pgfplot：在包含装饰函数的同时进行填充

Question

我正在尝试在 groupplot 环境中填充特定图的区域。我已经尝试遵循 pgfplot 手册，该手册对 abd 的说明非常清楚，name path但\path[] ...我总是得到同样奇怪的结果（见下图）。由于我使用 x 轴作为填充之间的分界线，因此我开始尝试使用其他东西来检查是否会发生变化。

以下是我的 MWE：

\usepackage{tikz}
\usepackage{pgfplots}
\usepgfplotslibrary{fillbetween}
\usepackage{textcomp}
\pgfplotsset{compat=1.18}
\usepackage{siunitx}
\usepackage{tikzscale}
\usetikzlibrary{pgfplots.groupplots}
\usetikzlibrary{decorations.markings}

\begin{document}

    \begin{tikzpicture}
    
        \begin{groupplot}[
            group style={
                group name = 4L_keywaveform_sim_S6currentstress,
                group size = 1 by 1,
                vertical sep = 15pt
                },
            clip=true,
            enlargelimits=false,
            height = 0.75\textwidth,
            width = \textwidth,
            axis x line = bottom,
            axis y line = left,
            xlabel={$t$},
            xlabel style={align=right, anchor=west, xshift=5.8cm, yshift=0.6cm},
            x axis line style={shorten >=-15pt},
            xmin=0, xmax=12.5,
            ymajorgrids=true, yminorgrids = true, xmajorgrids=true, grid style={dashed},
            set layers,cell picture=true,
            ]
            
            \nextgroupplot[ymin=0, %Position colunm 1 by row 1
                            ymax=15, 
                            ytick align = outside,
                            ytick pos = left,
                            axis y line = left,
                            ylabel = {$y$},
                            legend columns=1,
                            ]
                \addplot[color=blue, name path global = teste1, domain=0:15,
                        postaction={decorate},% ------
                        decoration={markings, % ------
                            mark=between positions 0.05 and 1 step (1/10)*\pgfdecoratedpathlength with {\arrow{Latex}},
                           },                    
                        ]  {x};
                \label{test}; \addlegendentry{$x$};
                \addplot[color=red, name path global = teste2, domain=0:15]  {-3 + x^2}; 
                \path[name path global = teste3] (axis cs:0,5) -- (axis cs:12.5,5);
                \addplot[blue, fill=blue, fill opacity=0.4] fill between[of= teste1 and teste3];
    
        \end{groupplot}    
    \end{tikzpicture}

\end{document}

为了简化目的，MWE 仅包含 1by1 组图。但 n by m 组图仍然存在问题。

编辑/更新：通过进一步调查，似乎装饰参数与填充之间发生了混淆。不过，我不知道原因是什么。

谢谢，

Answer 1

装饰postaction会破坏路径，但它可以与一起使用preaction。您也可以始终使用该选项添加两次情节forget plot。

\documentclass[tikz, border=1cm]{standalone}
\usepackage{pgfplots}
\pgfplotsset{compat=1.18}
\usepgfplotslibrary{fillbetween}
\usetikzlibrary{decorations.markings}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
axis lines=center,
xmin=0, xmax=12.5,
ymin=0, ymax=15,
]
\draw[name path=line] (0,5) -- (12.5,5);
\addplot[
name path=plot, 
blue,
domain=0:12.5,
preaction={decorate},
decoration={markings, mark=between positions 0.05 and 1 step (1/10)*\pgfdecoratedpathlength with {\arrow{latex}}},                    
] {x};
\addplot[fill=blue!40] fill between[of=line and plot];
\end{axis}    
\end{tikzpicture}
\end{document}