unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, ExtCtrls, StdCtrls, XPMan;type  TForm1 = class(TForm)    Bevel1: TBevel;    Bevel2: TBevel;    Bevel3: TBevel;    Bevel4: TBevel;    Button1: TButton;    RadioGroup1: TRadioGroup;    Button2: TButton;    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;      Shift: TShiftState; X, Y: Integer);    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,      Y: Integer);    procedure FormMouseUp(Sender: TObject; Button: TMouseButton;      Shift: TShiftState; X, Y: Integer);    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);  private    start:Boolean;    OX,OY:Integer;    { Private declarations }  public    { Public declarations }  end;var  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;  Shift: TShiftState; X, Y: Integer);begin  start:=true;  case RadioGroup1.ItemIndex of    0: ; //nothing    1,2,3,4,    5:  begin          OX:=X;          OY:=Y;        end;  end;  Self.Canvas.MoveTo(X,Y);　　　　//设置画笔的起始位置end;procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,  Y: Integer);begin  if start then  begin  case RadioGroup1.ItemIndex of   //根据TRadioGroup组件的索引号进行操作    0: begin         Canvas.Pen.Color := clWindowText;    //将画笔设置成黑色         self.Canvas.LineTo(X,Y);　　　　　　　 //鼠标移动时在窗体上画线       end;    1,2,3,4: Canvas.Pen.Color := clWindowText; //将画笔设置成黑色    5: begin         Canvas.Pen.Color := form1.Color;   //将画笔颜色设置成窗体颜色         Canvas.Brush.Color := form1.Color; //将画刷颜色设置成窗体颜色         Canvas.Rectangle(X-2,Y-2,X+2,Y+2); //对窗体进行擦除       end;  end;  end;end;procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;  Shift: TShiftState; X, Y: Integer);begin  start:=false;  case RadioGroup1.ItemIndex of     0: ;    1:  Canvas.Arc(OX,OY,x,y,oX,oY,X,y);  //画弧形    2:  Canvas.Ellipse(Rect(OX,OY,x,y));  //画椭圆    3:  Canvas.Rectangle(OX,OY,x,y);      //画矩形    4:  begin　　　　　　　　　　　　　　　　 //画椭圆            if abs(x-OX)<abs(y-OY) then              Canvas.Ellipse(OX,OY,OX+abs(OX-x),OY+abs(OX-x))  //以X值的长度画椭圆         else              Canvas.Ellipse(OX,OY,OX+abs(OY-y),OY+abs(OY-y)); //以Y值的长度画椭圆        end;  end;end;procedure TForm1.Button2Click(Sender: TObject);begin  Close;end;procedure TForm1.Button1Click(Sender: TObject);begin  form1.canvas.FillRect(Rect(9,9,392,288));end;end.