Canvas does not allow drawing.

From: Skybuck Flying (nospam_at_hotmail.com)
Date: 12/31/04 

Date: Fri, 31 Dec 2004 07:20:01 +0100

Hi,

Start a new application and place an Timage on the form and load a little
picture into it.

Then place a timer on the form and set the interval to 50 or so.

Then paste this code into the timer event handler.

Then simply let it run a while. (It will draw the little picture onto the
desktop)

After a while it will "crash" Debugger notification exception (?) and say:
"Canvas does not allow drawing".. etc.

Why does this happen and what is the solution (if any ;)) ?

procedure TForm1.Timer1Timer(Sender: TObject);
var
 DesktopCanvas : TCanvas;
begin
 DesktopCanvas := TCanvas.Create;

 DesktopCanvas.Handle := GetDC(0);

 DesktopCanvas.Draw( 50, 50, Image1.Picture.Graphic );

 DesktopCanvas.Destroy;
end;

Bye,
  Skybuck

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