画方形 圆形等[1]

procedure TForm1.btn1Click(Sender: TObject);
begin
  Canvas.Pen.Color := clRed;
  Canvas.Pen.Width := 2;
  Canvas.MoveTo(0, 0);
  Canvas.LineTo(ClientWidth, ClientHeight);
end;

procedure TForm1.btn2Click(Sender: TObject);
begin
  Canvas.Brush.Color := clYellow;
  Canvas.FillRect(ClientRect);
end;

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    btn1: TButton;
    btn2: TButton;
    btn3: TButton;
    btn4: TButton;
    btn5: TButton;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure btn3Click(Sender: TObject);
    procedure btn5Click(Sender: TObject);
    procedure btn4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
var
 btn: TButton;
const
  y1 = 10;
  y2 = 80;

procedure TForm1.btn1Click(Sender: TObject);
begin
  btn := TButton(Sender);
  Canvas.Rectangle(btn.Left, y1, btn.Left+btn.Width, y2);
end;

procedure TForm1.btn2Click(Sender: TObject);
var
  r: TRect;
begin
  btn := TButton(Sender);
  r := Rect(btn.Left, y1, btn.Left+btn.Width, y2);
  Canvas.Rectangle(r);
end;

procedure TForm1.btn3Click(Sender: TObject);
begin
  btn := TButton(Sender);
  Canvas.RoundRect(btn.Left, y1, btn.Left+btn.Width, y2, 20, 20);
end;

procedure TForm1.btn4Click(Sender: TObject);
var
  r: TRect;
begin
  btn := TButton(Sender);
  r := Rect(btn.Left, y1, btn.Left+btn.Width, y2);
  Canvas.FrameRect(r);
end;
procedure TForm1.btn5Click(Sender: TObject);
var
  r: TRect;
begin
  btn := TButton(Sender);
  r := Rect(btn.Left, y1, btn.Left+btn.Width, y2);
  Canvas.DrawFocusRect(r);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Canvas.Pen.Color := clGreen;
  Canvas.Pen.Width := 2;
  Canvas.Brush.Color := clWhite;
end;

end.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    btn1: TButton;
    btn2: TButton;
    btn3: TButton;
    btn4: TButton;
    btn5: TButton;
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure btn3Click(Sender: TObject);
    procedure btn5Click(Sender: TObject);
    procedure btn4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
var
 btn: TButton;
const
  y1 = 10;
  y2 = 80;

procedure TForm1.btn1Click(Sender: TObject);
begin
  btn := TButton(Sender);
  Canvas.Ellipse(btn.Left, y1, btn.Left+btn.Width, y2);
end;

procedure TForm1.btn2Click(Sender: TObject);
var
  r: TRect;
begin
  btn := TButton(Sender);
  r := Rect(btn.Left, y1, btn.Left+btn.Width, y2);
  Canvas.Ellipse(r);
end;

procedure TForm1.btn3Click(Sender: TObject);
begin
  btn := TButton(Sender);
  Canvas.Pie(
    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;

procedure TForm1.btn4Click(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;

procedure TForm1.btn5Click(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;
procedure TForm1.FormCreate(Sender: TObject);
begin
  Canvas.Pen.Color := clGreen;
  Canvas.Pen.Width := 2;
  Canvas.Brush.Color := clWhite;
end;

end.