Tikz bend edges ‘adding arrowhead’

arrowsedgetikz-pgf

So i am trying to make a flowchart with tikz. Everything was working fine and as expected. But then I tried to specify starting and endpoints of edges between some rectangles and out of nowhere tikz seems to add an additional arrowhead to the start of my edge.

See the MWE:

\documentclass[border=0.2cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
    \begin{tikzpicture}[font=\small,thick]
        \node[draw,
        minimum width=2.5cm,
        minimum height=1cm
        ] (test1) {test1};
        \node[draw,
        left=of test1,
        minimum width=2.5cm,
        minimum height=1cm
        ] (test2) {test2};
        \draw[-latex] (test1.180) edge [bend left=45] (test2.-90);
        \draw[-latex] (test1) edge [bend right=45] (test2);
    \end{tikzpicture}
\end{document}

For some reason the first edge has an additional arrowhead at the start of the edge (at node test1). How do I get rid of the unwanted arrowhead?

Also, is there a way for an edge starting at a rectangle node to properly fill out the empty space near the border?

Best Answer

Like this?

I would define edge as shown in MWE below:

\documentclass[border=0.2cm]{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}
    \begin{tikzpicture}[
box/.style = {draw, thick, 
              minimum width=2.5cm, minimum height=1cm},
every edge/.style = {draw, -latex, thick} % <---
                        ]
\node[box] (test1) {test 1};
\node[box, left=of test1] (test2) {test 2};
%
\draw   (test1.180) edge [bend left=45] (test2.-90) 
        (test1)     edge [bend right=45] (test2);
    \end{tikzpicture}
\end{document}

Related Solutions

[Tex/LaTex] Align edges with anchor other than center

I'm not sure to understand exactly the question . I understand that : you want an edge between two nodes but you want to draw the edge only between the intersections of the edges and the shapes of the nodes.

With intersections (the problem is to make a choice between the points) but in the second method I just fill the node's background.

\documentclass{scrartcl}
\usepackage{tikz}
\usetikzlibrary{positioning,intersections}
\begin{document}

\begin{tikzpicture}
  \node[name path= c1] (foo)  at (0,0)[circle] {$x$};
  \node[name path= c2] (bar) at (2,2)[circle] {$x+1$};
  \path[name path=line] (foo.south) -- (bar.center);
  \fill [name intersections={of=c1 and line, name=i, total=\t}]
 [red, opacity=0.5, every node/.style={left=.25cm, black, opacity=1}] 
 \foreach \s in {1,...,\t}{(i-\s) circle (2pt) node {}};
  \fill [name intersections={of=c2 and line, name=j, total=\t}]
 [red, opacity=0.5, every node/.style={left=.25cm, black, opacity=1}] 
 \foreach \s in {1,...,\t}{(j-\s) circle (2pt) node {}};   
  \draw[red] (i-1) -- (j-1);  
\end{tikzpicture} 
\begin{tikzpicture}
  \node[name path= c1] (foo)  at (0,0)[circle] {$x$};
  \node[name path= c2] (bar) at (2,2)[circle] {$x+1$};
  \path[name path=line] (foo.south) -- (bar.center);
  \path [name intersections={of=c1 and line, name=i, total=\t}] ;
  \path [name intersections={of=c2 and line, name=j, total=\t}];  
  \draw[red] (i-1) -- (j-1);  
\end{tikzpicture}
\begin{tikzpicture}
  \node (foo)  at (0,0)[circle] {\hphantom{$x$}};
  \node (bar) at (2,2)[circle] {\hphantom{$x+1$}};
  \draw[red] (foo.south) -- (bar.center);
  \node[circle,fill=white] at (foo.center){$x$} ;
  \node[circle,fill=white] at (bar.center){$x+1$} ; 
\end{tikzpicture}  
\end{document}

enter image description here

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

The source of the difficulty is that ellipses are constructed in a particular way in TikZ. They are paths that start from the x-axis and proceed counter-clockwise around their centre. The vast majority of the time, the exact parametrisation doesn't matter. You appear to have found the one situation where it does!

In the actual question, you only want to be able to mirror the ellipse, and so draw it starting from the negative x-axis (the title of the question suggests a more flexible approach). That's actually not too hard since we can exploit the symmetry of the ellipse. The key is to provide it with a negative x-radius, since then it will start from the negative x-axis (and proceed clockwise, but we could correct for that by negating the y-radius as well). To do this, we interrupt the call from the node shape to the drawing command and flip the sign of the x-radius. The simplest way to do this is to redefine the \pgfpathellipse macro to do the negation and then call the original macro. The following code does this.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations,shapes,decorations.markings}
\makeatletter
\let\origpgfpathellipse=\pgfpathellipse
\def\revpgfpathellipse#1#2#3{%
  #2%
  \pgf@xa=-\pgf@x
  \origpgfpathellipse{#1}{\pgfqpoint{\pgf@xa}{0pt}}{#3}}
\makeatother

\tikzset{
  reversed ellipse/.style={
    ellipse,
    reverse the ellipse%
  },
  reverse the ellipse/.code={
    \let\pgfpathellipse=\revpgfpathellipse
  }
}
\begin{document}
\begin{tikzpicture}
\node[ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,0) {hello world};

\node[reversed ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,-2) {hello world};
\end{tikzpicture}

\end{document}

Here's the result:

rotated ellipse

(the arrow got clipped, but you can see where it lies)

Best Answer

Related Solutions

[Tex/LaTex] Align edges with anchor other than center

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

Related Question