## Next:BibTeX Style Examples

This tutorial gives a brief introduction in how to draw in LaTeX using the TikZ package. TikZ allows you to create and include vector graphics directly in your LaTeX document.

## TikZ setup

In order to use TikZ you must include the package using the \usepackage{tikz} command. Inside the document you create a new picture using \begin{tikzpicture} and \end{tikzpicture}. Everything in between these two commands is interpreted as an image.

## Drawing lines

You can use the \draw command to specify the coordinates of the line and -- to specify to draw a straight line. Coordinates are in centimeters by default.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) -- (2,4);
\end{tikzpicture}
\end{document}

You can specify a sequence of points for the line and draw multiple lines in one picture. The grid command draws a grid to see where the points exactly are.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) grid (4,3);
\draw (0,0) -- (1,2) -- (3,3) -- (4,2);
\draw (2,0) -- (3,2);
\end{tikzpicture}
\end{document}


## Scaling pictures

You can scale an image up or down by using the scale option.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[scale=0.5]
\draw (0,0) grid (2,2);
\draw (0,0) -- (1,1);
\end{tikzpicture}

\begin{tikzpicture}[scale=2]
\draw (0,0) grid (2,2);
\draw (0,0) -- (1,1);
\end{tikzpicture}
\end{document}


## Drawing arrows

The draw command accepts several different options that change the appearance of the line endings.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [->] (0,2) -- (1,3);
\draw [<-] (1,2) -- (2,3);
\draw [|->] (2,2) -- (3,3);
\draw [<->] (3,2) -- (4,3);
\draw [<->] (1,1) -- (1,0) -- (3,0);
\end{tikzpicture}
\end{document}


## Line thickness

You can change the thickness of every single line so that it matches your requirements. You can use: ultra thin, very thin, thin, semithick, thick, very thick and ultra thick.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [<->] (0,4) -- (0,0) -- (4,0);
\draw [thick] (0,3) -- (3,0);
\draw [ultra thick] (0,0) -- (3,3);
\draw [ultra thin] (2,0) -- (2,2) -- (0,2);
\end{tikzpicture}
\end{document}

You can specify your custom width using the line width option of the \draw command. The default unit is pt.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [<->, line width=1] (0,4) -- (0,0) -- (4,0);
\draw [line width=0.5mm] (0,3) -- (3,0);
\draw [line width=0.1cm] (0,0) -- (3,3);
\draw [line width=0.1] (2,0) -- (2,2) -- (0,2);
\end{tikzpicture}
\end{document}


## Coloring lines

You can give every line a different color. There are several predefined ones but you can also use your own by adding \definecolor{mycolor}{rgb}{0,0.6,0.5} in the preamble of your document.
\documentclass{article}
\usepackage{tikz}
\definecolor{mycolor}{rgb}{0,0.6,0.5}
\begin{document}
\begin{tikzpicture}
\draw [thick, gray] (0,1) -- (2,1);
\draw [thick, mycolor] (0, 0.5) -- (2,0.5);
\draw [thick, blue] (0,0) -- (2,0);
\end{tikzpicture}
\end{document}


## Drawing shapes

You can draw shapes like rectangle, circle, stars, etc. There exist much more. The following example depicts only a few.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [blue] (0,0) rectangle (2,1);
\draw [red, thick] (2,1) circle [radius=0.5];
\draw [green, ultra thick] (0,0.5) ellipse [x radius = 0.5cm, y radius = 1cm];
\end{tikzpicture}
\end{document}