TikZ/PGF

1. Beautiful, Configurable Drawings
2. Creates PDF Images, Document Class: standalone.
3. Include PDF Image in $\LaTeX$ doc: \includegraphics.
4. For web: pdf2svg/svg2pdf.
5. https://texample.net/tikz/examples/
6. My TikZ Preamble:

\usepackage{xcolor}
\usepackage{graphicx}
\usepackage{ifthen}
\usepackage{xifthen}

%\usepackage{amssymb,amsmath,amsthm}

\usepackage{pgfplots}


\usepackage{pgf,pgffor}


\usepackage{tikz}
\usepackage{tkz-euclide}
%%!
%%! For older versions of package tkz-euclide
%%! you may need uncomment the following line:
%   \usetkzobj{all}
%%!

\usetikzlibrary
    {
      shapes.geometric,
      arrows,
      calc,
      intersections,
      arrows.meta,
      decorations.markings,
      positioning,
      math,
      angles,
      quotes,
      patterns,3d,
      backgrounds,
      fillbetween
    }

\makeatletter
\newcommand{\gettikzxy}[3]{%
  \tikz@scan@one@point\pgfutil@firstofone#1\relax
  \edef#2{\the\pgf@x}%
  \edef#3{\the\pgf@y}%
  \tikzmath{\#2=#2/28.3465;};
  \tikzmath{\#3=#3/28.3465;};
}
\makeatother
\pgfplotsset{compat=1.14}