LibTIFF’s naming is confusing - there really isno such thing as a “directory “. There are IFDs, and there are SubIFDs. And they are completely different from each other.
W. Kemp Watson Objective Pathology Services Toronto, Canada http://www.objectivepathology.com [email protected] tel. +1 (647) 783-4431 > On Dec 9, 2022, at 9:17 PM, L. E. Segovia via Tiff <[email protected]> > wrote: > > Yes, I did this, but not even GIMP recognises such multi-page files. > > On a related matter, judging from > https://linux.die.net/man/3/tiffsetdirectory, there should be a way to > not need to tamper with TIFFTAG_SUBIFD, i.e. using TIFFReadDirectory > sequentially. In fact, it was the approach we were using up to now. > > That brings me a few questions to mind: > > - Does anyone know if that's the intended use of TIFFReadDirectory? If > so, wasn't the function intended to seek into the next directory on its own? > - Alternatively, are we supposed to use TIFFSetSubdirectory before each > TIFFReadDirectory? (getting the offsets with TIFFGetField) > > Best, > > amyspark > >> On 09/12/2022 10:52, [email protected] wrote: >> Hello amyspark, >> >> My understanding is that you set the magic TIFFTAG_SUBIFD tag on a >> directory with an $n element array of offsets, all initialized to 0, >> and then the next $n TIFF directories you write will appear as >> subdirectories of this directory, with the offsets filled in for you. >> >> Or that's what I did here and it seems to work for me: >> >> https://github.com/libvips/libvips/blob/master/libvips/foreign/vips2tiff.c#L2127-L2141 >> >> John >> >>> On Fri, 9 Dec 2022 at 12:26, <[email protected]> wrote: >>> >>> The page I followed when implementing TIFF subframe writing is: >>> >>> https://stackoverflow.com/questions/11959617/in-a-tiff-create-a-sub-ifd-with-thumbnail-libtiff >>> >>> HTH >>> Paavo >>> >>> >>> -----Original Message----- >>> From: Tiff <[email protected]> On Behalf Of L. E. Segovia via >>> Tiff >>> Sent: reede, 9. detsember 2022 03:29 >>> To: [email protected] >>> Subject: [Tiff] How to write multi-file TIFFs >>> >>> Hi all, >>> >>> I'm writing to ask about how to create a TIFF with multiple sub-images. >>> Our writing code at Krita is unable to create this kind of files, creation >>> fails with these lines logged: >>> >>>> krita.file: "TIFFLinkDirectory: Error fetching directory count" >>>> krita.file: "TIFFRewriteDirectory: Error fetching directory count" >>> >>> A breakpoint on the TIFF error writing routine shows that both are issued >>> the moment I call TIFFWriteDirectory for the second and further layers. >>> TIFFCreateDirectory, which I saw suggested in tif_overview.c, does not have >>> an effect here. >>> >>> Does anyone know the correct incantations to create this kind of files? >>> I'm running LibTiff 4.4.0 at present. >>> >>> Best, >>> >>> amyspark >>> >>> -- >>> amyspark 🌸 https://www.amyspark.me >>> _______________________________________________ >>> Tiff mailing list >>> [email protected] >>> https://lists.osgeo.org/mailman/listinfo/tiff >>> >>> _______________________________________________ >>> Tiff mailing list >>> [email protected] >>> https://lists.osgeo.org/mailman/listinfo/tiff >> _______________________________________________ >> Tiff mailing list >> [email protected] >> https://lists.osgeo.org/mailman/listinfo/tiff > > -- > amyspark 🌸 https://www.amyspark.me > _______________________________________________ > Tiff mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/tiff _______________________________________________ Tiff mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/tiff
