Tikz：在线段上放置坐标（或节点）

Question

我需要与另一条线相交，如下所示：

我正在考虑使用[near start]并使用节点：

\documentclass{article}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \node[label=above:A] (A) at (0,1) {$\bullet$};
        \node[label=above:B] (B) at (1,0) {$\bullet$};
        \node[label=above:C] (C) at (1,1) {$\bullet$};
        
        \draw (A) -- (B) node[near start=1cm, below] {D} node[near start=1cm] {$\bullet$}; 
    \end{tikzpicture}
\end{document}

或者使用坐标，更清晰：

\documentclass{article}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \coordinate (A) at (0,1);
        \draw (A) node[above] {A} node {$\bullet$};
        \coordinate (B) at (1,0);
        \draw (B) node[above] {B} node {$\bullet$};
        \coordinate (C) at (1,1);
        \draw (C) node[above] {C} node {$\bullet$};
        
        \draw (A) -- (B) node[near start=1cm, below] {D} node[near start=1cm] {$\bullet$}; 
    \end{tikzpicture}
\end{document}

我已经放置了标签 D，但我不能再使用它来绘制线 (DC)。有人有什么想法吗？

编辑 ：[near start] 类似于 [pos=0.25]，我认为这是放置节点的更好方法

Answer 1

C只需在所需位置放置一个坐标并单独添加项目符号标签。然后连接和的坐标D：

\documentclass{article}
\usepackage{tikz}
\begin{document}
    \begin{tikzpicture}
        \coordinate (A) at (0,1);
        \draw (A) node[above] {A} node {$\bullet$};
        \coordinate (B) at (1,0);
        \draw (B) node[above] {B} node {$\bullet$};
        \coordinate (C) at (1,1);
        \draw (C) node[above] {C} node {$\bullet$};
        
        \draw (A) -- (B) node[near start=1cm, below] {D} coordinate[near start=1cm] (D); 
        \node at (D) {$\bullet$};
        \draw (D) -- (C);
    \end{tikzpicture}
\end{document}

Answer 2

使用calc库，您可以控制节点的位置D，例如，

\coordinate (D) at ($(A)!0.25!(B)$);

然后从C 到绘制D。

\documentclass[margin=3mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
    \begin{tikzpicture}
        \coordinate (A) at (0,1);
        \draw (A) node[above] {A} node {$\bullet$};
        \coordinate (B) at (1,0);
        \draw (B) node[above] {B} node {$\bullet$};
        \coordinate (C) at (1,1);
        \draw (C) node[above] {C} node {$\bullet$};
        \coordinate (D) at ($(A)!0.25!(B)$);
        \draw (D) node[below] {D} node {$\bullet$};
        \draw (A) -- (B) ;
        \draw (C) -- (D);
    \end{tikzpicture}
\end{document}

Answer 3

只是更紧凑的语法

\documentclass[tikz, border=2mm]{standalone}
\begin{document}
\begin{tikzpicture}[%
    point/.style={circle, draw, thin, fill=blue, minimum size=2pt, inner sep=0pt},
    text=blue, font=\sffamily\scriptsize, label distance=-2pt]
    \draw[thick] (0,1) node[point, label=A]{} -- node[near start, point, label=D] (d) {} (1,0) node[point, label=B] {};
    \draw[thick] (d) -- (1,1) node[point, label=C]{};
\end{tikzpicture}
\end{document}