From: koterski@NOSPAMgte.net (Steve Koterski)
Subject: Re: How to display a GIF type field in TDBImage
Date: 28 Jun 1999 00:00:00 GMT
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On Sun, 27 Jun 1999 15:38:52 GMT, ammar_aganovic@my-deja.com wrote:

>The subject should say it.
>It is a web based DB so it is filled with .gifs & .jpgs, but TDBImage
>reads .bmps by default. Is there a way to tell the TDBImage how to
>handle other formats? Do I have to stream?

The TDBImage component is predicated on graphics formats native to Windows,
like bitmap. GIF and JPEG are not native to the Windows environment. For
JPEG data, use a TJPEGImage component. For GIF images, though, you would
need a third-party component.

As TJPEGImage is not data-aware, you would need to copy the data from BLOB
column to component each time the dataset component's record pointer moves.
This is signified by the AfterScroll event. For example:

  procedure TForm1.Table1AfterScroll(DataSet: TDataSet);
  var
    MS: TMemoryStream;
    J1: TJPEGImage;
  begin
    J1 := TJPEGImage.Create;
    MS := TMemoryStream.Create;
    try
      TBlobField(DataSet.Fields[1]).SaveToStream(MS);
      MS.Seek(soFromBeginning, 0);
      with J1 do begin
        PixelFormat := jf24Bit;
        Scale := jsFullSize;
        Grayscale := False;
        Performance := jpBestQuality;
        ProgressiveDisplay := True;
        ProgressiveEncoding := True;
        LoadFromStream(MS);
      end;
      Image1.Picture.Graphic.Assign(J1);
    finally
      J1.Free;
      MS.Free;
    end;
  end;

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Steve Koterski     "An inventor is a person who makes an ingenious
Felton, CA         arrangement of wheels, levers and springs, and believes
                   it civilization."          -- Ernest Dimnet (1866-1954)