上个预览图先：

代码：
unit Unit1;

interface

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

type
 TForm1 = class(TForm)
 Button1: TButton;
 Timer1: TTimer;
 Edit1: TEdit;
 procedure Timer1Timer(Sender: TObject);
 procedure FormCreate(Sender: TObject);
 procedure Button1Click(Sender: TObject);
 end;

var
 Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
 Timer1.Enabled := False;
 Timer1.Interval := 100;
 Button1.Default := True;
 Button1.Caption := '开始';
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
 Timer1.Enabled := not Timer1.Enabled;
 if Timer1.Enabled then Button1.Caption := '停止'
 else Button1.Caption := '开始';
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
 pt: TPoint;
 c: TColor;
begin
 GetCursorPos(pt);
 c := GetPixel(GetDC(0), pt.X, pt.Y);
 Self.Color := c;
 Edit1.Text := Format('#%.6x', [c]);
end;

end.