fix(png): Write out proper tiff header version in png EXIF blobs (#3984)

When writing out EXIF headers in PNG files, the `tiff_version` field wasn't handling endianness properly. This lead to some tools like `exiv2` refusing to process the file at all[1] [1] Exiv2/exiv2#2745 --------- Signed-off-by: Jesse Yurkovich <[email protected]>
AcademySoftwareFoundation · Sep 13, 2023 · c1d8fe6 · c1d8fe6
1 parent 069e1d9
commit c1d8fe6
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/src/libOpenImageIO/exif.cpp b/src/libOpenImageIO/exif.cpp
@@ -1302,6 +1302,8 @@ encode_exif(const ImageSpec& spec, std::vector<char>& blob,
     TIFFHeader head;
     head.tiff_magic   = (endianreq == endian::little) ? 0x4949 : 0x4d4d;
     head.tiff_version = 42;
+    if (endianreq != endian::native)
+        swap_endian(&head.tiff_version);
     // N.B. need to swap_endian head.tiff_diroff  below, once we know the sizes
     append(blob, head);