# 9.5 Drawing a pie chart

Pie charts are popular for showing proportions. A pie chart’s main characteristic is that all items usually sum up to 100 percent. They are displayed as segments of a disc.

## How to do it…

We will use the pgf-pie package, which builds on TikZ and is specialized for generating pie charts. Follow these steps:

\documentclass{article}

\usepackage{pgf-pie}

3. Begin the document:
\begin{document}

4. Begin a TikZ picture, which will be the container of the pie chart:
\begin{tikzpicture}

5. Draw the pie chart using this command:
\pie [rotate = 180]
{62/\TeX\ Live and Mac\TeX,
32/MiK\TeX\ and Pro\TeX t, 6/Other \TeX}

6. End the TikZ picture and the entire document:
\end{tikzpicture}
\end{document}

7. Compile and take a look at the result:

## How it works…

The \pie command is the only command in the pgf-pie package. The syntax is as follows:

\pie[options]{number1/text1, number2/text2, }

The backslashes in our example were just because of the \TeX macro and the following space.

Let’s take a look at the available options, with example values:

• pos = 4,6: This positions the center at point (4,6). The default center is (0,0).
• rotate = 90: This rotates the chart by 90 degrees.
• radius = 5: This sets the chart’s radius size to 5. The default size is 3.
• color = red: This chooses the color red for all the slices. The xcolor (and TikZ) syntax, such as red!80!black, will be understood.
• color = {red!20, red!40, red!60}: This sets a specific red color value for each of the three slices.
• explode = 0.1: This moves all the slices outwards by 0.1.
• explode = { 0.2, 0, 0}: This moves only the first slice of the three outwards by 0.2.
• sum = 50: This defines the reference sum as 50, instead of the default sum of 100.
• sum = auto: This calculates the sum from the slice values.
• scale font: This scales the font size according to the slice value.
• before number = { \\$ }: This inserts text before the values, in this case a dollar sign. It is empty by default.
• after number = { percent }: This adds text after each value, in this case the word percent. With sum = 100, the default is %; otherwise, it is empty.
• text = pin: This sets the text next to the slice, connected by a short line.
• text = inside: This places the text within the slice.
• text = legend: This produces a separate legend.

## There’s more…

The pie-chart package offers further chart designs. Let’s take a look at them, together with applying some of the styles we just covered.

### Square chart

The square option gives a quadratic design. Adding the scale font and color option, we arrive at this:

\pie [square, scale font,
color = {blue!10, blue!20, blue!40}] { ... }

With the values from our recipe, we get the following:

### Polar area chart

The polar option changes the layout so that the slices get equal angles but the radius represents the size. We add the explode and text=legend options:

\pie [polar, explode=0.1, text=legend] { ... }

Thus, we get this output:

### Cloud chart

The cloud option produces a set of discs whose sizes are according to the given values. This time, we put the text inside, scale it, and use a larger radius:

\pie [cloud, text=inside, scale font, radius=6] { ... }

Now, the result is as follows:

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