WinAPI: InvertRect - 翻转矩形中像素的颜色

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;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



var

  R: TRect;



procedure TForm1.FormCreate(Sender: TObject);

begin

  Button1.Caption := '绘制矩形';

  Button2.Caption := '反色';

  Self.Color := clWhite;

end;



procedure TForm1.Button1Click(Sender: TObject);

begin

  R := Bounds(20, 20, 150, 100);

  Randomize;

  Canvas.Brush.Color := Random($FFFFFF);

  Canvas.Pen.Color := Random($FFFFFF);

  Canvas.Pen.Width := 10;

  Canvas.Rectangle(R);

end;



procedure TForm1.Button2Click(Sender: TObject);

begin

  InvertRect(Canvas.Handle, R);

end;



end.