![tikz:命名路径的端点](https://linux22.com/image/428829/tikz%EF%BC%9A%E5%91%BD%E5%90%8D%E8%B7%AF%E5%BE%84%E7%9A%84%E7%AB%AF%E7%82%B9.png)
我有一个简单的 tikzsketch,它绘制一个相对于三角形中心并垂直于其一条边的矢量。
我想在草图中的蓝色箭头尖端绘制另一条路径(矢量)。我想我要做的是命名路径末端的坐标,但不确定如何执行此操作的语法。
如何在计算路径中捕获/命名坐标?
\documentclass[border=20pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{intersections, calc,through,backgrounds}
\begin{document}
\begin{tikzpicture}[scale=2]
% Coordinates for a triangle
\coordinate (P) at ($(0,0) + (rand,rand)$);
\coordinate (Q) at ($(2,-2) + .5*(rand, rand)$);
\coordinate (R) at ($(-2, -2) + .5*(rand, rand)$);
\coordinate (O) at (barycentric cs:P=1,Q=1,R=1) ;
%projection of O on PQ
%use this for the intersection point for the vector below
\coordinate (E) at ($(P)!(O)!(Q)$);
% Vector perpendicular to edge PQ and located at O
% I would like to get the coordinate at the tip of this vector
\draw[->, blue] let
\p1 = ($(P)-(Q)$)
in
(O)--node[midway, sloped, above]{$\vec{A}$}node[above,at end]{${\color{black}S}$}++($(O)!sqrt(\x1*\x1+\y1*\y1)!(E)-(O)$);
%\fill[red](S)circle(2pt)
\draw[thin] (P) -- (Q) -- (R) --cycle;
\end{tikzpicture}
\end{document}
答案1
我认为我已经在你第一个问题中回答过这个问题了。
在下一行中:您可以在绘制点 S 之前
(O)--node[midway, sloped, above]{$\vec{A}$}node[above,at end]{${\color{black}S}$}++($(O)!sqrt(\x1*\x1+\y1*\y1)!(E)-(O)$);
添加。coordinate[at end](S)
然后你得到:
(O)--node[midway, sloped, above]{$\vec{A}$} coordinate[at end](S) node[above,at end]{${\color{black}S}$}++($(O)!sqrt(\x1*\x1+\y1*\y1)!(E)-(O)$);
答案2
\documentclass[border=20pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{intersections, calc,through,backgrounds}
\begin{document}
\begin{tikzpicture}[scale=2]
% Coordinates for a triangle
\coordinate (P) at ($(0,0) + (rand,rand)$);
\coordinate (Q) at ($(2,-2) + .5*(rand, rand)$);
\coordinate (R) at ($(-2, -2) + .5*(rand, rand)$);
\coordinate (O) at (barycentric cs:P=1,Q=1,R=1) ;
%projection of O on PQ
%use this for the intersection point for the vector below
\coordinate (E) at ($(P)!(O)!(Q)$);
% Vector perpendicular to edge PQ and located at O
% I would like to get the coordinate at the tip of this vector
\draw[->, blue] let
\p1 = ($(P)-(Q)$)
in
(O)--
node[midway, sloped, above]{$\vec{A}$}
coordinate[at end, label=aux, fill=red, circle, inner sep=0.5pt ]
++(
$(O)!sqrt(\x1*\x1+\y1*\y1)!(E)-(O)$
);
% \fill[red](aux)circle(2pt)
\draw[thin] (P) -- (Q) -- (R) --cycle;
\end{tikzpicture}
\end{document}