[Tex/LaTex] Drawing a custom node and arrows in tikz

tikz-arrowstikz-pgftikz-styles

I am trying to draw the picture that I have drawn here in paint using tikz. I have managed to get this far (please see the code and the output diagram on the right hand side) but cannot quite get it to be what I want it to be (which is illustrated on the left hand side in the drawing in paint). Namely, there are three things I can't quite do:

Change the box around f to be the irregular quadrilateral rather than a rectangle.
Make the arrow going from the 'b bits' to the box around f not be diagonal and point to the left hand side of the box (rather than the top) but for the arrow not to merge with the arrow from 'l bits', and
I would like an arrow between two nodes that is dashed for the first half, and a standard arrow for the second half.

Any help/suggestions for how to do any one of these things would be greatly appreciated.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzstyle{arrow} = [thick,->,>=stealth]

\begin{document}

\begin{tikzpicture}
[nodes={draw, thick, fill=black!0}]

\node (fone) [rectangle, minimum width=1cm, minimum height=1cm] {$f$};
\node (xone) [draw=none,fill=none, above left=1cm and 0cm of fone] {$b$ bits};
\node (ktwo) [draw=none,fill=none, left of=fone, xshift=-1cm] {$\ell$ bits};
\node (ftwo) [draw=none, fill=none, right of=fone, xshift=1cm]{$\ell$ bits};

\draw [arrow] (xone) -- (fone);[![enter image description here][2]][2]
\draw [arrow] (ktwo) -- (fone);
\draw [arrow] (fone) -- (ftwo);

\end{tikzpicture}
\end{document}

The diagram the code outputs

Best Answer

A solution that does not require you to place everything with specific coordinates is as follows:

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}
\tikzstyle{arrow} = [thick,->,>=stealth]

\usetikzlibrary{shapes,shapes.multipart} % Required for the trapezoid shape
\usetikzlibrary{calc} % Required for the computation of the angle arrow

\begin{document}

\begin{tikzpicture}
% Draw the trapezium and rotate by 90 degrees. A rotation of the text is also needed
\node (fone) [draw,trapezium,trapezium left angle=70,trapezium right angle=0,rotate=-90,minimum width=1cm, minimum height=1cm] {\rotatebox{90}{$f$}};

% Inotrduce a coordinate to lean on for drawing the angle shape
\node[coordinate, left of=fone] (x) {};

\node (xone) [draw=none,fill=none, above of=x,node distance=1.5cm] {$b$ bits};
\node (ktwo) [draw=none,fill=none, left of=fone, xshift=-1cm] {$\ell$ bits};
\node (ftwo) [draw=none, fill=none, right of=fone, xshift=1cm]{$\ell$ bits};

% The following connects xone with the coordinate x at the exact point where
% fone has 245 degrees (Note that it was rotated by 90 deg), then draw the line.
\draw [arrow] (xone) |- ($(x.north east)!(fone.245)!(x.south east)$) |- (fone.245);
\draw [arrow] (ktwo) -- (fone);
\draw [arrow] (fone) -- (ftwo);

\end{tikzpicture}
\end{document}

The resulting scheme is the following:

Related Solutions

[Tex/LaTex] TikZ node placement and arrow drawing

There's a good chance some more elegant solution will appear soon, but here goes:

By using the calc library you can add node halfway between sensors and resources, and position information with relation to this. I actually used the corners of these, resources.south west and sensors.north west, and put the new node midway between these.
One way is to use relative coordinates to first go a little right of processing, then up, left to planning. By using |-/-| you can access coordinates that lie on the intersection of the horizontal line from one node and vertical line from another. That way you can end the arrow directly above sensors.north east, for example.

I first add a new node, lowerright while drawing the line from resources to planning. (lowerright |- container.east) is the point that lies on the vertical line from lowerright and the horizontal line from container.east. Similar for (container.east -| resources.south east).
You can add a node above the top left corner of container.
Add inner sep=<dimension> to the container node, instead of defining width and height. This sets the distance from the contents of the node to the edge of the node.

enter image description here

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{fit,arrows,calc,positioning}

\begin{document}
\tikzstyle{b} = [rectangle, draw, fill=blue!20, node distance=3cm, text width=6em, text centered, rounded corners, minimum height=4em, thick]
\tikzstyle{c} = [rectangle, draw, inner sep=0.5cm, dashed]
\tikzstyle{l} = [draw, -latex',thick]

\begin{tikzpicture}[auto]
    \node [b] (planning) {Planning};
    \node [b, below=of planning] (resources) {Resources};
    \node [b, below=of resources] (sensors) {Sensors};
    \coordinate (RSmid) at ($(resources.south west)!0.5!(sensors.north west)$);
    \node [b, left=of RSmid, node distance=4cm] (information) {Information system};
    \node [b, below=of sensors] (processing) {Processing};

    \node [c,fit=(resources) (sensors)] (container) {};

    \path [l] (planning) -- (resources);
    \path [l] (resources) -- (sensors);
    \path [l] (sensors) -- (processing);

    \path [l] (information) |- (planning);
    \path [l] (information) |- (processing);
    
    \node at (container.north west) [above right] {Desc};
    
    \draw [l] (processing.east) -- ++(2,0) node(lowerright){} |- (planning.east);
    \draw [l] (lowerright |- container.east) -- (container.east -| resources.south east);
\end{tikzpicture}
\end{document}

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

A solution which allows to draw intersection segments of any two intersections is available as tikz library fillbetween.

This library works as general purpose tikz library, but it is shipped with pgfplots and you need to load pgfplots in order to make it work:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}];

\end{tikzpicture}

\end{document}

enter image description here

The key intersection segments is described in all detail in the pgfplots reference manual section "5.6.6 Intersection Segment Recombination"; the key idea in this case is to

create a temporary path temp1 which is the first intersection segment of red and blue, more precisely, it is the first intersection segment in the Left argument in red and blue : red. This path is drawn as thin black path. Substitute its \draw statement by \path to make it invisible.
Compute the desired intersection segment by intersecting temp1 and green and use the correct intersection segment. By trial and error I figured that it is the third segment of path temp1 which is written as L3 (L = left argument in temp1 and green and 3 means third segment of that path).

The argument involves some trial and error because fillbetween is unaware of the fact that end and startpoint are connected -- and we as end users do not see start and end point.

Note that you can connect these path segments with other paths. If such an intersection segment should be the continuation of another path, use -- as before the first argument in sequence. This allows to fill paths segments:

\documentclass{standalone}

\usepackage{tikz}
\usepackage{pgfplots}
\usetikzlibrary{fillbetween}

\begin{document}

\begin{tikzpicture}

\draw [name path=red,red] (120:1.06) circle (1.9);
%\draw [name path=yellow,yellow] (0:1.06) circle (2.12);
\draw [name path=green,green!50!black] (0:0.77) circle (2.41);
\draw [name path=blue,blue] (0:0) circle (1.06);

% substitute this temp path by `\path` to make it invisible:
\draw[name path=temp1, intersection segments={of=red and blue,sequence=L1}];
\draw[red,fill=blue,-stealth,ultra thick, intersection segments={of=temp1 and green,sequence=L3}]  
    [intersection segments={of=temp1 and green, sequence={--R2}}]
;

\end{tikzpicture}

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] TikZ node placement and arrow drawing

[Tex/LaTex] TikZ: Drawing an arc from an intersection to an intersection

Related Question