Axis configurations not being applied. Some axis with fixed length

Question

The code below best reproduces the issue.

\documentclass[multi=true, crop=true]{standalone}
\usepackage{pgfplots, textcomp}
\standaloneenv{tikzpicture}
\usetikzlibrary{patterns, arrows.meta, decorations.pathreplacing, calc, matrix, positioning, angles, quotes, babel, intersections}

\pgfplotsset{compat=newest, samples=5000,
axis lines=center, axis equal,
xlabel={$x$}, ylabel={$y$},
enlarge x limits=false, enlarge x limits=false}
\begin{documment}
\begin{tikzpicture}[scale=0.75]%183
\xdef\ux{2}
\xdef\uy{1}
\xdef\vx{1}
\xdef\vy{2}
\pgfmathparse{\vy+\uy}
\xdef\sy{\pgfmathresult}
\pgfmathparse{\vx+\ux}
\xdef\sx{\pgfmathresult}
\begin{axis}[xtick=\empty, ytick=\empty, xmin=0,xmax=4, ymin=0, ymax=4,  
extra y ticks={\uy, \vy, \sy}, extra y tick labels={$y_1$, $y_2$, $y_1+y_2$},
extra x ticks={\vx, \ux, \sx}, extra x tick labels={$x_2$, $x_1$, $x_1+x_2$}]
\addplot[-latex] coordinates {(0,0)(\ux,\uy)} node[midway,below]{$\overrightarrow{u}$};
\addplot[-latex] coordinates {(0,0)(\vx,\vy)} node[midway,above]{$\overrightarrow{v}$};
\addplot[dashed] coordinates {(0,\vy)(\vx,\vy)(\vx,0)};
\addplot[dashed] coordinates {(0,\uy)(\ux,\uy)(\ux,0)};
\addplot[-latex] coordinates {(0,0)({\ux+\vx},{\uy+\vy})} node[pos=0.7,above left]{$\overrightarrow{u}+\overrightarrow{v}$};
\addplot[dashed] coordinates {(\ux,\uy)({\ux+\vx},{\uy+\vy})};
\addplot[dashed] coordinates {(\vx,\vy)({\ux+\vx},{\uy+\vy})};
\addplot[dashed] coordinates {(0,{\uy+\vy})({\ux+\vx},{\uy+\vy})({\ux+\vx},0)};
\end{axis}
\end{tikzpicture}
\end{documment}

The x axis should start with 0, but is starting with something else. I tried setting axis lines=center inside the axis environment too, but without effect. At another plot, the fixed length is the y axis, and I don't know why. There are some plots (I belive around 10) with the same issue.

Answer 1

Solution 1 You can just set xmin=0.8. Also replace \begin{documment} and \end{documment} with \begin{document} and \end{document}.

Input

\documentclass[multi=true, crop=true]{standalone}
\usepackage{pgfplots, textcomp}
\standaloneenv{tikzpicture}
\usetikzlibrary{patterns, arrows.meta, decorations.pathreplacing, calc, matrix, positioning, angles, quotes, babel, intersections}

\pgfplotsset{compat=newest, samples=5000,
axis lines=center, axis equal,
xlabel={$x$}, ylabel={$y$},
enlarge x limits=false, enlarge x limits=false}
\begin{document}
\begin{tikzpicture}[scale=0.75]%183
\xdef\ux{2}
\xdef\uy{1}
\xdef\vx{1}
\xdef\vy{2}
\pgfmathparse{\vy+\uy}
\xdef\sy{\pgfmathresult}
\pgfmathparse{\vx+\ux}
\xdef\sx{\pgfmathresult}
\begin{axis}[xtick=\empty, ytick=\empty, xmin=0.8,xmax=4, ymin=0, ymax=4,  
extra y ticks={\uy, \vy, \sy}, extra y tick labels={$y_1$, $y_2$, $y_1+y_2$},
extra x ticks={\vx, \ux, \sx}, extra x tick labels={$x_2$, $x_1$, $x_1+x_2$}]
\addplot[-latex] coordinates {(0,0)(\ux,\uy)} node[midway,below]{$\overrightarrow{u}$};
\addplot[-latex] coordinates {(0,0)(\vx,\vy)} node[midway,above]{$\overrightarrow{v}$};
\addplot[dashed] coordinates {(0,\vy)(\vx,\vy)(\vx,0)};
\addplot[dashed] coordinates {(0,\uy)(\ux,\uy)(\ux,0)};
\addplot[-latex] coordinates {(0,0)({\ux+\vx},{\uy+\vy})} node[pos=0.7,above left]{$\overrightarrow{u}+\overrightarrow{v}$};
\addplot[dashed] coordinates {(\ux,\uy)({\ux+\vx},{\uy+\vy})};
\addplot[dashed] coordinates {(\vx,\vy)({\ux+\vx},{\uy+\vy})};
\addplot[dashed] coordinates {(0,{\uy+\vy})({\ux+\vx},{\uy+\vy})({\ux+\vx},0)};
\end{axis}
\end{tikzpicture}
\end{document}

Output

Solution 2: The real problem here is caused by the fact that you demand the axis to be equal. So you can also just remove axis equal, instead of changing the value of xmin.