Question

My program is doing a time consuming task, and I would like to display a TImage in the middle of the application window, but it will not stay on top – my VST is always on top. However, when I use a TPanel, it stays on top? How can I make my TImage do that?

In fact, a solution that applies to all controls would be splendid 🙂

Thanks!

Answer 1

You need a windowed control (that is, a control with a window handle, or a “proper” control) to display your message, because a non-windowed control cannot be visible above a windowed control. The easiest solution is to place the TImage in a TPanel and set Image1.Align := alClient and Panel1.BorderStyle := bsNone.

If you wish to draw a semi-transparent bitmap on top of your ordinary controls, you can do like I always do:

procedure TForm1.Button1Click(Sender: TObject);
var
  bm: TBitmap;
  png: TPngImage;
begin
  // The form contains a hidden TPanel (somewhere on the form)
  // with a TImage (alClient).

  // png is a PNG image with an alpha channel
  png := TPngImage.Create;
  try
    png.LoadFromFile('C:\Users\Andreas Rejbrand\Pictures\alpha.png');
    // Create bitmap of form and blend PNG on it
    bm := GetFormImage;
    try
      bm.Canvas.Draw(0, 0, png);
      Image1.Picture.Bitmap := bm;
    finally
      bm.Free;
    end;
    Panel1.Align := alClient;
    Panel1.BringToFront;
    Panel1.Show;
  finally
    png.Free;
  end;
end;