填充tikz中绘制函数下的区域

Question

对于显示的 MWE：

• 我需要使用“绘图命令”填充 tikz 中绘制的函数下方的区域。但是，使用“绘制命令”中的“填充”选项不会产生任何结果。

• 我有时需要填充地块下方的区域，有时需要填充地块上方的区域。

• 我还可以用垂直线等图案替换填充吗？...

• 此外，有没有办法只填充/孵化此类地块内的某个区域？

\documentclass{article}
\usepackage{amsmath} 
\usepackage{tikz}
\begin{document}
\begin{center}
\begin{tikzpicture}
\draw[help lines,step=0.5](0,0) grid(15,24);
\begin{scope}[shift={(0,6)}]
\draw[thick,color=red,fill=yellow,domain=0:6] plot (\x, {0.1*(5*-1)*(\x*6)/(12)});
\draw[thick,color=red,fill=yellow,domain=6:12] plot (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)});
\end{scope}
\end{tikzpicture}
\end{center}
\end{document}

Answer 1

代码：

\documentclass[tikz,border=12mm]{standalone}

\begin{document}

\begin{tikzpicture}
\draw[help lines,step=0.5](0,0) grid(15,10);
\begin{scope}[shift={(0,6)}]
\fill [yellow] (0,-1.5) -- plot[domain=0:6]  (\x, {0.1*(5*-1)*(\x*6)/(12)});
\draw[thick,color=red,domain=0:6] plot (\x, {0.1*(5*-1)*(\x*6)/(12)});

\fill [yellow] (6,0)-- plot[domain=6:12]  (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)});
\draw[thick,color=red,domain=6:12] plot (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)});
\end{scope}
\end{tikzpicture}

\end{document}

输出：

代码2：

\begin{tikzpicture}
\draw[help lines,step=0.5](0,0) grid(15,10);
\begin{scope}[shift={(0,6)}]
\fill [yellow]  plot[domain=0:6]  (\x, {0.1*(5*-1)*(\x*6)/(12)})--(6,0);
\draw[thick,color=red,domain=0:6] plot (\x, {0.1*(5*-1)*(\x*6)/(12)});

\fill [yellow] (6,0)-- plot[domain=6:12]  (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)});
\draw[thick,color=red,domain=6:12] plot (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)});
\end{scope}
\end{tikzpicture}

输出：

代码3：

\begin{tikzpicture}
\draw[help lines,step=0.5](0,0) grid(15,10);
\begin{scope}[shift={(0,6)}]
\fill [yellow] (0,-1.5) -- plot[domain=0:6]  (\x, {0.1*(5*-1)*(\x*6)/(12)});
\draw[thick,color=red,domain=0:6] plot (\x, {0.1*(5*-1)*(\x*6)/(12)});

\fill [yellow]  plot[domain=6:12]  (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)})--(12,-1.5);
\draw[thick,color=red,domain=6:12] plot (\x, {0.1*(5*-1)*((12-\x)*(6))/(12)});
\end{scope}
\end{tikzpicture}

输出：