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<H3><A NAME="8_1_5">8.1.5 Adding a legend to the graph</A></H3>
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<P> With more than one plot on the same graph it is necessary to somehow
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indicate which plot is which. This is normally done by adding a legend
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to the graph.</P>
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<P> You will see that each plot type has a 'SetLegend()' method which is
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used to name that plot in the legend. SO to name the two plots in the
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example we have been working with so far we need to add the lines<DIV class="phpscript">
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<CODE><FONT color="#000000"> <FONT color="#0000BB"> $lineplot</FONT><FONT
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color="#007700">-></FONT><FONT color="#0000BB">SetLegend</FONT><FONT color="#007700">
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(</FONT><FONT color="#DD0000">"Plot 1"</FONT><FONT color="#007700">);
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<BR></FONT><FONT color="#0000BB">$lineplot2</FONT><FONT color="#007700">
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-></FONT><FONT color="#0000BB">SetLegend</FONT><FONT color="#007700">(</FONT><FONT
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color="#DD0000">"Plot 2"</FONT><FONT color="#007700">);</FONT><FONT color="#0000BB">
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</FONT></FONT></CODE></DIV></P>
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<P> to the previous code. The resulting graph is shown below
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<!--?
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Example('example5.1','Adding a legend to the graph');
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?-->
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As you can see the legend gets automatically sized depending on how
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many plots there are that have legend texts to display. By default it
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is placed with it's top right corner close to the upper right edge of
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the image. Depending on the image you might want to adjust this or you
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might want to add a larger margin which is big enough to accompany the
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legend. Let's do both.</P>
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<P> First we increase the right margin and then we place the legend so
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that it is roughly centered. We will also enlarge the overall image so
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the plot area doesn't get too squeezed.</P>
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<P> To modify the legend you access the 'legend' property of the graph.
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For a full reference on all the possibilities (changing colors, layout,
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etc) see <A href="../ref/Legend.html#_C_LEGEND/">class legend</A> in
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the class reference</P>
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<P> For this we use the legends 'SetPos()' method as in<DIV class="phpscript">
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<CODE><FONT color="#000000"> <FONT color="#0000BB"> $graph</FONT><FONT color="#007700">
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-></FONT><FONT color="#0000BB">legend</FONT><FONT color="#007700">-></FONT><FONT
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color="#0000BB">Pos</FONT><FONT color="#007700">(</FONT><FONT color="#0000BB">
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0.05</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">0.5</FONT><FONT
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color="#007700">,</FONT><FONT color="#DD0000">"right"</FONT><FONT color="#007700">
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,</FONT><FONT color="#DD0000">"center"</FONT><FONT color="#007700">);</FONT><FONT
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color="#0000BB"></FONT></FONT></CODE></DIV></P>
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<P></P>
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<P> Doing this small modification will give the result shown below<DIV class="example">
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<BR> <A href="exframes/frame_example6.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/example6.png" WIDTH="400"></A>
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<BR><B>Figure 11:</B> Adjusting the layout to give more rooms for the
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legend <A href="exframes/frame_example6.html" target="blank">[src]</A>
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<P></P>
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</DIV></P>
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<P> The above method 'SetPos()' deserves some explanation since it might
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not be obvious. You specify the position as a fraction of the overall
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width and height of the entire image. This makes it possible for you to
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resize the image within disturbing the relative position of the legend.
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We will later see that the same method is just to place arbitrary text
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in the image.</P>
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<P> To give added flexibility one must also specify to what edge of the
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legend the position given should be relative to. In the example above
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we have specified "right" edge on the legend for the for the horizontal
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positioning and "center" for the vertical position.</P>
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<P> This means that the right edge of the legend should be position 5 %
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of the image width from the right. If you had specified "left" the the
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legends left edge would be positioned 5 % of the image width from the
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image left side.</P>
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<P> By default the legends in the legend box gets stacked on top of each
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other. The other possibility is to have them sideways. To adjust this
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you use the <A href="../ref/Legend.html#_LEGEND_SETLAYOUT">SetLayout()</A>
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method. Using a horizontal layout with the previous example give the
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following result.<DIV class="example">
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<BR> <A href="exframes/frame_example6.1.html" target="blank"><IMG border="0"
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HEIGHT="240" src="img/example6.1.png" WIDTH="300"></A>
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<BR><B>Figure 12:</B> Using a horizontal layout for the legends <A href="exframes/frame_example6.1.html"
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target="blank">[src]</A>
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<P></P>
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</DIV></P>
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<P></P>
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<H4>8.1.5.1 Adjusting the layout of the legend</H4>
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<P> For more advanced fomatting of the legend it is possible to adjust</P>
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<UL>
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<LI> The number of columns in the legend</LI>
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<LI> Specify vertical / horizontal margins for legend columns</LI>
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</UL>
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<P> In order to adjust the number of columns used in the legend the
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method<I> Legend::SetColumns</I> is used. So for example to have the
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legend lined up using three columns the follwing lines have to be added
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to teh script<DIV class="phpscript"><CODE><FONT color="#000000"> <FONT color="#0000BB">
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$graph</FONT><FONT color="#007700">-></FONT><FONT color="#0000BB">
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legend</FONT><FONT color="#007700">-></FONT><FONT color="#0000BB">
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SetColumns</FONT><FONT color="#007700">(</FONT><FONT color="#0000BB">3</FONT><FONT
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color="#007700">);</FONT><FONT color="#0000BB"></FONT></FONT></CODE></DIV>
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</P>
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<P></P>
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