}



  Canvas.PolyBezier(pts);



  Canvas.Pen.Width := 1;

  Canvas.Pen.Color := clWhite;

  Canvas.LineTo(ClientWidth, ClientHeight);

end;



{PolyBezierTo 最少只需要需要三个点, 它把当前位置当作第一点; 会改变画笔的当前位置}

procedure TForm1.Button2Click(Sender: TObject);

var

  pts: array[1..3] of TPoint; {从 1 开始的, 就 3 个元素}

begin

  Canvas.Pen.Width := 2;

  Canvas.Pen.Color := clRed;



  Canvas.MoveTo(10 + 82, 10);           {起点}



  //pts[0].X := 10; pts[0].Y := 10;

  pts[1].X := 60 + 82; pts[1].Y := 10;  {控制点1}

  pts[2].X := 10 + 82; pts[2].Y := 100; {控制点2}

  pts[3].X := 60 + 82; pts[3].Y := 100; {终点}



  Canvas.PolyBezierTo(pts);



  Canvas.Pen.Width := 1;

  Canvas.Pen.Color := clBlue;

  Canvas.LineTo(ClientWidth, ClientHeight);

end;



end.


 
   




//效果图:

---

//绘制多条贝塞尔线时, 每条线的终点也是下条线的起点.



unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



{PolyBezier 绘制多条线时, 需要 3*x + 1 个点}

procedure TForm1.Button1Click(Sender: TObject);

var

  pts: array[0..6] of TPoint;

begin

  Canvas.Pen.Width := 2;

  Canvas.Pen.Color := clRed;



  pts[0].X := 10; pts[0].Y := 10;

  pts[1].X := 60; pts[1].Y := 10;

  pts[2].X := 10; pts[2].Y := 100;

  pts[3].X := 40; pts[3].Y := 100;

  pts[4].X := 100; pts[4].Y := 10;

  pts[5].X := 55; pts[5].Y := 99;

  pts[6].X := 70; pts[6].Y := 10;



  Canvas.PolyBezier(pts);

end;



{PolyBezierTo 绘制多条线时, 需要 3*x 个点}

procedure TForm1.Button2Click(Sender: TObject);

var

  pts: array[1..6] of TPoint;

begin

  Canvas.Pen.Width := 2;

  Canvas.Pen.Color := clRed;



  Canvas.MoveTo(10 + 82, 10);



  //pts[0].X := 10; pts[0].Y := 10;

  pts[1].X := 60 + 82; pts[1].Y := 10;

  pts[2].X := 10 + 82; pts[2].Y := 100;

  pts[3].X := 40 + 82; pts[3].Y := 100;

  pts[4].X := 100 + 82; pts[4].Y := 10;

  pts[5].X := 55 + 82; pts[5].Y := 99;

  pts[6].X := 70 + 82; pts[6].Y := 10;



  Canvas.PolyBezierTo(pts);

end;



end.


 
   




//效果图:

---