pgfplot 图例中的线条颜色错误

Question

我如何确保图例中穿过棕色方块的线（更清晰，在 R^2 处）是绿色，就像图表的直线一样？

这是我的最小工作示例：

\documentclass[12pt]{article}
\usepackage{pgfplots}

\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}
  \begin{axis}[
  legend pos=outer north east,
  legend cell align={left},
 grid,
    grid style={line width=.1pt, draw=gray!0},
  ymin=0,ymax=14,
  xmax=14,xmin=0,
  xtick={2,4,6,8,10,12},
  ytick={2,4,6,8,10,12},
  extra x ticks={0},
  extra y ticks={0},
            width=7cm,
            height=7cm,
  axis lines = middle,
  set layers,
  x label style={at={(1,0)},right},
  y label style={at={(0,1)},above},
  style={thick}
               ]              
        \addplot [green,smooth,thick,domain=0:12] {1.0016*x};
        \addlegendentry{$f(x) = 1.0016x$};
        \addplot[mark=square*,brown] coordinates {(0.1384,0.1338)};
        \addplot[mark=square*,brown] coordinates {(1.288,1.278)};
        \addplot[mark=square*,brown] coordinates {(11.65,11.67)};
        \addlegendentry{$R^2 = 1.000$};
    \end{axis};
\end{tikzpicture}
\end{figure}

\end{document}

Answer 1

一种选择是提前单独提供图例条目和相应的图像，使用图表开头的legend entries轴选项和命令列表。这样您就可以分别指定线条颜色和标记颜色。\addlegendimage

梅威瑟：

\documentclass[12pt]{article}
\usepackage{pgfplots}

\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}
  \begin{axis}[
  legend pos=outer north east,
  legend cell align={left},
 grid,
    grid style={line width=.1pt, draw=gray!0},
  ymin=0,ymax=14,
  xmax=14,xmin=0,
  xtick={2,4,6,8,10,12},
  ytick={2,4,6,8,10,12},
  extra x ticks={0},
  extra y ticks={0},
            width=7cm,
            height=7cm,
  axis lines = middle,
  set layers,
  x label style={at={(1,0)},right},
  y label style={at={(0,1)},above},
  style={thick},
  legend entries={$f(x) = 1.0016x$, $R^2 = 1.000$}
               ]
  \addlegendimage{no markers, green, thick}
  \addlegendimage{green, thick, mark=square*, mark options={solid,draw=brown,fill=brown}}
        \addplot [green,smooth,thick,domain=0:12] {1.0016*x};
        \addplot[mark=square*,brown] coordinates {(0.1384,0.1338)};
        \addplot[mark=square*,brown] coordinates {(1.288,1.278)};
        \addplot[mark=square*,brown] coordinates {(11.65,11.67)};
    \end{axis};
\end{tikzpicture}
\end{figure}

\end{document}

结果：

请注意，从概念上讲，在图例中添加 R² 框而不添加线可能更正确。这可以使用您的原始代码来完成，但only marks在命令中指定\addplot：

\addplot[only marks, mark=square*,brown] coordinates {(0.1384,0.1338)};
\addplot[only marks, mark=square*,brown] coordinates {(1.288,1.278)};
\addplot[only marks, mark=square*,brown] coordinates {(11.65,11.67)};
\addlegendentry{$R^2 = 1.000$};

这也允许您一次提供所有坐标，而无需在它们之间画一条线：

\addplot[only marks, mark=square*,brown] coordinates {(0.1384,0.1338) (1.288,1.278) (11.65,11.67)};