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#59: How can I draw in the form caption?

If you want to draw a something in the title bar of the form, you must handle the WM_NCPAINT message. For example in the next code I show how you can output the form caption with italic font style:

type
  TForm1 = class(TForm)
  private
     procedure WMNCPaint(var Msg: TWMNCPaint); message WM_NCPAINT;
  end;

var Form1: TForm1;

implementation
{$R *.dfm}

procedure TForm1.WMNCPaint(var Msg: TWMNCPaint);
var ACanvas: TCanvas;
    intLeftShift, intTopShift: Integer;
begin
  inherited;

  ACanvas := TCanvas.Create;
  try
    {to retrieve the device context for the Form1 window}
    ACanvas.Handle := GetWindowDC(Form1.Handle);
    with ACanvas do
    begin
      Brush.Color := clActiveCaption;
      Font.Style := [fsItalic];

      {calculate the left coordinate for caption drawing}
      intLeftShift := GetSystemMetrics(SM_CYMENU) + GetSystemMetrics(SM_CXBORDER);
      {calculate the top coordinate for caption drawing}
      intTopShift := (GetSystemMetrics(SM_CYCAPTION) - Abs(Font.Height)) div 2 + 1;

      {output the caption string}
      TextOut(intLeftShift, intTopShift, Caption)
    end;
  finally
    {to release the device context}
    ReleaseDC(Form1.Handle, ACanvas.Handle);
    ACanvas.Free
  end;
end;