### Delphi 的繪圖功能[4] - 圓弧類圖形

```unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls;type  TForm1 = class(TForm)    Button1: TButton;    Button2: TButton;    Button3: TButton;    Button4: TButton;    Button5: TButton;    procedure FormCreate(Sender: TObject);    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);    procedure Button3Click(Sender: TObject);    procedure Button4Click(Sender: TObject);    procedure Button5Click(Sender: TObject);  end;var  Form1: TForm1;implementation{\$R *.dfm}var  btn: TButton;const  y1 = 10;  y2 = 80;{先設置畫筆畫刷}procedure TForm1.FormCreate(Sender: TObject);begin  Canvas.Pen.Width := 2;  Canvas.Pen.Color := clRed;  Canvas.Brush.Color := clWhite;end;{繪制橢圓; 橢圓的參數和矩形是一樣的}procedure TForm1.Button1Click(Sender: TObject);begin  btn := TButton(Sender);  Canvas.Ellipse(btn.Left, y1, btn.Left+btn.Width, y2);end;{根據矩形結構繪制橢圓}procedure TForm1.Button2Click(Sender: TObject);var  R: TRect; {定義一個矩形結構}begin  btn := TButton(Sender);  R := Rect(btn.Left, y1, btn.Left+btn.Width, y2);  Canvas.Ellipse(R);end;{繪制扇形}procedure TForm1.Button3Click(Sender: TObject);begin  btn := TButton(Sender);  Canvas.Pie(    btn.Left, y1,                             {矩形區域左上角}    btn.Left + btn.Width, y2,                 {矩形區域右下角}    btn.Left + btn.Width, y1 + (y2-y1) div 2, {扇形起點}    btn.Left + btn.Width div 2, y1            {扇形終點}  );end;{繪制弦, 參數同上}procedure TForm1.Button4Click(Sender: TObject);begin  btn := TButton(Sender);  Canvas.Chord(    btn.Left, y1,    btn.Left + btn.Width, y2,    btn.Left + btn.Width, y1 + (y2-y1) div 2,    btn.Left + btn.Width div 2, y1  );end;{繪制弧線, 參數同上}procedure TForm1.Button5Click(Sender: TObject);begin  btn := TButton(Sender);  Canvas.Arc(    btn.Left, y1,    btn.Left + btn.Width, y2,    btn.Left + btn.Width, y1 + (y2-y1) div 2,    btn.Left + btn.Width div 2, y1  );end;end.

//效果圖:```