包括 TikZ 文件：键 '/tikz/cap' 需要一个值

Question 1

正如我在评论中提到的，TikZ 不允许使用图片作为节点的选项。如果我理解正确的话，您的问题可以通过使用标题为的小图片来解决pic。它们在 TikZ v3.0 和最新版本手册的“18 张图片：路径上的小图片”部分中有描述（在最新版本 3.0.1a 中，它在第 251 页上显示）。

将您设计的图像设计成小图片并在任何文档中将其调用为“\pic {pic 名称}”；
设计的图片存储在 \tikzset{...} 中并将其存储在私有样式包中，例如“my_TikZ_presets”，LaTeX 必须知道这一点（即：将其存储在本地树中的某个位置并更新 LaTeX 文件名数据库；
在文档中，如果您喜欢使用这些图片，则需要加载此样式，并在 TikZ 图片中设置使用的选项tikzset（参见下面的代码）

下面是 MWE，它演示了上述内容。

\documentclass{article}
    \usepackage[svgnames]{xcolor}
    \usepackage{tikz}
\usetikzlibrary{decorations.markings,positioning,shapes.geometric}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    \tikzset{PIC/.style = {%this you can store for example as 
                           % my_TikZ-presets.style somewhere, 
                           % where (La)TeX looking for yours packages
                           % (not in main tree)
                           % here you can collect all styles, which 
                           % you use in yours TikZ pictures
% small picture bell
        bell/.pic = {%path [use as bounding box] (-2,-2) rectangle (2,2); do really need them?
\draw [in= 90,out=180]  (0,0.75) coordinate (-top)  to 
                        (-0.5,0) coordinate (-bottom left);
\draw [in= 90,out=  0]  (0,0.75) to 
                        (0.5, 0) coordinate (-bottom right);
\draw [in=270,out=-90, looseness=0.75] (-0.5,0) to (+0.5,0);
                    }%
                        },% end of bell style
% for nodes with rectangular shape
       box/.style = {draw, line width=1mm, inner sep=1mm,
                     minimum width = 44mm, minimum height=33mm,
                     font=\itshape, align=left},
% for shortening lines on the both sides                    
shorten <>/.style = {shorten < = #1, shorten > = #1},
% etc 
             }% end of tikzset
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% \endinput

\usepackage[graphics,tightpage,active]{preview}
\PreviewEnvironment{tikzpicture}

    \begin{document}
\begin{tikzpicture}[PIC]
% demo for connecting small pictures width line
\pic[red]   at (0,0) (A)    {bell};
\pic[blue]  at (3,0) (B)    {bell};
\draw[dotted, ultra thick,shorten <>=2mm]  (A-bottom right) -- (B-bottom left);
% demo for use it as stamp on letter envelope
\node[box,below right] (C) at (-0.75,-0.5) {To my\\ dearest\\ Clementine};
\pic[below left=of C.north east] (D) {bell};
\end{tikzpicture}
    \end{document}

在上述 MWE 的设计中，我只部分遵循了您的设计。我允许自己在图片设计方面有一定的自由度 :-)。在 MWE 中，只考虑与其相关的定义和包。此 MWE 提供：

Answer

正如我在评论中提到的，TikZ 不允许使用图片作为节点的选项。如果我理解正确的话，您的问题可以通过使用标题为的小图片来解决pic。它们在 TikZ v3.0 和最新版本手册的“18 张图片：路径上的小图片”部分中有描述（在最新版本 3.0.1a 中，它在第 251 页上显示）。

将您设计的图像设计成小图片并在任何文档中将其调用为“\pic {pic 名称}”；
设计的图片存储在 \tikzset{...} 中并将其存储在私有样式包中，例如“my_TikZ_presets”，LaTeX 必须知道这一点（即：将其存储在本地树中的某个位置并更新 LaTeX 文件名数据库；
在文档中，如果您喜欢使用这些图片，则需要加载此样式，并在 TikZ 图片中设置使用的选项tikzset（参见下面的代码）

