Reading plain (untranslated) tag values using API

[sarunasb]

Hi,

Is it possible to retrieve plain (untranslated) EXIF values via exiv2 API, similarly to how it is done with exiv2 -pv ...?

A practical example would be to retrieve Exif.OlympusEq.LensType as 0 0 0 0 0 0 instead of what is output by N_("None").

Thank you!

[clanmills]

Translated simply means "suitable for humans". You can see the value and translated value with the exiv2 command options -Pv and -Pt.

618 rmills@rmillsm1:~/gnu/github/exiv2/0.27-maintenance/src $ exiv2 -K Exif.Image.Orientation ~/Stonehenge.jpg 
Exif.Image.Orientation                       Short       1  top, left
619 rmills@rmillsm1:~/gnu/github/exiv2/0.27-maintenance/src $ exiv2 -Pv -K Exif.Image.Orientation ~/Stonehenge.jpg 
1
620 rmills@rmillsm1:~/gnu/github/exiv2/0.27-maintenance/src $ exiv2 -Pt -K Exif.Image.Orientation ~/Stonehenge.jpg 
top, left
621 rmills@rmillsm1:~/gnu/github/exiv2/0.27-maintenance/src $ 

That output is generated by the code in Print::printMetadatum() in samples/actions.cpp

        if (Params::instance().printItems_ & Params::prValue && md.size() > 0) {
            if (!first)
                std::cout << "  ";
            first = false;
            std::ostringstream os;
            // #1114 - show negative values for SByte
            if (md.typeId() == Exiv2::signedByte) {
                for ( long c = 0 ; c < md.value().count() ; c++ ) {
                    long value = md.value().toLong(c);
                    os << (c?" ":"") << std::dec << (value < 128 ? value : value - 256);
                }
            } else {
                os << std::dec << md.value();
            }
            binaryOutput(os);
        }
        if (Params::instance().printItems_ & Params::prTrans) {
            if (!first)
                std::cout << "  ";
            first = false;
            std::ostringstream os;
            os << std::dec << md.print(&pImage->exifData());
            binaryOutput(os) ;
        }

The command-line option -Pv => Params::prValue and -Pt => Params::prTrans.

So, that code prints the value using os << md.value() and the translated value with os << md.print(&pImage->exifData());

The documentation for md is here: https://exiv2.org/doc/classExiv2_1_1Metadatum.html and includes:

virtual std::string toString () const =0
Return the value as a string.

and

  std::string print (const ExifData *pMetadata=nullptr) const
  Write the interpreted value to a string. More...

[sarunasb]

Thank you very much for the answer.