Scalabium Software
Knowledge for your independence'.
Home Delphi and C++Builder tips

#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;

Published: January 17, 2000

See also

	Metafile Convert
	SMExport suite
	ABA Picture Convert
	SMImport suite
	SMMsg suite
	Protected Storage Viewer
	SMReport
	Paradox to MS Access converter
	Clarion to Text converter
	Paradox Password Recovery

Contact to webmaster