下面是 MWE，它演示了上述内容。

\documentclass{article}
    \usepackage[svgnames]{xcolor}
    \usepackage{tikz}
\usetikzlibrary{decorations.markings,positioning,shapes.geometric}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    \tikzset{PIC/.style = {%this you can store for example as 
                           % my_TikZ-presets.style somewhere, 
                           % where (La)TeX looking for yours packages
                           % (not in main tree)
                           % here you can collect all styles, which 
                           % you use in yours TikZ pictures
% small picture bell
        bell/.pic = {%path [use as bounding box] (-2,-2) rectangle (2,2); do really need them?
\draw [in= 90,out=180]  (0,0.75) coordinate (-top)  to 
                        (-0.5,0) coordinate (-bottom left);
\draw [in= 90,out=  0]  (0,0.75) to 
                        (0.5, 0) coordinate (-bottom right);
\draw [in=270,out=-90, looseness=0.75] (-0.5,0) to (+0.5,0);
                    }%
                        },% end of bell style
% for nodes with rectangular shape
       box/.style = {draw, line width=1mm, inner sep=1mm,
                     minimum width = 44mm, minimum height=33mm,
                     font=\itshape, align=left},
% for shortening lines on the both sides                    
shorten <>/.style = {shorten < = #1, shorten > = #1},
% etc 
             }% end of tikzset
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% \endinput

\usepackage[graphics,tightpage,active]{preview}
\PreviewEnvironment{tikzpicture}

    \begin{document}
\begin{tikzpicture}[PIC]
% demo for connecting small pictures width line
\pic[red]   at (0,0) (A)    {bell};
\pic[blue]  at (3,0) (B)    {bell};
\draw[dotted, ultra thick,shorten <>=2mm]  (A-bottom right) -- (B-bottom left);
% demo for use it as stamp on letter envelope
\node[box,below right] (C) at (-0.75,-0.5) {To my\\ dearest\\ Clementine};
\pic[below left=of C.north east] (D) {bell};
\end{tikzpicture}
    \end{document}

在上述 MWE 的设计中，我只部分遵循了您的设计。我允许自己在图片设计方面有一定的自由度 :-)。在 MWE 中，只考虑与其相关的定义和包。此 MWE 提供：

Question 2

这与Zarko 的回答。我还使用了pic，并且按照 Zarko 的做法，我将其称为bell。

我要做的是创建一个小型的 TikZ 库，当您希望在图片中使用此类功能时，可以将其与其他库一起加载。

我不完全清楚不同层的用途是什么，因此我以特定的方式详细阐述它，希望您能够看到如何根据自己的需要修改代码。

首先，库代码。我建议将其保存为tikzlibrarybell.code.tex。<TEXMFHOME>/tex/generic/pgf/这<TEXMFHOME>是您的个人texmf树。在 TeX Live 中，kpsewhich -var TEXMFHOME将为您提供路径。但是，如果您只想将其用于一张图片，则可以将其保存在您的工作目录中。当您说时，特定的文件名允许 TikZ 找到它\usetikzlibrary{bell}。

如果我更好地理解了键值对，这段代码无疑会得到显著改善。这是我目前的努力和我目前的理解的成果。

请注意，此处的使用/bell可防止与标准键或其他库中的键发生冲突。例如，我使用的是/bell/cap而不是普通的cap，因此此处不会妨碍行尾的使用cap。此代码中的使用cap严格限于/bell键路径。

