View source for Template:Pie chart/doc

{{Documentation subpage}}
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=== Usage ===
The labels and values of up to 30 slices may be specified. All the parameters for six slices are included below; to include more slices, copy the code for one of the others, changing the digit at the end of each parameter name.
<pre><nowiki>
{{Pie chart
| thumb = 
| caption = 
| other = 
| label1 =remember 
| value1 =16.6
| color1 =2
| label2 =understand
| value2 =16.6
| color2 =3 
| label3 =apply
| value3 =16.6 
| color3 =5 
| label4 =analyze
| value4 =16.6
| color4 =6
| label5 =evaluate
| value5 =16.6
| color5 =9
| label6 =design
| value6 =16.6
| color6 =10
}}
</nowiki></pre>

* The parameter {{para|thumb}} specifies which side of the page the chart is floated to and defaults to <code>right</code>, as with image files. To make the chart appear on the ''left'' side of the page, specify {{para|thumb|left}}.
* The parameter {{para|caption}} specifies a string of text that appears on a line just before the legend.
* The parameter {{para|other}}, if specified, will cause an "Other" item to appear in the legend.
* Each {{para|label''N''}} is a string of text that appears in the legend entry for a slice. Omitting it will cause a legend entry to not be shown for that slice.
* Each {{para|value''N''}} is the percentage that the slice represents. Do ''not'' include the percent sign. Also note that it is shown in the legend as written (just after the label), without any rounding or other reformatting.
* Each {{para|color''N''}} is a CSS color code or name. If omitted, it will default to the following hues:
{{div col|colwidth=10em}}
# {{legend|#a6cee3|light blue}}
# {{legend|#1f78b4|strong blue}}
# {{legend|#b2df8a|light green}}
# {{legend|#33a02c|strong green}}
# {{legend|#fb9a99|fuchsia}}
# {{legend|#e31a1c|red}}
# {{legend|#fdbf6f|light orange}}
# {{legend|#ff7f00|strong orange}}
# {{legend|#cab2d6|light purple}}
# {{legend|#6a3d9a|strong purple}}
# {{legend|#ffff99|light yellow}}
# {{legend|#b15928|brown}}
{{div col end}}

=== Limitations ===
* The values need to be percentages.
* Google Chrome and Safari do not appear to anti-alias borders, so the lines are a bit jagged. (For Chrome, this issue seems to be resolved; tested with version 26.)
* No labels can be put on the slices themselves.
* Inherently, it is not possible to save a copy of the chart using the browser's "Save Image" function.
* Max. number of slices that can be displayed: '''30'''

=== How it works ===
{{Pie chart
|other = yes
|value1 = 42
|label1 = One
|value2 = 32
|label2 = Two
|value3 = 12
|label3 = Three
|value4 = 3
|label4 = Four
|value5 = 2
|label5 = Five
|value6 = 1
|label6 = Six
}}

This is an ''experimental'' template that draws pie charts using a single image, a lot of (inline) CSS code generated by parser functions, and ''absolutely no JavaScript''. It uses a technique for [http://erezsh.wordpress.com/2008/07/31/drawing-diagonal-lines-with-css/ drawing diagonal lines in CSS] exploiting the fact that borders set on elements are miter joined. Thus, it is possible to set one border to an opaque color, with the others fully transparent, to form a diagonal line. The angle of the line can be controlled by adjusting the widths of two adjacent borders (one of them opaque) relative to each other.

Pie slices are drawn in clockwise order in a counterclockwise direction. These pie slices are positioned:
* Below a [[:File:Circle frame.svg|200×200px image]] having a transparent circle on a light-colored background (same as the background color used for CSS class <code>thumbinner</code>)
* Inside a container element with <code>overflow: hidden;</code> set
This allows only the part of each slice that is inside the circle to be visible on the page.

Most of the code in {{tlx|Pie chart/slice}} is divided into five sections, the first four corresponding to quadrants of the circle and the last to cleanly cover the case in which one slice occupies 100% of the chart.
{{-}}

=== Example ===
{{Pie chart
| caption=Religion in the Czech Republic as of 2001.
| other = yes
| label1 = Atheists and agnostics
| value1 = 59
| color1 = silver
| label2 = Catholics
| value2 = 26.8
| color2 = #008
| label3 = Protestants
| value3 = 2.5
| color3 = #08f
}}
The following example of [[Template:Pie chart]] generates the pie chart shown at right. 
<pre style="overflow:auto">
{{Pie chart
| caption=Religion in the Czech Republic as of 2001.
| other = yes
| label1 = Atheists and agnostics
| value1 = 59
| color1 = silver
| label2 = Catholics
| value2 = 26.8
| color2 = #008
| label3 = Protestants
| value3 = 2.5
| color3 = #08f
}}
</pre>