平衡填充和绘制之间的不透明度

Question

可能我的标题不太有用。我的问题是我尝试使用以下代码在某些顶点上“绘制”超边：

\usepackage{tikz}

\tikzstyle{vertex} = [fill, shape=circle, opacity=1, node distance=80pt]
\tikzstyle{hyperedge} = [fill, opacity=1, cap=round, join=round, line width=60pt]
\tikzstyle{elabel} = [fill, shape=circle, node distance=30pt]

\pgfdeclarelayer{background}
\pgfsetlayers{background,main}

\begin{document}

\begin{tikzpicture}
\node[vertex,label=above left:$v_1$] (v1) {};
\node[vertex,right of=v1,label=above right:$v_2$] (v2) {};
\node[vertex,below of=v1,label=below left:$v_3$] (v3) {};
\node[vertex,right of=v3,label=below right:$v_4$] (v4) {};

\begin{pgfonlayer}{background}

\draw[hyperedge, color=yellow] (v1.center)--(v2.center)--(v3.center)--cycle;
\draw[hyperedge, color=pink, line width=45pt] (v2.center)--(v3.center)--(v4.center)--cycle;

\end{pgfonlayer}

\node[elabel,color=yellow,label=right:$C_1$]  (e1) at (-3,0) {};
\node[elabel,below of=e1,color=pink,label=right:$C_2$]  (e2) {};
\end{tikzpicture}

\end{document}

这将产生以下内容：

效果还不错，但是交叉点不太明显。如果我将超边的不透明度设置为 0.5：

\tikzstyle{hyperedge} = [fill, opacity=0.5, cap=round, join=round, line width=60pt]

我得到：

这里的交叉点更加明显，但由于“填充”和循环的“线条”也相交，受影响的部分变得更加不透明（？）。有没有办法解决这种情况？也许只在循环的一侧绘制线条，避免与填充相交，但这可能吗？

Answer 1

我认为正确的解决方案是这样的。我在手册中找到了它：

从“超边”样式中移除不透明度：

\tikzstyle{hyperedge} = [fill, cap=round, join=round, line width=60pt]

将每条边放入其自己的透明度组中：

\begin{scope}[transparency group,  opacity=0.5]
\draw[hyperedge, color=yellow] (v1.center)--(v2.center)--(v3.center)--cycle;
\end{scope}


\begin{scope}[transparency group,  opacity=0.5]
\draw[hyperedge, color=pink, line width=45pt] (v2.center)--(v3.center)--(v4.center)--cycle;
\end{scope}

谢谢大家的答案！

Answer 2

肮脏的黑客：

如果特定形状的线条稍微宽一些，则无需担心任何填充颜色，因为线条会填充整个形状：

\documentclass{standalone}

\usepackage{tikz}

\tikzset{
  vertex/.style={fill, shape=circle, opacity=1, node distance=80pt},
  hyperedgeline/.style={opacity=0.5, cap=round, join=round,line width=60pt},
  elabel/.style={fill, shape=circle, node distance=30pt}
}

\pgfdeclarelayer{background}
\pgfsetlayers{background,main}


\begin{document}

\begin{tikzpicture}
\node[vertex,label=above left:$v_1$] (v1) {};
\node[vertex,right of=v1,label=above right:$v_2$] (v2) {};
\node[vertex,below of=v1,label=below left:$v_3$] (v3) {};
\node[vertex,right of=v3,label=below right:$v_4$] (v4) {};

\begin{pgfonlayer}{background}

\draw[hyperedgeline, color=yellow] (v1.center)--(v2.center)--(v3.center)--cycle;
\draw[hyperedgeline, color=pink, line width=47pt] (v2.center)--(v3.center)--(v4.center)--cycle;

\end{pgfonlayer}

\node[elabel,color=yellow,label=right:$C_1$]  (e1) at (-3,0) {};
\node[elabel,below of=e1,color=pink,label=right:$C_2$]  (e2) {};
\end{tikzpicture}

\end{document}

Answer 3

使用fill opacity。

\documentclass{article}
\usepackage{tikz}

\tikzstyle{vertex} = [fill, shape=circle, opacity=1, node distance=80pt]
\tikzstyle{hyperedge} = [opacity=0.5,fill opacity=1, cap=round, join=round, line width=60pt]
\tikzstyle{elabel} = [fill, shape=circle, node distance=30pt]

\pgfdeclarelayer{background}
\pgfsetlayers{background,main}

\begin{document}

\begin{tikzpicture}
\node[vertex,label=above left:$v_1$] (v1) {};
\node[vertex,right of=v1,label=above right:$v_2$] (v2) {};
\node[vertex,below of=v1,label=below left:$v_3$] (v3) {};
\node[vertex,right of=v3,label=below right:$v_4$] (v4) {};

\begin{pgfonlayer}{background}

\draw[hyperedge, color=yellow] (v1.center)--(v2.center)--(v3.center)--cycle;
\draw[hyperedge, color=pink, line width=45pt] (v2.center)--(v3.center)--(v4.center)--cycle;

\end{pgfonlayer}

\node[elabel,color=yellow,label=right:$C_1$]  (e1) at (-3,0) {};
\node[elabel,below of=e1,color=pink,label=right:$C_2$]  (e2) {};
\end{tikzpicture}

\end{document}