% tikzlibrarybell.code.tex
\ProvidesFile{tikzlibrarybell.code.tex}
\pgfdeclarelayer{bell edge layer}
\pgfdeclarelayer{bell node layer}
\pgfsetlayers{bell edge layer,bell node layer,main}
\tikzset{% modified from code at tex/generic/pgf/frontendlayer/tikz/libraries/tikzlibrarybackgrounds.code.tex
  on bell edge layer/.style={%
    execute at begin scope={%
      \pgfonlayer{bell edge layer}%
      \let\tikz@options=\pgfutil@empty%
      \tikzset{every on bell edge layer/.try,#1}%
      \tikz@options%
    },
    execute at end scope={\endpgfonlayer}
  },
  on bell node layer/.style={%
    execute at begin scope={%
      \pgfonlayer{bell node layer}%
      \let\tikz@options=\pgfutil@empty%
      \tikzset{every on bell node layer/.try,#1}%
      \tikz@options%
    },
    execute at end scope={\endpgfonlayer}
  },
  pics/bell/.style={%
    code={%
      \tikzset{%
        /bell/.cd,
        #1,
        /tikz/.cd,
      }%
      \path [use as bounding box] (-2,-2) rectangle (2,2);
      \begin{scope}[on bell node layer]
        \node [pic actions, /bell/node style] (a) at (0, 0.75) {\bell@top@node};
        \node [pic actions, /bell/node style] (b) at (-0.5, 0) {\bell@left@node};
        \node [pic actions, /bell/node style] (c) at (0.5, 0) {\bell@right@node};
      \end{scope}
      \begin{scope}[on bell edge layer]
        \path [pic actions, /bell/cap style] (c.center) [in=0, out=90] to (a.center) [in=90, out=180] to (b.center) [in=270, out=-90, looseness=0.75]  to (c.center);
      \end{scope}
    }%
  },
  /bell/.search also={/tikz},
  /bell/.cd,
  top/.store in=\bell@top@node,
  left/.store in=\bell@left@node,
  right/.store in=\bell@right@node,
  % this cannot be the right way to do this!!!
  cap/.code={\tikzset{/bell/cap style/.style={/tikz/.cd, #1}}},
  nodes/.code={\tikzset{/bell/node style/.style={/tikz/.cd, #1}}},
  top=,
  left=,
  right=,
  cap style/.style={draw},
  node style/.style=,
}
\endinput

这定义了一个带有一个可选参数的pic调用bell。如果指定，参数应该是铃声的选项。除了标准 TikZ 选项外，您还可以使用

cap={<style for cap itself>}
nodes={<style for nodes, if any>}
top={<text for node at top>}
left={<text for node at bottom left>}
right={<text for node at bottom right>}

默认情况下，形状只是简单绘制，节点都是空的，没有任何样式。

给定这个库，我们可以bell pic按照以下方式创建一行：

\documentclass[tikz,border=10pt]{standalone}
\usetikzlibrary{shapes.geometric,bell}
\begin{document}
\begin{tikzpicture}
  \pic {bell};
  \pic at (2,0) {bell={%
      nodes={fill opacity=.75, text=blue, text opacity=1, inner color=blue!10, outer color=blue!30, font=\sffamily, inner sep=0pt, shape=ellipse},
      cap={draw=blue!50!black, ball color=blue!50, thick},
      top={top},
      left={left},
      right={right},
    }};
  \pic at (4,0) {bell={%
      nodes={text=red, draw=red, thick, fill=white, font=\sffamily, inner sep=1pt, shape=circle},
      cap={draw=red, thick, inner color=red!95!black, outer color=red!75!black},
      top={A},
      left={B},
      right={C},
    }};
  \pic at (6,0) {bell};
\end{tikzpicture}
\end{document}

pic actions代码中的意味着您还可以传递其他选项，这些选项将影响的所有元素pic。但是，这不应与lines和中使用的选项冲突nodes，否则您可能会得到奇怪的结果。（例如，尝试\pic [fill=green!10] {bell};看看我的意思！）

以下是一个例子：

\begin{tikzpicture}
  \pic [rotate=90] {bell};
  \pic at (2,0) [rotate=-90] {bell={nodes={draw, circle, fill=white, inner sep=1pt, font=\sffamily}, top=1, left=2, right=3, cap={draw, fill=gray!25}}};
\end{tikzpicture}

