Elimine o espaço entre as figuras tikz

Question

O seguinte MWE

\documentclass{article}
\usepackage{tikz}
\begin{document}
\noindent{}\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}\\
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}
\end{document}

produz

Eu sei que posso eliminar o espaço em branco com algo como:

\documentclass{article}
\usepackage{tikz}
\begin{document}
\noindent{}\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}\hspace*{-0.3em}
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}\\[-1pt]
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}\hspace*{-0.3em}
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}
\end{document}

mas isso exige que eu ajuste manualmente o espaçamento e parece sujeito a erros. Existe uma maneira automática de eliminar o espaço em branco (horizontal e vertical) entre as figuras?

Answer 1

Você pode usar um tabular, com parâmetros definidos corretamente:

\documentclass{article}
\usepackage{tikz}

\newenvironment{pics}
 {\par\raggedright % maybe \centering
  \setlength\tabcolsep{0pt}\renewcommand{\arraystretch}{0}%
  \begin{tabular}{*{10}c}}
 {\end{tabular}\par}

\begin{document}

\begin{pics}
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} \\
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}
\end{pics}

\bigskip

\begin{pics}
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} \\
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture} &
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}
\end{pics}

\end{document}

Answer 2

As lacunas horizontais são explicadas pelo método de AndrewComente: Espaços por fim de linha entre os ambientes.

Como as imagens são maiores que o salto da linha de base, o TeX usa o registro \lineskippara separar as caixas na direção vertical:

\documentclass{article}
\usepackage{tikz}
\begin{document}
\noindent
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}%
\begin{tikzpicture}\fill [red] (0,0) rectangle(1,1);\end{tikzpicture}%
\\[-\lineskip]
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}%
\begin{tikzpicture}\fill [red] (0,0) rectangle (1,1);\end{tikzpicture}%
\end{document}