Delphi - how to move a control and refresh it

For a programming exercise in Delphi I want to scroll an image across the screen 1 pixel at a time and repaint it each time I move it, so it looks like it is actually moving. At the moment Delphi just draws it at the start and end, so it isn't smooth. I tried Repaint and also Refresh, but neither worked. I also tried making it visible and invisible to see if that would work, but no luck.

image1.Visible := true;
for i := 0 to 50 do
begin
   image1.Visible := false;
   image1.Left := image1.Left + 1;
   image1.Repaint(); // this doesn't work...
   for j :开发者_运维技巧= 0 to 1000000 do
   begin
      k := i + j; // do nothing code
   end; 
   image1.Visible := true;
end;

Does anyone know what I'm missing? Thanks.

A much better way to do this is to use a timer. In Delphi that means an object of class TTimer. Each time the timer fires you just increment the Left property. You probably want a counter that disables the timer once it has fired as many times as you desire.

procedure TForm1.FormClick(Sender: TObject);
var
  i: integer;
begin
  for i := 0 to 50 do
  begin
    image1.Left := image1.Left + 1;
    Application.ProcessMessages;
    sleep(100);
  end;
end;

You could also do Image1.Update instead of Application.ProcessMessages but then the application would stop responding to Windows messages; hence, it would "freeze". Anyhow, this is a very ugly way to do an animation (very ugly!), but if it is just an exercise, then ...