add metadata to f3d::image

[snoyer]

Add support for metadata key,value pairs on f3d::image objects.

Saving and loading is currently only implemented for PNG format. It may be technically possible for other formats (eg. JPEG using Exif data) assuming VTK supports it.

Metadata would be used by future features to embed data in F3D's render, such as camera parameters, rendering options, ...

[github-actions]

You are modifying libf3d public API! ⚠️Please update bindings accordingly⚠️!
You can find them in their respective directories: python, java, webassembly.

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (3f8eb1d) 96.59% compared to head (b5dedd4) 96.57%.
Report is 1 commits behind head on master.

Files	Patch %	Lines
library/src/image.cxx	97.91%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1273      +/-   ##
==========================================
- Coverage   96.59%   96.57%   -0.02%     
==========================================
  Files         138      138              
  Lines        8446     8494      +48     
==========================================
+ Hits         8158     8203      +45     
- Misses        288      291       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[snoyer]

library/src/image.cxx:56:23: style: Variable 'key' is not assigned a value. [unassignedVariable]
    for (const auto& [key, value] : this->Metadata)
                      ^

supposedly a fixed bug https://trac.cppcheck.net/ticket/10368

[mwestphal]

this approach looks fine to me. Wdyt @Meakk ?

[mwestphal]

There was an issue that required rewriting history. Please cherry pick your commits on f3d-app/f3d master.

[snoyer]

re-opening for no reason, nothing happened, there was no git accident, at all, ever