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How to retrieve and display a TJPEGImage from a Paradox blob field (Views: 48)


Problem/Question/Abstract:

How to retrieve and display a TJPEGImage from a Paradox blob field

Answer:

Solve 1:

Here's some code to fill a TImage on a form with a JPEGImage from a Paradox blob field:

var
  Stream1: TBlobStream;
  Photo: TJPEGImage;
begin
  Stream1 := TBlobStream.Create(Table1.FieldByName('YourFieldName') as TBlobField, bmRead);
  Photo := TJPEGImage.create;
  try
    Photo.LoadFromStream(Stream1);
    Image1.Picture.Assign(Photo);
  finally
    Stream1.Free;
    Photo.Free;
  end;
end;


Solve 2:

Here is an example showing use of the TJPEGImage to display JPEG images in a TImage component. The JPEG data is stored in a Paradox BLOB field, and this routine is executed when the record pointer is moved in the table in order to display each new record's BLOB field contents.

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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