Tikz-Pgf Graphics – How to Create Graphs, Fill in Boxes, and Put Labels Using TikZ

graphicstikz-pgf

I need to make the following graph.

And I carry the following, with the following code,

\begin{center}

 \begin{tikzpicture}[scale=.9]

\draw[<->] (-1,0) -- (2*pi,0) node[below] {$x$};

\draw[thick] (4,0)--(4,1/2);

\draw[thick] (4,0)--(4,-1/2);

\draw[thick] (1.3,1/2)--(1.3,-1/2);

\draw[thick] (2.6,1/2)--(2.6,-1/2);

\draw (0,-1/6) node[left] {};

\draw[<->] (0,-1) -- (0, 3) node[left] {$y$};

\draw[-,domain = 0:4,thick]

 plot (\x,{1/2}) node[right] {};

\draw[-,domain = 0:4,thick]

 plot (\x,{-1/2}) node[right] {};

 \end{tikzpicture}

\end{center}

I would need to fill in the table and put the labels. Someone could help me on that, thanks.

Best Answer

You can put the labels with \nodes the same way as you did in the axes. For the filling the TikZ library patterns could be helpful. And finally, you can draw the brace with the library decorations.pathreplacing.

I changed your original scale, otherwise the text will be very big, in my opinion. You can revert that or change the text size if you want.

The code:

\documentclass[border=2mm,tikz]{standalone}
\usetikzlibrary{patterns}
\usetikzlibrary{decorations.pathreplacing} % for the overbrace

\tikzset%
{% this sytle provides the overbrace (form decorations.pathreplacing)
  mybrace/.style={decorate,decoration={brace,raise=2mm,amplitude=3pt}},
}

\begin{document}
\begin{tikzpicture}[scale=1.5,line join=round,line cap=round]
% axes
\draw[<->] (-1,0) -- (2*pi,0) node[below] {$x$};
\draw[<->] (0,-1) -- (0, 3)   node[left]  {$y$};
% big rectangle (and nodes, labels)
\draw[thick] (0,-1/2) node [below left] {\strut$x=0$} -- (4,-1/2) node [below] {\strut$x=\ell$} |- (0,1/2);
% filled rectangle (and another node)
\draw[thick,pattern=north east lines] (1.3,-1/2) node [below] {\strut$x$} rectangle (2.6,1/2);
% one more node
\node at (2.6,-1/2) [below] {$x+\Delta x$};
% overbrace
\draw[mybrace]   (1.3,1/2) -- (2.6,1/2) node[midway,yshift=5mm] {\strut $\Delta x$};
\end{tikzpicture}
\end{document}

Related Solutions

TikZ PGF – Fixing Dimension Too Large Error with exp(x) in pgfplots

In your question title it mentions pgfplots but you don't use it. And if you don't use r(radian) indicator everything runs smoothly. I'll take the easy way out by just giving a simple pgfplots example.

\documentclass{article}
\usepackage{pgfplots}
\begin{document}
\begin{tikzpicture} 
\begin{axis}[xmin=-0.5,xmax=5,ymin=-0.5,ymax=5,no markers,samples=50,grid=both]
\addplot {exp(x)};
\addplot {ln(x)};
\addplot {x};
\end{axis}
\end{tikzpicture}
\end{document}

enter image description here

Please see the pgfplots manual for a lot more.

[Tex/LaTex] Drawing rectilinear curves in Tikz, aka an Etch-a-Sketch drawing

\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(-3,0) -- ++(45:3);

Use ++ before each new incremental coordinate to make it relative to the last one and put the pencil there.

Here's a complete example:

\documentclass{article}
\usepackage{tikz}
\begin{document}
\tikz\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(-3,0) -- ++(30:3) {[rounded corners=10pt]-- ++(5,0) -- ++(0,-6)} -- ++(-7,0) -- cycle;
\end{document}

Of course, combining this with the -| or |- path operators can simplify the code even further; the following two pieces of code produce the same result:

\tikz\draw (20,12) -- ++(2,0) -- ++(0,2) -- ++(3,0) -- ++(0,1) -- ++(1,0) -- ++(0,-3) -- ++(2,0);\par\bigskip

and

\tikz\draw (20,12) -| ++(2,2) -| ++(3,1) -- ++(1,0) |- ++(2,-3);

I don't think that defining commands in this case adds anything; in fact, I think it reduces the functionality of the existing syntax (which is already simple). The example demonstrates that you can use, for example, polar coordinates and modify (up to TikZ limitations) the path attributes midways; even if the current question doesn't require this, it's a good thing to have the possibility to do those kind of modification if they are required.

Best Answer

Related Solutions

TikZ PGF – Fixing Dimension Too Large Error with exp(x) in pgfplots

[Tex/LaTex] Drawing rectilinear curves in Tikz, aka an Etch-a-Sketch drawing

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