[Tex/LaTex] TikZ: placing square brackets (or open rectangles) perpendicular to lines forming a circle

tikz-pgf

I am drawing a little sketch depicting an experiment (code below):
enter image description here

At the arrows (under % Outgoing lines in the code) to the right I would like to place little rectangles with their long side perpendicular to each arrow (what would be even better if those rectangles were more like square brackets, i.e. unfilled rectangles with thick lines and the long side closer to the arrow not drawn). The size of such a rectangle should be just big enough so that the heads of the upper two lines can "fit" into one.

Since I have defined the arrows to have the same length and just point away from a certain central point under different angles, their end points essentially lie on a circle.

Any ideas how I can achieve what I outlined above?

\documentclass[article]

\usepackage{tikz}
\usetikzlibrary[patterns]

\begin{document}

\pagestyle{empty}

\begin{tikzpicture}

    % Beam, upper border
    \fill[draw opacity=0,pattern color=gray,pattern=horizontal lines] (-2,0.8) rectangle (2,-0.8);
    % Beam direction
    \draw[->,thick] (-1.5,0) -- (1.5,0);
    \draw[latex-] (1.0,0.5) -- ++(80:1.5cm) node[right]{Beam};

    % Slit, uppper part
    \fill[black] (-0.125,3) rectangle (0.125,0.8);
    % Slit, lower part
    \fill[black] (-0.125,-0.8) rectangle (0.125,-3);

    % Target
    \draw[pattern=north east lines]  (1.9,0.7) rectangle (2.1,-0.7);
    \draw[latex-] (2.0,-0.7) -- ++(260:1.5cm) node[right]{Target};

    % Outgoing lines
    \draw[->] (2.2,0.0) -- +(45:2cm);
    \draw[->] (2.2,0.0) -- +(35:2cm);
    % Area element
    \draw[<->] (2.2,0.0) +(35:1.5cm) arc [start angle=35,delta angle=10,radius=1.5cm];
    \draw[-latex] (2.2,0.0) ++(38:1.5cm) ++(0cm,1cm) node[above]{$d$} -- ++(0cm,-0.95cm);

    \draw[->] (2.2,0.0) -- +(0:2cm);
    \draw[->] (2.2,0.0) -- +(-45:2cm);

\end{tikzpicture}

\end{document}


\usepackage{tikz}
\usetikzlibrary[patterns]

\begin{document}

\pagestyle{empty}

\begin{tikzpicture}

    % Beam, upper border
    \fill[draw opacity=0,pattern color=gray,pattern=horizontal lines] (-2,0.8) rectangle (2,-0.8);
    % Beam direction
    \draw[->,thick] (-1.5,0) -- (1.5,0);
    \draw[latex-] (1.0,0.5) -- ++(80:1.5cm) node[right]{Beam};

    % Slit, uppper part
    \fill[black] (-0.125,3) rectangle (0.125,0.8);
    % Slit, lower part
    \fill[black] (-0.125,-0.8) rectangle (0.125,-3);

    % Target
    \draw[pattern=north east lines]  (1.9,0.7) rectangle (2.1,-0.7);
    \draw[latex-] (2.0,-0.7) -- ++(260:1.5cm) node[right]{Target};

    % Outgoing lines
    \draw[->] (2.2,0.0) -- +(45:2cm);
    \draw[->] (2.2,0.0) -- +(35:2cm);
    % Area element
    \draw[<->] (2.2,0.0) +(35:1.5cm) arc [start angle=35,delta angle=10,radius=1.5cm];
    \draw[-latex] (2.2,0.0) ++(38:1.5cm) ++(0cm,1cm) node[above]{$d$} -- ++(0cm,-0.95cm);

    \draw[->] (2.2,0.0) -- +(0:2cm);
    \draw[->] (2.2,0.0) -- +(-45:2cm);

\end{tikzpicture}

\end{document}

Best Answer

Method 1: Square Brackets:

If you simply want to add a square bracket, you can simply add a node and rotate it:

\draw[->] (2.2,0.0) -- +(45:2cm) node [rotate=45] {]};

If you want it a different size you can use scalebox:

\draw[->] (2.2,0.0) -- +(35:2cm) node [rotate=35] {\scalebox{0.5}{]}};

enter image description here

Method 1: Draw the Shape:

However, a better solution is to draw the desired shape with something like:

\newcommand{\DrawBrac}[2][]{%
    \draw [red, thick, #1]  #2%                    Start at given coordinate
           ++(-0.5ex, 0.5ex) -- ++( 0.5ex, 0.0ex)% Top Horizontal Line
        -- ++( 0.0ex,-1.0ex)%                      Vertical Line
        -- ++(-0.5ex, 0.0ex)%                      Bottom Horizontal Line
 }

Here you can adjust the sizing of this precisely, but with the current values, this yields:

enter image description here

Code: Square Brackets

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary[patterns]

\begin{document}
\pagestyle{empty}

\begin{tikzpicture}
    % Beam, upper border
    \fill[draw opacity=0,pattern color=gray,pattern=horizontal lines] (-2,0.8) rectangle (2,-0.8);
    % Beam direction
    \draw[->,thick] (-1.5,0) -- (1.5,0);
    \draw[latex-] (1.0,0.5) -- ++(80:1.5cm) node[right]{Beam};

    % Slit, uppper part
    \fill[black] (-0.125,3) rectangle (0.125,0.8);
    % Slit, lower part
    \fill[black] (-0.125,-0.8) rectangle (0.125,-3);

