[Tex/LaTex] Tikz: draw a vector pointing from one point to another

tikz-pgf

I have two points:

\coordinate (A) at (1,2);
\coordinate (B) at (13.2,-23.4);

I would like to draw a vector pointing from point A to point B. The vector starts from point A, its length is other specified, and its end is not at point B. See the figure below. Is there an automatic way to draw the arrow such that I need not to calculate the coordinate of the end of the arrow every time?

enter image description here

Best Answer

Additional to shorten, you could be interested in the calc library.

Code

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,arrows}
\begin{document}
\begin{tikzpicture}
\coordinate (A) at (-1,5);
\coordinate (B) at (1,2);
\tikzset{-|}
\draw [|-|,help lines] (A) -- (B);
\draw[black,very thick] (A) -- ($(B)!1cm!(A)$); % 1 cm before B
\draw[blue, thick] (A) -- ($(A)!.65!(B)$);      % 65 % on the path from A to B
\draw[green] (A) -- ($(B)!.45!(A)$);            % 45 % on the path from B to A (55% from A to B)
\end{tikzpicture}
\end{document}

Output

Related Solutions

[Tex/LaTex] Draw consecutive arrows with TikZ

If you use \coordinate instead of \node, you won't get the gaps. And you can set different arrow tips for the different edges, so try

\draw (a) edge[-|] (b)  edge[-|] (c)  edge[->] (d);

I added a markings version as well, for reference.

\documentclass[tikz,border=5pt]{standalone}    
\usepackage{tikz}
\usetikzlibrary{decorations.markings}

\begin{document}

\begin{tikzpicture}

\coordinate (a) at (0,0);
\coordinate (b) at (2,0);
\coordinate (c) at (7,0);
\coordinate (d) at (10,0);

\draw (a) edge[-|] (b)  edge[-|] (c)  edge[->] (d);

\end{tikzpicture}

\begin{tikzpicture}[
 decoration={markings,
             mark=at position 0.2 with \arrow{|},
             mark=at position 0.7 with \arrow{|}}
]
\coordinate (a) at (0,0);
\coordinate (d) at (10,0);

\draw [->,postaction={decorate}] (0,0) -- (10,0);

\end{tikzpicture}
\end{document}

[Tex/LaTex] TikZ Can I draw an arrow by specifying the initial point, direction, and length

Here is a version that modifies the to path. So you need to replace -- by to, and to apply the style, e.g.

\draw[pft] (-6, -3) to (0, -3) to (-4,0) to cycle;

The to path is modified in such a way that a sloped arrow (from the shapes.arrows library) is attached in the middle of the path. allow upside down is used to avoid that TikZ intelligently rotates the arrows in a way that is appropriate for texts. I also would use symbolic coordinates, and the nodes can be placed in the centers of the triangles with barycentric cs:.

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{shapes.arrows}
\begin{document}

\begin{tikzpicture}[pft/.style={to path={--(\tikztotarget)
    node[midway,above=0.6em,marrow,allow upside down]{}}},
    marrow/.style={sloped,fill, minimum height=3cm, single arrow, single arrow
    head extend=.5cm, single arrow head indent=.25cm,xscale=0.3,yscale=0.15}]
 \path (-6, -3) coordinate (A)  (6, -3) coordinate (B) (-2, 3) coordinate (C)
  (A) -- (B) coordinate[midway] (AB) (B) -- (C) coordinate[midway] (BC)         
  (C) -- (A) coordinate[midway] (CA);   
 \draw[pft] (A) to (AB) to (CA) to cycle
    (AB) to (B) to (BC) to cycle
    (CA) to (BC) to (C) to cycle
    (CA) to (AB) to (BC) to cycle;
 \path (barycentric cs:A=1,AB=1,CA=1) node{$T_1^{(1)}$}
  (barycentric cs:AB=1,BC=1,CA=1) node{$T_2^{(1)}$}
  (barycentric cs:CA=1,BC=1,C=1) node{$T_3^{(1)}$}
 (barycentric cs:B=1,AB=1,BC=1) node{$T_4^{(1)}$};
\end{tikzpicture}
\end{document}