PLOT LEGENDS PACKAGE TUTORIAL
"Plot Legends" Package
There are two ways to use the functions in this package to place a legend in a graphic: the first can only be used as an option to the built-in functions Plot, ListPlot, and ListLinePlot, while the second can be applied to any graphic. To use the PlotLegend option, you simply specify the text for each curve. If there are more curves than text, the text is used cyclically. The second way of placing a legend in a graphic is to use ShowLegend. With ShowLegend you specify the graphic and legend as arguments.
| PlotLegend->{text1,text2,...} | option for Plot to place a legend with text for each curve |
| ShowLegend[graphic,legend1,legend2,...] | place the  in the given graphic |
Methods for placing a legend in a graphic.
Here are sine and cosine curves with a legend.
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Here are list plots with a legend.
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{{{ , },... },opts} | specification of a legend, with color primitives or graphics for the  and expression suitable for placement in Text primitives in the  |
| {colorfunction,n,minstring,maxstring,opts} | specification of a legend with n boxes, each colored with the colorfunction with optional strings placed by the end |
Legend formats for ShowLegend.
Here is a density plot with a legend.
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Here is a surface plot with a legend.
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Plot with a legend for the filling styles.
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Options for use with legends.
There are various options that can be used to control the shape and characteristics of a legend. The most important of these is LegendPosition, which places the lower-left corner of a legend box in a position specified by a coordinate system scaled so the center of the graphic is at 
, and the longest side of the graphic runs from 
to 
. This same coordinate system is used for LegendSize and LegendShadow.
More options for use with legends.
Several of the options that determine the amount of blank space around the various elements of a legend accept a number that is the ratio of the size of the space desired to the size of one of the key boxes—the colored boxes that denote a key in the legend. These options include LegendSpacing, LegendTextSpace, LegendLabelSpace, and LegendBorderSpace.
This example uses many of the options for legends.
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| Legend[legendargs,opts] | give the graphics primitives that describe an individual legend |
| ShadowBox[pos,size,opts] | give the graphics primitives for a box with a drop shadow |
Legend functions that do not display a graphic.
The arguments for Legend are the same as those inside the first set of braces in the description of a legend given in ShowLegend. Using Legend or ShadowBox, you can generate just the graphics primitives of a legend or box with a drop shadow to be used elsewhere in your own graphics.
This represents a box with a shadow.
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Here is what the box looks like.
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Options for ShadowBox.
dimensions in the same coordinate system as LegendPosition
gives an offset for the drop shadow
or 
determines the orientation of the boxes
and 
offset of the shadow from the box