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Date Posted: 14:07:36 10/29/01 Mon
Author: Tim Griffin
Subject: Re: Invalid Pointer Operation
In reply to: Michel 's message, "Re: Invalid Pointer Operation" on 12:26:38 10/27/01 Sat

Thanks Michel!

I had AGraphic defined as TDibGraphic instead of TJpegGraphic!

Please forward to me your thumbnails code also as the code below is simply doing a thumbnail and I would like very much to see your example.

Thanks again!

Tim
>
>Hi Tim,
>
>Just from the code it is hard to tell. The AGraphic,
>is it really a TJpegGraphic? Try using (AGraphic as
>TJpegGraphic) rather than TJpegGraphic(AGraphic) just
>as a safeguard.
>
>Also, try tracing in your unit finalization sections
>with the debugger. Are you global objects being
>properly freed?
>
>Best regards,
>
>Michel
>
>>The following Delphi 5 code generates a 1/2 size JPG
>>and produces an "Invalid Pointer Operation" upon
>>closing the program. This happens with our without
>>Delphi running. The problem does not occur if this
>>code is skipped.
>>
>>AGraphic is defined globally and Transform is defined
>>locally but the problem also occured when AGraphic was
>>also defined locally.
>>
>>Also, ImageScrollBox1 is enabled but not visable.
>>
>>Please advise.
>>
>>Thanks much!
>>
>> Transform := TResizeTransform.Create;
>>
>> ImageScrollBox1.LoadFromFile(InFileName,0);
>> AGraphic.assign(ImageScrollBox1.Graphic);
>> TJpegGraphic(AGraphic).SaveQuality :=
>>thumbs2jpgquality;
>>
>> h := ImageScrollBox1.Graphic.Height;
>> w := ImageScrollBox1.Graphic.Width;
>>
>> ratio := 0.5;
>>
>> try
>> Transform.Width := trunc(w * ratio);
>> Transform.Height := trunc(h * ratio);
>> Transform.ApplyOnDest(AGraphic,
>>ImageScrollBox1.Graphic);
>>
>> ImageScrollBox1.SaveToFile(OutFileName);
>> finally
>> Transform.Free;
>> end;

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