Canvas
lazarus / 9-Editor

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Leonardo · 2007-07-21 02:12

Using the Object Canvas.Ellipse, I observed that when I minimize the
window, the pictures that were drawn in this form dissappear. What can
I have to do to correct this??

A example:

procedure TForm1.FormMouseDown(Sender: TOBject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  Canvas.Ellipse(X-10,Y-10,X+10,Y+10);
end;

Thanks

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antonio · 2007-07-21 03:19

You must have a bitmap to back buffer the image, or redraw the ellipse
at each OnPaint form event.

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eric · 2007-07-21 09:58

Normally, whenever you draw something on a canvas, you should put the
drawing code in the OnPaint event of the object you're drawing on.

Eric