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| author | Přemysl Eric Janouch <p@janouch.name> | 2021-12-12 00:21:04 +0100 |
|---|---|---|
| committer | Přemysl Eric Janouch <p@janouch.name> | 2021-12-12 00:22:21 +0100 |
| commit | 2147dba8c433c48058b815f5cffd525dd11ddccc (patch) | |
| tree | 8bc8d8ad2148af2b362dc2a201b22b967061951d | |
| parent | 121c63e35e667a841380f4d405cc47ce0f50b2e9 (diff) | |
| download | fiv-2147dba8c433c48058b815f5cffd525dd11ddccc.tar.gz fiv-2147dba8c433c48058b815f5cffd525dd11ddccc.tar.xz fiv-2147dba8c433c48058b815f5cffd525dd11ddccc.zip | |
Add a comment about TIFF/EP vs libtiff
| -rw-r--r-- | fastiv-io.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/fastiv-io.c b/fastiv-io.c index ba2861f..372a9f0 100644 --- a/fastiv-io.c +++ b/fastiv-io.c @@ -1492,6 +1492,26 @@ open_libtiff(const gchar *data, gsize len, const gchar *path, GError **error) if (!tiff) goto fail; + // In Nikon NEF files, IFD0 is a tiny uncompressed thumbnail with SubIFDs-- + // two of them JPEGs, the remaining one is raw. libtiff cannot read either + // of those better versions. + // + // TODO(p): If NewSubfileType is ReducedImage, and it has SubIFDs compressed + // as old JPEG (6), decode JPEGInterchangeFormat/JPEGInterchangeFormatLength + // with libjpeg-turbo and insert them as the starting pages. + // + // This is not possible with libtiff directly, because TIFFSetSubDirectory() + // requires an ImageLength tag that's missing, and TIFFReadCustomDirectory() + // takes a privately defined struct that cannot be omitted. + uint32_t subtype = 0; + uint16_t subifd_count = 0; + const uint64_t *subifd_offsets = NULL; + if (TIFFGetField(tiff, TIFFTAG_SUBFILETYPE, &subtype) && + (subtype & FILETYPE_REDUCEDIMAGE) && + TIFFGetField(tiff, TIFFTAG_SUBIFD, &subifd_count, &subifd_offsets) && + subifd_count > 0 && subifd_offsets) { + } + do { // We inform about unsupported directories, but do not fail on them. GError *err = NULL; |