WinAPI: OffsetRect 移动矩形

本例效果图:

---

unit Unit1;

interface

uses
  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 Draw;
    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
  R: TRect;

procedure TForm1.Draw;
begin
  Refresh;
  Canvas.FillRect(R);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Button1.Caption := '绘制矩形';
  Button2.Caption := '上移';
  Button3.Caption := '下移';
  Button4.Caption := '左移';
  Button5.Caption := '右移';
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  R := Bounds(80, 60, 60, 60);
  Randomize;
  Canvas.Brush.Color := Random($FFFFFF);
  Draw;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  OffsetRect(R, 0, -10);
  Draw;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  OffsetRect(R, 0, 10);
  Draw;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  OffsetRect(R, -10, 0);
  Draw;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
  OffsetRect(R, 10, 0);
  Draw;
end;

end.