为什么梯形节点的最小高度也会影响宽度？

Question

如果我改变minimum height=...一个trapezium节点，宽度也会改变。

标准矩形节点不会发生这种情况。

\documentclass[border=0pt]{standalone}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{positioning, shapes.geometric, shapes.misc, matrix}
\begin{document}
\begin{tikzpicture}[
    basenode/.style={
        draw=lightgray, align=center,
        text=black, very thick, 
        text height=1.75ex, text depth=.25ex,
        text width=7em, 
    },
    inout/.style={
        basenode,
        minimum height=5ex,
        trapezium,
        trapezium left angle=60, 
        trapezium right angle=120,
    },
    inout2/.style={
        basenode,
        minimum height=7ex,
        trapezium,
        trapezium left angle=60, 
        trapezium right angle=120,
    },
    instruction/.style={
        basenode,  
        minimum height=5ex,
        rounded corners,
    },
    instruction2/.style={
        basenode,  
        minimum height=7ex,
        rounded corners,    
    },
]
\matrix[
    matrix of nodes, row sep=7ex, column sep=7em,
    anchor=base
    ]{
    |[inout]|\texttt{trapezium} & with \texttt{minimum height=5ex}\\
    |[inout2]|\texttt{trapezium} & with \texttt{minimum height=7ex}\\
    |[instruction]|\texttt{rectangle} & with \texttt{minimum height=5ex}\\
    |[instruction2]|\texttt{rectangle} & with \texttt{minimum height=7ex}\\
};
\end{tikzpicture}
\end{document}

Answer 1

这是已知问题。在 tikz 和 pgf 手册中，您可以在第 697 页找到以下内容：

/pgf/trapezium stretches=boolean (默认 true)

此键控制 pgf 是否允许在考虑任何最小尺寸规范时独立放大梯形的宽度和高度。这最初是错误的，确保形状在放大时“看起来相同但更大”。

通过将 hbooleani 设置为 true，梯形可以水平或垂直拉伸。

其中一个例子：

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{shapes.geometric}

\begin{document}
\begin{tikzpicture}[
my node/.style={trapezium, fill=#1!20, draw=#1!75, text=black},
trapezium stretches=true % <---
                    ]
\draw [help lines] grid (3,2);
\node [my node=red] {A};
\node [my node=green, minimum height=1.5cm] at (1, 1.25) {B};
\node [my node=blue, minimum width=1.5cm] at (2, 0) {C};
\end{tikzpicture}
\end{document}