Installing from source on MacOS

Tested on Catalina 10.15.4. First some stuff from a package manager, here using Homebrew:

brew install imagemagick openssl cmake

You will also need Python, perhaps:

brew install python3

You will also need latex. Here is one approach:

brew install basictex
eval "$(/usr/libexec/path_helper)"
sudo tlmgr update --self
sudo tlmgr install latexmk dvipng preview exam preprint

or maybe brew install mactex-no-gui or perhaps via some other UI means.

At this point pip install plom (or pip install --user . from inside the Plom source tree) should pull in the remaining dependencies.