Add function to convert single channel image data to RGB image

[iche033]

🎉 New feature

Summary

Used by gazebosim/gz-gui#212 and gazebosim/gz-launch#112

Added a generic helper function for converting single channel image data, e.g. thermal and depth images, to an RGB image. This is intended to be used for visualization. Optional arguments can be specified to tweak the visualization.

Test it

The corresponding PRs in ign gui updates the Image Display to use this new function: gazebosim/gz-gui#212

You can test this together with that PR by running the sensors_demo.sdf world to see the visualization in Image Display

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge

[codecov]

Codecov Report

Merging #205 (90eba51) into ign-common3 (cdfbe87) will increase coverage by 0.12%.
The diff coverage is 97.05%.

@@               Coverage Diff               @@
##           ign-common3     #205      +/-   ##
===============================================
+ Coverage        75.08%   75.20%   +0.12%     
===============================================
  Files               72       73       +1     
  Lines            10273    10307      +34     
===============================================
+ Hits              7713     7751      +38     
+ Misses            2560     2556       -4     

Impacted Files	Coverage Δ
graphics/include/ignition/common/Image.hh	97.05% <97.05%> (ø)
graphics/src/Image.cc	67.08% <0.00%> (+2.08%)	⬆️

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[chapulina]

Windows is not happy about these isinf calls with uint8_t:

Compiler error

C:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt\corecrt_math.h(409): error C2668: 'fpclassify': ambiguous call to overloaded function
C:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt\corecrt_math.h(300): note: could be 'int fpclassify(long double) noexcept'
C:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt\corecrt_math.h(295): note: or       'int fpclassify(double) noexcept'
C:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt\corecrt_math.h(290): note: or       'int fpclassify(float) noexcept'
C:\Program Files (x86)\Windows Kits\10\include\10.0.18362.0\ucrt\corecrt_math.h(409): note: while trying to match the argument list '(_Ty)'
        with
        [
            _Ty=uint8_t
        ]
C:\Jenkins\workspace\ignition_common-ci-pr_any-windows7-amd64\ws\ign-common\graphics\include\ignition/common/Image.hh(226): note: see reference to function template instantiation 'bool isinf<T>(_Ty) noexcept' being compiled
        with
        [
            T=uint8_t,
            _Ty=uint8_t
        ]
C:\Jenkins\workspace\ignition_common-ci-pr_any-windows7-amd64\ws\ign-common\graphics\src\Image_TEST.cc(351): note: see reference to function template instantiation 'void ignition::common::Image::ConvertToRGBImage<uint8_t>(const void *,unsigned int,unsigned int,ignition::common::Image &,T,T,bool)' being compiled
        with
        [
            T=uint8_t
        ]
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.24.28314\include\xstring(1739): note: see reference to class template instantiation 'std::basic_string_view<char,std::char_traits<char>>' being compiled

[mjcarroll]

An approach to remove new/delete as well as the raw pointers: #206

[mjcarroll]

LGTM