pngexif: Import pngexifinfo as an externally-contributed project
We used this experimental project in the development of the PNG-EXIF
("eXIf") specification, back in 2017. The project evolved together
with the draft specification, which was finalized on 2017-Jun-15 and
approved by the PNG Group on 2017-Jul-13.
The EXIF specification, outside of the scope of PNG and libpng, is
quite complex. The libpng implementation cannot grow too much beyond
performing basic integrity checks on top of serialization. In order
to create and manipulate PNG-EXIF image files, the use of external
libraries and tools such as ExifTool is necessary.
Now, with the addition of contrib/pngexif to the libpng repository,
offline tasks like metadata inspection and linting can be performed
without importing external dependencies.
10 files changed
