2023.04.13 09:32 "Re: [Tiff] TIffWriteDirectory() causes problems", by David C. Partridge

Grump

I changed the code so this is done before I write the image data:

                    //
                    TIFFSetDirectory(m_tiff, 0);
                    TIFFSetField(m_tiff, TIFFTAG_EXIFIFD, dir_offset_EXIF);
                    //TIFFCheckpointDirectory(m_tiff);
                    TIFFWriteDirectory(m_tiff);
                    TIFFSetDirectory(m_tiff, 0);

(is CheckpointDirectory() supposed to have the same effect as WriteDirectory followed by SetDirectory ???)

But while it solved the issue with scanline size, the main IFD ended up at the END of the file again:

C:\Users\amonra\jhove>jhove "C:\Users\amonra\Documents\Astrophotography\DSS Test Images\Covington\TestImages\Bias\MasterOffset_ISO200.tif"
Jhove (Rel. 1.26.1, 2022-07-14)
Date: 2023-04-13 10:17:09 BST
RepresentationInformation: C:\Users\amonra\Documents\Astrophotography\DSS Test Images\Covington\TestImages\Bias\MasterOffset_ISO200.tif
  ReportingModule: TIFF-hul, Rel. 1.9.3 (2022-04-22)
  LastModified: 2023-04-13 06:46:48 BST
  Size: 36040428
  Format: TIFF
  Version: 6.0
  Status: Well-Formed and valid
  SignatureMatches:
   TIFF-hul
  InfoMessage: Unknown TIFF IFD tag: 340
   ID: TIFF-HUL-12
   Offset: 36040184
  InfoMessage: Unknown TIFF IFD tag: 341
   ID: TIFF-HUL-12
   Offset: 36040196
  InfoMessage: Unknown TIFF IFD tag: 50002
   ID: TIFF-HUL-12
   Offset: 36040244
  InfoMessage: Unknown TIFF IFD tag: 50006
   ID: TIFF-HUL-12
   Offset: 36040256
  InfoMessage: Unknown TIFF IFD tag: 50007
   ID: TIFF-HUL-12
   Offset: 36040268
  InfoMessage: Unknown TIFF IFD tag: 50008
   ID: TIFF-HUL-12
   Offset: 36040280
  InfoMessage: Unknown TIFF IFD tag: 50009
   ID: TIFF-HUL-12
   Offset: 36040292
  InfoMessage: Unknown TIFF IFD tag: 50010
   ID: TIFF-HUL-12
   Offset: 36040304
  MIMEtype: image/tiff
  Profile: TIFF/IT-MP (ISO 12639:1998)
  TIFFMetadata:
   ByteOrder: little-endian
   IFDs:
    Number: 2
    IFD:
     Offset: 36039970
     Type: TIFF
     Entries:
      NisoImageMetadata:

etc.

I don't (now) issue any TIFF calls from Write() apart from TIFFScanlineSize(m_tiff) and TIFFWriteEncodedStrip().

I tried issuing another TIFFWriteDirectory call just before I called TIFFClose, just that resulted in a TIFF that I could read in my code without any issues, but when I tried to validate it using jHove I got:

C:\Users\amonra\jhove>jhove "C:\Users\amonra\Documents\Astrophotography\DSS Test Images\Covington\TestImages\Bias\MasterOffset_ISO200.tif" | more
Jhove (Rel. 1.26.1, 2022-07-14)
Date: 2023-04-13 10:27:10 BST
RepresentationInformation: C:\Users\amonra\Documents\Astrophotography\DSS Test Images\Covington\TestImages\Bias\MasterOffset_ISO200.tif
  ReportingModule: BYTESTREAM, Rel. 1.4 (2018-10-01)
  LastModified: 2023-04-13 10:26:44 BST
  Size: 36039970
  Format: bytestream
  Status: Well-Formed and valid
  SignatureMatches:
   TIFF-hul
  MIMEtype: application/octet-stream

Or if I specified -m TIFF-hul

:\Users\amonra\jhove>jhove -m TIFF-hul "C:\Users\amonra\Documents\Astrophotography\DSS Test Images\Covington\TestImages\Bias\MasterOffset_ISO200.tif"
| more
hove (Rel. 1.26.1, 2022-07-14)
Date: 2023-04-13 10:30:14 BST
RepresentationInformation: C:\Users\amonra\Documents\Astrophotography\DSS Test Images\Covington\TestImages\Bias\MasterOffset_ISO200.tif
ReportingModule: TIFF-hul, Rel. 1.9.3 (2022-04-22)
LastModified: 2023-04-13 10:26:44 BST
Size: 36039970
Format: TIFF
Version: 6.0
Status: Not well-formed
SignatureMatches:
  TIFF-hul
InfoMessage: Unknown TIFF IFD tag: 340
  ID: TIFF-HUL-12
  Offset: 222
InfoMessage: Unknown TIFF IFD tag: 341
  ID: TIFF-HUL-12
  Offset: 234
InfoMessage: Unknown TIFF IFD tag: 50002
  ID: TIFF-HUL-12
  Offset: 282
InfoMessage: Unknown TIFF IFD tag: 50006
  ID: TIFF-HUL-12
  Offset: 294
InfoMessage: Unknown TIFF IFD tag: 50007
  ID: TIFF-HUL-12
  Offset: 306
InfoMessage: Unknown TIFF IFD tag: 50008
  ID: TIFF-HUL-12
  Offset: 318
InfoMessage: Unknown TIFF IFD tag: 50009
  ID: TIFF-HUL-12
  Offset: 330
InfoMessage: Unknown TIFF IFD tag: 50010
  ID: TIFF-HUL-12
  Offset: 342
ErrorMessage: Unknown data type: Type = 30068, Tag = 25449
  ID: TIFF-HUL-3
  Offset: 422
ErrorMessage: Unknown data type: Type = 8307, Tag = 25970
  ID: TIFF-HUL-3
  Offset: 434
ErrorMessage: Tag 19752 out of sequence
  ID: TIFF-HUL-2
  Offset: 444
ErrorMessage: Unknown data type: Type = 25701, Tag = 19752
  ID: TIFF-HUL-3
  Offset: 446
ErrorMessage: Unknown data type: Type = 10606, Tag = 24937
  ID: TIFF-HUL-3
  Offset: 458
ErrorMessage: Tag 0 out of sequence
  ID: TIFF-HUL-2

How can I get that root IFD to be at the start of the file please?

Thanks, David