完整代码：

\begin{filecontents}{tikzlibrarybell.code.tex}
% tikzlibrarybell.code.tex
\ProvidesFile{tikzlibrarybell.code.tex}
\pgfdeclarelayer{bell edge layer}
\pgfdeclarelayer{bell node layer}
\pgfsetlayers{bell edge layer,bell node layer,main}
\tikzset{% modified from code at tex/generic/pgf/frontendlayer/tikz/libraries/tikzlibrarybackgrounds.code.tex
  on bell edge layer/.style={%
    execute at begin scope={%
      \pgfonlayer{bell edge layer}%
      \let\tikz@options=\pgfutil@empty%
      \tikzset{every on bell edge layer/.try,#1}%
      \tikz@options%
    },
    execute at end scope={\endpgfonlayer}
  },
  on bell node layer/.style={%
    execute at begin scope={%
      \pgfonlayer{bell node layer}%
      \let\tikz@options=\pgfutil@empty%
      \tikzset{every on bell node layer/.try,#1}%
      \tikz@options%
    },
    execute at end scope={\endpgfonlayer}
  },
  pics/bell/.style={%
    code={%
      \tikzset{%
        /bell/.cd,
        #1,
        /tikz/.cd,
      }%
      \path [use as bounding box] (-2,-2) rectangle (2,2);
      \begin{scope}[on bell node layer]
        \node [pic actions, /bell/node style] (a) at (0, 0.75) {\bell@top@node};
        \node [pic actions, /bell/node style] (b) at (-0.5, 0) {\bell@left@node};
        \node [pic actions, /bell/node style] (c) at (0.5, 0) {\bell@right@node};
      \end{scope}
      \begin{scope}[on bell edge layer]
        \path [pic actions, /bell/cap style] (c.center) [in=0, out=90] to (a.center) [in=90, out=180] to (b.center) [in=270, out=-90, looseness=0.75]  to (c.center);
      \end{scope}
    }%
  },
  /bell/.search also={/tikz},
  /bell/.cd,
  top/.store in=\bell@top@node,
  left/.store in=\bell@left@node,
  right/.store in=\bell@right@node,
  % this cannot be the right way to do this!!!
  cap/.code={\tikzset{/bell/cap style/.style={/tikz/.cd, #1}}},
  nodes/.code={\tikzset{/bell/node style/.style={/tikz/.cd, #1}}},
  top=,
  left=,
  right=,
  cap style/.style={draw},
  node style/.style=,
}
\endinput
\end{filecontents}
\documentclass[tikz,border=10pt,multi]{standalone}
\usetikzlibrary{shapes.geometric,bell}
\begin{document}
\begin{tikzpicture}
  \pic {bell};
  \pic at (2,0) {bell={%
      nodes={fill opacity=.75, text=blue, text opacity=1, inner color=blue!10, outer color=blue!30, font=\sffamily, inner sep=0pt, shape=ellipse},
      cap={draw=blue!50!black, ball color=blue!50, thick},
      top={top},
      left={left},
      right={right},
    }};
  \pic at (4,0) {bell={%
      nodes={text=red, draw=red, thick, fill=white, font=\sffamily, inner sep=1pt, shape=circle},
      cap={draw=red, thick, inner color=red!95!black, outer color=red!75!black},
      top={A},
      left={B},
      right={C},
    }};
  \pic at (6,0) {bell};
\end{tikzpicture}
\begin{tikzpicture}
  \pic [rotate=90] {bell};
  \pic at (2,0) [rotate=-90] {bell={nodes={draw, circle, fill=white, inner sep=1pt, font=\sffamily}, top=1, left=2, right=3, cap={draw, fill=gray!25}}};
\end{tikzpicture}
\end{document}

Answer