From: "Earl F. Glynn"
Subject: Re: Check if Image is Empty
Date: Tuesday, November 28, 2000 8:45 AM

"Alex Denissov" <denisso@uwidnsor.ca> wrote in message news:3a230a50_1@dnews...
>
> what about Image.Picture.Graphic.Empty?

It sure seems like this would be an easier way.

But if you put a TImage on a form
and do this, you'll get an Access Violation:

procedure TForm1.ButtonTestClick(Sender: TObject);
begin
  IF   Image1.Picture.Graphic.Empty
  THEN ShowMessage('Image is empty')
end;

The following seems to work OK:

procedure TForm1.ButtonTestClick(Sender: TObject);
begin
  IF   Image1.Picture.Graphic = NIL
  THEN ShowMessage('Image is empty')
end;

I'm not sure when the "Empty" property helps much.
You can create a TBitmap and assign it :

procedure TForm1.Button1Click(Sender: TObject);
begin
  Image1.Picture.Graphic := TBitmap.Create;
end;

This results in an "Empty" graphic, i.e.,
  Image1.Picture.Graphic.Empty is TRUE
but if you ever get rid of the bitmap,

Image1.Picture.Graphic := NIL

you can't use Empty.  You need to test for a NIL pointer
first.

--
efg

Earl F. Glynn
Overland Park, KS  USA

efg's Computer Lab:  http://www.efg2.com/Lab
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