[Tex/LaTex] Shaded triangle arrow with text

tikz-arrowstikz-pgf

I have been trying to recreate a similar version of the arrow shown in the image below.

enter image description here

And this is what I manage to get so far:

enter image description here

I am a complete beginner when it comes to TikZ and after multiple failed attempts, I had to resort to drawing a shaded rectangle and then using right=of rectangle to append a triangle. However, obviously, the approach is awful. There's also a gap between the "arrowhead" and the line. Initially, I tried using using triangle 90,triangle 45 and so forth, but I the height of the arrowhead seemed to be dependent on the length of the line (which I did not like), and also I could not figure out how to add text within the line. Here's what I have:

MWE

\documentclass[border=5mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,shapes}

\begin{document}
\begin{tikzpicture}[font=\large]
  \tikzset{
    node distance=0cm,
    buffer/.style={
      shape border rotate=270,
      regular polygon,
      regular polygon sides=3,
      minimum height=2cm,
      fill=blue!50,
    }
  }

  \node (therectangle) at (0,0) [shade,shading=axis,left color=white,right color=blue!50,minimum width=2.5cm,minimum height=1cm,] {Codes for};

  \node [buffer,right=of therectangle] {};
\end{tikzpicture}%

\end{document}

What I want is an arrow like shown in the picture, giving me the ability to:

Add text within.
Make it shaded.
Be able to use below=of <whatever> etc.
Retain the ability to use shorten <= <whatever> etc.
(Optional) Start the shading from the arrowhead.

Could someone help with this?

Best Answer

As it's a node, you can't use shorten, but the single arrow shape does most of what you want I think.

\documentclass[border=5mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,shapes}

\begin{document}
\begin{tikzpicture}[font=\large]
  \node (therectangle) at (0,0) [single arrow,
                                 text width=3cm,
                                 align=center,
                                 shade,shading=axis,
                                 left color=white,right color=blue!50,
                                 minimum width=2.5cm,minimum height=1cm,] {Codes for};

\end{tikzpicture}%

\end{document}

Concerning your original code, setting the outer sep to zero for both nodes removes the gap, i.e.

\documentclass[border=5mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning,shapes}

\begin{document}
\begin{tikzpicture}[font=\large]
  \tikzset{
    node distance=0cm,
    buffer/.style={
      shape border rotate=270,
      regular polygon,
      regular polygon sides=3,
      minimum height=2cm,
      fill=blue!50,
    }
  }

  \node (therectangle) at (0,0) [shade,shading=axis,left color=white,right color=blue!50,minimum width=2.5cm,minimum height=1cm,outer sep=0pt] {Codes for};

  \node [buffer,outer sep=0pt,right=of therectangle] {};
\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] 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}

MWE

Best Answer

Related Solutions

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

[Tex/LaTex] TikZ node placement and arrow drawing

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