unit1.pas

学习Delphi最好的教材。通过一个个简单而实用的实例

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    ListBox1: TListBox;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
  Canvas.MoveTo(20,20);  //先把画笔移到点(20,20) ，直线的起点
  Canvas.LineTo(200,20); //画直线到(200,20)  ，直线的终点
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Canvas.Rectangle(20,40,200,60);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  Canvas.Ellipse(20,40,200,60);
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  if ListBox1.ItemIndex=0 then
  begin
    Canvas.MoveTo(20,20);  //先把画笔移到点(20,20) ，直线的起点
    Canvas.LineTo(200,20); //画直线到(200,20)  ，直线的终点
  end;
  if ListBox1.ItemIndex=1 then
  begin
    Canvas.Rectangle(20,40,200,60);
  end;
  if ListBox1.ItemIndex=2 then
  begin
    Canvas.Ellipse(20,40,200,60);
  end;
end;

end.