[Tex/LaTex] Tikz \draw as part of style (Drawing something inside each node of certain type)

nodestikz-pgftikz-styles

I'm currently learning how to use Tikz and was looking into drawing automata (specifically Simulink-like state models). Currently, I'm making a style that should reduce my efforts to a minimum when drawing these state models. Unfortunately, I can't seem to figure out how to do the following:

To draw two lines relatively to all nodes that use a certain style (in this case Ramp).

This is what I have currently:

\documentclass[preview]{standalone}

\usepackage[dutch]{babel}
\usepackage{mathtools}
\usepackage{mathdots}

\usepackage{pgf}
\usepackage{tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{decorations.pathreplacing}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{automata}
\usetikzlibrary{arrows}

\begin{document}
\tikzstyle{colorful} = [fill=gray!10]
\tikzstyle{block} = [draw, colorful, rectangle, minimum height=3em, minimum width=3em]
\tikzstyle{ramp} = [block, pin={below:Ramp}]
\tikzstyle{sum} = [draw, colorful, circle, node distance=1cm]
\tikzstyle{gain} = [draw, colorful, regular polygon, regular polygon sides=3, shape border rotate=30]
\tikzstyle{integrator} = [block, right=of gain, pin={below:Integrator}]%, node contents = $\frac{1}{s}$]
\tikzstyle{input} = [coordinate]
\tikzstyle{output} = [coordinate]
\tikzstyle{node} = [coordinate]
\tikzset{every pin/.style={pin distance = 1mm}}
\tikzset{every pin edge/.style={draw=none}}
\begin{tikzpicture}[auto, node distance=1cm,>=latex']
    \node [ramp] at (0,0) (input) {};
    \node [block, right=of input] (prod) {$\times$};
    \node [gain, right=of prod] (gain) {$-1$};
    \node [integrator] (system) {$\frac{1}{s}$};

    \node [output, right=of system] (output) {};

    \draw [draw,->] (gain) -- node [name=dy] {$\dot{y}$} (system);
    \draw [draw,->] (system) -- node [name=y] {$y$} (output);
    \draw [draw,->] (input) -- node {$t$} (prod);
    \draw [draw,->] (prod) -- node {} (gain);

    \node [node, below=of y] (node1) {};
    \node [node, below=of prod] (node2) {};
    \draw [->] (y) |- (node1) |- (node2) -- (prod);

    \draw (-1/3,-1/3) -- (-1/10,-1/3) -- (1/3,1/3);
%    \draw (-1/3,-1/3) -- ++(7/30,0) -- ++(13/30,2/3);
\end{tikzpicture}
\end{document}

Either of the lines on the bottom should be drawn relative to every node of style Ramp.

Best Answer

Here are two examples how you can draw in a node using style : 

\documentclass[varwidth,border=50]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\tikzset{
  test1/.style={
    draw=red,
    minimum size=2cm,
    alias=thisone,
    append after command={(thisone.south west) -- (thisone.north east)}
  },
  test2/.style={
    draw=blue,
    minimum size=2cm,
    node contents={\tikz\draw circle(3mm);}
  }
}

\begin{document}
\begin{tikzpicture}
  \draw (0,0) node[test1,]{}
        (3,0) node[test2]{};
\end{tikzpicture}
\end{document}

enter image description here

EDIT: In your concrete example you can add the following style 

\tikzset{
  with axes/.style={
    alias=thisone,
    append after command={
      ([shift={(2.1mm,2.1mm)}]thisone.south west) edge[red] +(2mm,0)
      ++(2mm,0) edge[red] ++(5mm,7mm)
    }
  }
}

And then use it for example in ramp style like this : 

\tikzstyle{ramp} = [block, pin={below:Ramp},with axes]
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