Declaration

TIETIFTagsReader = class;

Description

TIETIFTagsReader allows reading of single tags from a TIFF file or stream.

See also: TIETIFFHandler for a more powerful TIFF handling class.

Methods and Properties

Examples

Var
  Tags: TIETIFTagsReader;
...
Tags := TIETIFTagsReader.CreateFromFile('input.tif', 0);  // read tags of the first image (page)
If Tags.TagExists(269) then
  DocumentName := Tags.GetString(269);  // 269 is the document name
If Tags.TagExists(285) then
  Pagename := Tags.GetString(285);  // 285 is the page name
Tags.free;

// Read EXIF tags saved by Canon cameras
var
  ms: TMemoryStream;
  tagReader1, tagReader2, tagReader3: TIETifTagsReader;
  i: integer;
  // some Canon tags
  m_nMacroMode, m_nLenghtTimer, m_Quality: integer;
  m_ImageType: string;
begin
  with ImageEnView1 do
  begin
    IO.LoadFromFile('Capture_00006.JPG');
    with IO.Params.JPEG_MarkerList do begin
      i := IndexOf( JPEG_APP1 );
      if i>=0 then
      begin
        // there are EXIF info
        ms := TMemoryStream.Create;
        ms.Write( MarkerData[i][6], MarkerLength[i] );  // bypass first 4 bytes (must contain 'Exif')
        ms.Position := 0;

        tagReader1 := TIETifTagsReader.CreateFromStream( ms, 0 );    // read TIFF's IFD

        tagReader2 := TIETifTagsReader.CreateFromIFD( tagReader1, 34665 );    // read IFD in tag 34665 (SubEXIF)

        tagReader3 := TIETifTagsReader.CreateFromIFD( tagReader2, $927c );    // read IFD in tag $927C (MarkerData - Canon IFD data)

        // read Canon EXIF tags
        m_nMacroMode := tagReader3.GetIntegerIndexed(1, 1);
        m_nLenghtTimer := tagReader3.GetIntegerIndexed(1, 2);
        m_Quality := tagReader3.GetIntegerIndexed(1, 3);
        m_ImageType := tagReader3.GetString(6);

        tagReader3.Free;
        tagReader2.Free;
        tagReader1.Free;

        ms.Free;
      end;
    end;
  end;
end;

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