背景颜色混合

Question 1

很难知道你到底想要什么效果，说实话我觉得混合模式是一种黑魔法……但这有一个想法。

有几件事您需要修复。

首先，将背景层放在混合透明度范围内是行不通的。因此，将其移到外面，这样透明度范围内就只有三个矩形了。

其次，使用粗线，虽然是一种获得更大边框的巧妙方法，但是会填满混合，因为您会在填充顶部绘制线条。

第三，示例维恩图中选择的混合模式对于按该顺序绘制的颜色效果很好。但对于您选择的颜色效果就不太好了。如果您最后绘制黄色矩形，看起来就没问题。或者您可能会发现混合模式multiply也适合您所追求的效果。

以下是我对混合的建议：

  \begin{pgfonlayer}{background}
    \begin{scope}[
        blend group = soft light,
        rounded corners=10pt,
        nw/.style={xshift=-10pt,yshift=10pt},
        se/.style={xshift=10pt, yshift=-10pt},
        snw/.style={xshift=-5pt,yshift=5pt},
        sse/.style={xshift=5pt, yshift=-5pt}]
      \fill [green!20!white]
        ([snw]{whatever3.north -| ctis.west}) rectangle
        ([sse]{ta.south -| ta.east});
      \fill [red!15!white]
        ([snw]{whatever4.north -| and2.west)} rectangle
        ([sse]{a.south -| cvr.east});
      \fill [yellow!20!white]
        ([nw]{ss.north -| ctis.west}) rectangle
        ([se]{whatever1.south -| cvr.east});
    \end{scope}
  \end{pgfonlayer}

得出：

另一种方法是使用multiply混合模式，其效果如下：

或者可能只是使用普通的透明度，我发现这比混合更直观：

  \begin{pgfonlayer}{background}
    \begin{scope}[
        rounded corners=10pt,
        nw/.style={xshift=-10pt,yshift=10pt},
        se/.style={xshift=10pt, yshift=-10pt},
        snw/.style={xshift=-5pt,yshift=5pt},
        sse/.style={xshift=5pt, yshift=-5pt}]
      \fill [yellow!20!white]
        ([nw]{ss.north -| ctis.west}) rectangle
        ([se]{whatever1.south -| cvr.east});
      \fill [green, opacity=0.2]
        ([snw]{whatever3.north -| ctis.west}) rectangle
        ([sse]{ta.south -| ta.east});
      \fill [red, opacity=0.15]
        ([snw]{whatever4.north -| and2.west)} rectangle
        ([sse]{a.south -| cvr.east});
    \end{scope}
  \end{pgfonlayer}

以下是第一个选项的完整 MWE：

\documentclass[tikz]{standalone}
\usepackage{tikz}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usetikzlibrary{arrows,petri,backgrounds}
\tikzset{>=stealth',every on chain/.append style={join}, every join/.style={->}}
\begin{document}
\begin{tikzpicture}[thick,auto,node distance=58pt]
  \tikzstyle{n}=[circle,draw=blue!75,fill=blue!20,minimum size=10pt,
    inner sep=0pt]
  \tikzstyle{pil}=[->,thick,shorten <=2pt,shorten >=2pt]
  \node [n] (css) [label=above:$c$] {};
  \node [n] (ss) [label=left:$\text{SelectedStudy}(\texttt{s}_i)$,
    below of=css, yshift=20pt,tokens=1] {};
  \node [n] (and1) [label=above left:$\texttt{AND}$,
    below left of=ss, tokens=1] {};
  \node [n] (and2) [label=above right:$\texttt{AND}$, below right of=ss, tokens=1] {};
  \node [n] (tis) [label=below:{$\text{TermInStudy}(\texttt{t}_j, \texttt{s}_i)$}, left of=and1, tokens=1] {};
  \node [n] (vr) [label=below:{$\text{VoxelReported}(\texttt{v}_k, \texttt{s}_i)$}, right of=and2, tokens=1] {};
  \node [n] (ctis) [label=above:$c_{ji}$, left of=tis] {};
  \node [n] (cvr) [label=above:$c_{ki}$, right of=vr] {};
  \node [n] (ta) [label=left:$\text{TermAssociation}(\texttt{t}_j)$, below of=and1] {};
  \node [n] (a) [label=right:$\text{Activation}(\texttt{v}_k)$, below of=and2] {};

  \node (whatever1) [below of=cvr,yshift=30pt] {};
  \node (whatever2) [above of=cvr,yshift=-13pt,xshift=-5pt] {$i \in N$};
  \node (whatever3) [above of=ctis,yshift=-45pt] {};
  \node (whatever4) [above of=cvr,yshift=-45pt] {};
  \node (whatever5) [right of=a,xshift=50pt] {$k \in K$};
  \node (whatever6) [left of=ta,xshift=-50pt] {$j \in M$};

  \node [n] (whatever7) [opacity=0.6, left of=css,xshift=-80pt, tokens=1,
    label=right:{\scriptsize deterministic CPD}] {};

  \path[pil] (css) edge (ss);
  \path[pil] (ss) edge (and1);
  \path[pil] (ss) edge (and2);
  \path[pil] (ctis) edge (tis);
  \path[pil] (tis) edge (and1);
  \path[pil] (cvr) edge (vr);
  \path[pil] (vr) edge (and2);
  \path[pil] (and1) edge (ta);
  \path[pil] (and2) edge (a);

  \begin{pgfonlayer}{background}
    \begin{scope}[
        blend group = soft light,
        rounded corners=10pt,
        nw/.style={xshift=-10pt,yshift=10pt},
        se/.style={xshift=10pt, yshift=-10pt},
        snw/.style={xshift=-5pt,yshift=5pt},
        sse/.style={xshift=5pt, yshift=-5pt}]
      \fill [green!20!white]
        ([snw]{whatever3.north -| ctis.west}) rectangle
        ([sse]{ta.south -| ta.east});
      \fill [red!15!white]
        ([snw]{whatever4.north -| and2.west)} rectangle
        ([sse]{a.south -| cvr.east});
      \fill [yellow!20!white]
        ([nw]{ss.north -| ctis.west}) rectangle
        ([se]{whatever1.south -| cvr.east});
    \end{scope}
  \end{pgfonlayer}
\end{tikzpicture}

\end{document}

Answer