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Add style to your application implementing an easter egg (Views: 100)


Problem/Question/Abstract:

Many world class applications implement some easter egg to give its author(s) credit, so why not to use this feature in your own applications?

Answer:

An easter egg is some piece of code that executes only when the user uses some special keystrokes, they are used frequently to give credit to the author(s) of some program.

For example in Delphi“s About box hold Shift + Alt and then type "team", you will expose an easter egg giving credit to Delphi Staff.

To create your own easter egg take this steps:

1.- Start a new Project

2.- Create the following private fields:

private
FEgg: string;
FCount: Integer;

FCount holds a count of Keystrokes.
FEgg holds the Keystrokes string.

3.- Create two constants

const
  EE_CONTROL: TShiftState = [ssCtrl, ssAlt];
  EASTER_EGG = 'SECRET';

EE_CONTROL contains the control keys that must be down when the user types the EASTER_EGG string

4.- In the OnCreate event of the form write

procedure TForm1.FormCreate(Sender: TObject);
begin
  FCount := 1;
  FEgg := EASTER_EGG;
end;

5.- In the OnKeyDown event of the form write

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  //Are the correct control keys down?
  if Shift = EE_CONTROL then
  begin
    //was the proper key pressed?
    if Key = Ord(FEgg[FCount]) then
    begin
      //was this the last keystroke in the sequence?
      if FCount = Length(FEgg) then
      begin
        //Code of the easter egg
        ShowMessage('Add your own code here!');
        //failure - reset the count
        FCount := 1; {}
      end
      else
      begin
        //success - increment the count
        Inc(FCount);
      end;
    end
    else
    begin
      //failure - reset the count
      FCount := 1;
    end;
  end;
end;

6.- Finally set the Form“s KeyPreview property to true.

Now you just have to replace the ShowMessage with Something more creative, use your imagination!

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