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Date Posted: 06:39:38 09/23/03 Tue
Author: Michel
Subject: Re: Invalid class type cast
In reply to: gawan 's message, "Invalid class type cast" on 18:54:16 09/20/03 Sat


HI Gawan,

This means that the current image in TPicture.Graphic is not a TDibGraphic. But it can be converted. Change your code to,


Graphic := TDibGraphic.Create;
...
Graphic.Assign(Image.Picture.Graphic);

do the transform

Image.Picture.Graphic := Graphic;

Graphic.Free;


Best regards,

Michel

>Hi I am trying to make my first test application, but
>when trying to do as follows I get a "Invalid class
>type cast" error from the line where I try to assign
>TImage.Picture.Graphic to a TDibGraphic:
>
>uses
> EnDiGrph, EnTransf;
>
>procedure TForm1.Button2Click(Sender: TObject);
>var
> Transform: TResizeTransform;
> Graphic: TDibGraphic;
> WO, HO: Integer;
> Prop: Double;
>begin
> WO := Image1.Picture.Width;
> HO := Image1.Picture.Height;
> Prop := WO / 150;
> Graphic := Image1.Picture.Graphic as TDibGraphic;
> Transform := TResizeTransform.Create;
> try
> Transform.Width := round(Prop * WO);
> Transform.Height := round(Prop * HO);
> Transform.InterPolated := True;
> Transform.Filter := ifBSpline;
> Transform.Apply(Graphic);
> Image1.Invalidate;
> finally
> Transform.Free;
> end;
>end;
>
>I cannot find the cause of the problem, this code is
>mostly copied from the example in the help file. I
>have the trial version and Delphi 7.

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