    % Target
    \draw[pattern=north east lines]  (1.9,0.7) rectangle (2.1,-0.7);
    \draw[latex-] (2.0,-0.7) -- ++(260:1.5cm) node[right]{Target};

    % Outgoing lines
    \draw[->] (2.2,0.0) -- +(45:2cm) node [red,rotate=45] {]};
    \draw[->] (2.2,0.0) -- +(35:2cm) node [red,rotate=35,line width=8pt] {]};
    % Area element
    \draw[<->] (2.2,0.0) +(35:1.5cm) arc [start angle=35,delta angle=10,radius=1.5cm] ;
    \draw[-latex] (2.2,0.0) ++(38:1.5cm) ++(0cm,1cm) node[above]{$d$} -- ++(0cm,-0.95cm);

    \draw[->] (2.2,0.0) -- +(0:2cm)  node [red,rotate=0] {]};
    \draw[->] (2.2,0.0) -- +(-45:2cm) node [red,rotate=-45] {]};
\end{tikzpicture}
\end{document}

Code: Draw the Shape:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{patterns}

\newcommand{\DrawBrac}[2][]{%
    \draw [red, thick, #1]  #2%                    Start at given coordinate
           ++(-0.5ex, 0.5ex) -- ++( 0.5ex, 0.0ex)% Top Horizontal Line
        -- ++( 0.0ex,-1.0ex)%                      Vertical Line
        -- ++(-0.5ex, 0.0ex)%                      Bottom Horizontal Line
 }

\begin{document}
\pagestyle{empty}

\begin{tikzpicture}
    % Beam, upper border
    \fill[draw opacity=0,pattern color=gray,pattern=horizontal lines] (-2,0.8) rectangle (2,-0.8);
    % Beam direction
    \draw[->,thick] (-1.5,0) -- (1.5,0);
    \draw[latex-] (1.0,0.5) -- ++(80:1.5cm) node[right]{Beam};

    % Slit, uppper part
    \fill[black] (-0.125,3) rectangle (0.125,0.8);
    % Slit, lower part
    \fill[black] (-0.125,-0.8) rectangle (0.125,-3);

    % Target
    \draw[pattern=north east lines]  (1.9,0.7) rectangle (2.1,-0.7);
    \draw[latex-] (2.0,-0.7) -- ++(260:1.5cm) node[right]{Target};

    % Outgoing lines
    \draw[->] (2.2,0.0) -- +(45:2cm) coordinate (A);
    \DrawBrac[rotate=45]{(A)};
%\draw[red, thick,rotate=45] (A) ++(-0.5ex,0.5ex) -- ++(0.5ex,0.0ex) -- ++(0.0ex,-1.0ex) -- ++(-0.5ex,0.0ex);

    \draw[->] (2.2,0.0) -- +(35:2cm)  coordinate (B);
    \DrawBrac[rotate=35]{(B)};
    % Area element
    \draw[<->] (2.2,0.0) +(35:1.5cm) arc [start angle=35,delta angle=10,radius=1.5cm] ;
    \draw[-latex] (2.2,0.0) ++(38:1.5cm) ++(0cm,1cm) node[above]{$d$} -- ++(0cm,-0.95cm);

    \draw[->] (2.2,0.0) -- +(0:2cm)   coordinate (C);
    \DrawBrac{(C)};
    \draw[->] (2.2,0.0) -- +(-45:2cm)   coordinate (D);
    \DrawBrac[rotate=-45]{(D)};
\end{tikzpicture}
\end{document}

Related Solutions

[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)

[Tex/LaTex] How to define the default vertical distance between nodes

I don't really get the question so I hope this is what you wanted. If you include a full document (such that we copy paste and see the problem on our systems) things are much more easier.

Here, you can change the default setting within a scope but your block style had a node distance which was resetting every time it is issued. I've made it 2mm such that we can see the difference easier.

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows,shapes.geometric,positioning}

\begin{document}
\begin{tikzpicture}[decision/.style={diamond, draw, text width=4.5em, text badly centered, node distance=3.5cm, inner sep=0pt},
                    block/.style   ={rectangle, draw, text width=6em, text centered, rounded corners, minimum height=4em, minimum height=2em},
                    cloud/.style   ={draw, ellipse, minimum height=2em},
                    line/.style    ={draw,-latex'},
                    node distance = 1cm, 
                    auto]
    \node [block] (1st) {1st};
    \node [block, right= of 1st]  (2nd1) {2nd1};
\begin{scope}[node distance=2mm and 10mm]%Here we change it for everything inside this scope
    \node [block, above= of 2nd1] (2nd2) {2nd2};
    \node [block, below= of 2nd1] (2nd3) {2nd3};
    \node [block, right= of 2nd1] (3rd1) {3rd1};
    \node [block, above= of 3rd1] (3rd2) {3rd2};
    \node [block, above= of 3rd2] (3rd3) {3rd3};
\end{scope}
    \node [block, below= of 3rd1] (3rd4) {3rd4};
    \node [block, below= of 3rd4] (3rd5) {3rd5};

    \path [line] (1st) -- (2nd1);
    \path [line] (2nd1) -- (2nd2);
    \path [line] (2nd1) -- (2nd3);
    \path [line] (2nd2) -- (3rd3);
    \path [line] (2nd1) -- (3rd1);
    \path [line] (1st) -- (2nd1);
\end{tikzpicture}
\end{document}

enter image description here

Best Answer

Method 1: Square Brackets:

Method 1: Draw the Shape:

Code: Square Brackets

Code: Draw the Shape:

Related Solutions

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

[Tex/LaTex] How to define the default vertical distance between nodes

Related Question