invertrectu.pas

DelphiWin32核心API参考光盘内容.是学习书籍中的源码,便于学习.

unit InvertRectU;

interface

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

type
  TForm1 = class(TForm)
    Image1: TImage;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var
  TheRect: TRect;     // holds the rectangular coordinates
begin
  {create a rectangle}
  SetRect(TheRect, 46, 40, 106, 100);

  {invert the pixels inside the rectangle}
  InvertRect(Image1.Canvas.Handle, TheRect);

  {repaint the new image}
  Image1.Refresh;
end;

end.