Exiv2

Needs a new PngImage class to parse (decode and encode) metadata from/into PNG images. Among the metadata types that can be stored in PNG images are Exif, IPTC and XMP.

Additional information:

From Gilles Caulier:

If you is interressed to make a simple PNG parser in Exiv2 (My dream (:=))),
just take a look in KDE API (KFileMetaInfo class). This is a simple class to
extract metadata (not too powerfull than Exiv2) from image/audio/video file.

About PNG KFileMetaInfo use a plugin to parse in read only PNG file. The code
is simple and do not use libPNG :

http://websvn.kde.org/trunk/KDE/kdegraphics/kfile-plugins/png/kfile_png.cpp?rev=506839&view=auto

If you want some help to clarify Qt/KDElib API, let's me hear...

About Raw profile embedded into PNG file by IM, take a look here :

http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/PNG.html#TextualData

look like IM can provide also XMP raw profile !!! For the future of Exiv2
(:=)))...

From http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/PNG.html#TextualData:

Metadata is stored in PNG TextualData format, which allows aribrary tag names to be used. The information for the TextualData tags may be stored as tEXt, zTXt or iTXt chunks in the PNG image.