Automatically hide border if fill color is "none" in TikZ picture

Question

I have a defined command as shown in the MWE as follows:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}

\newcommand\shapes[3]
{\begin{tikzpicture}
\draw[fill=#1] (0,0) rectangle (1,1);
\draw[fill=#2] (0,2.5) circle (0.5);
\draw[fill=#3] (3,2) ellipse (1 and 0.75);
\end{tikzpicture}}

\begin{document}

\shapes{yellow}{green!50}{red!50}

\end{document}

Sometimes I don't want to color a particular shape in, which is when I set the fill color to none, like so: \shapes{yellow}{none}{none}.

However, when I do this, I don't want the border to remain (in other words, I want the shape to disappear completely if I specify the color as none – I don't want the border to remain.

Is there a good way to way to automatically make the border color none (or perhaps make the \draw command a \fill command, if the fill color is none (which would get rid of the border)?

Answer 1

You could use the draw key.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}

\newcommand\shapes[3]
{\begin{tikzpicture}
\draw[draw=#1,fill=#1] (0,0) rectangle (1,1);
\draw[draw=#2,fill=#2] (0,2.5) circle (0.5);
\draw[draw=#3,fill=#3] (3,2) ellipse (1 and 0.75);
\end{tikzpicture}}

\begin{document}

\shapes{yellow}{green!50}{red!50}
\shapes{yellow}{none}{none}

\end{document}

---

Update: This version keeps the border.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usepackage{ifthen}

\newcommand\shapes[3]
{\begin{tikzpicture}
\ifthenelse{\equal{none}{#1}}{\def\mycol{#1}}{\def\mycol{black}}
\draw[draw=\mycol,fill=#1] (0,0) rectangle (1,1);
\ifthenelse{\equal{none}{#2}}{\def\mycol{#2}}{\def\mycol{black}}
\draw[draw=\mycol,fill=#2] (0,2.5) circle (0.5);
\ifthenelse{\equal{none}{#3}}{\def\mycol{#3}}{\def\mycol{black}}
\draw[draw=\mycol,fill=#3] (3,2) ellipse (1 and 0.75);
\end{tikzpicture}}

\begin{document}

\shapes{yellow}{green!50}{red!50}
\shapes{yellow}{none}{none}

\end{document}