How can I make my form resize more smoothly?

Question

When resizing a form with many controls, the form looks bad because of flickering. What are some tips to have a smoother form resizing?

Answer 1

Try using WM_SETREDRAW (not LockWindowUpdate).

You might also have a look at DeferWindowPos.

Answer 2

Complex forms are often made up of nested panels, and the repaint process may cause flickering. If this is the case with your project there are two easy solutions that might help:

1. Disable the property FullRepaint on your panels.
2. Enable the property DoubleBuffered on your form. You won't find this property on the object inspector, so put DoubleBuffered := true; in FormCreate.

Answer 3

I've got around this as follows:

1. In the 'OnResize' event of the form, have a routine to hide all child controls and then start a timer with a tick of about 500ms.
2. When the timer fires, disable it and then set all child controls to visible.

By playing around with this activity you get a form that goes blank whilst you are sizing it, but then populates itself neatly when you 'let go'.

Bri

Answer 4

procedure TForm1.WMEnterSizeMove(var Message:TWMMove);
begin
  Self.DisableAlign;
end;

procedure TForm1.WMExitSizeMove(var Message:TWMMove);
begin
  Self.EnableAlign;
end;