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  28  <H2><A NAME="8_2">8.2 Pie plots</A></H2>
  29  <P> So far we have just show plots based on an X-Y coordinate system.
  30   This is not the only types of graphs you can create with JpGraph.
  31   Another common type is Pie plots. JpGraph supports both 2D and 3D pie
  32   plots. For 2D pie plots there are also 2 versions, but more on that
  33   later.</P>
  34  <P> The main difference as compared to the X-Y plots is that to all pie
  35   plots are added to the <A href="../ref/PieGraph.html#_C_PIEGRAPH">
  36   PieGraph()</A> instead of the Graph() object we used for the X-Y graphs
  37   we have drawn so far. For this you must first include the
  38   &quot;jpgraph_pie.php&quot; in your script (or &quot;jpgraph_pie3d.php&quot; if you want to
  39   use 3-dimensional pies).</P>
  40  <P> Below you cane see the code needed to create the simplest possible
  41   pie graph just using the default settings.</P>
  42  <P><DIV class="phpscript"><CODE><FONT color="#000000"> <FONT color="#0000BB">
  43  &nbsp;</FONT><FONT color="#007700">include&nbsp;(</FONT><FONT color="#DD0000">
  44  &quot;../jpgraph.php&quot;</FONT><FONT color="#007700">);
  45  <BR>include&nbsp;(</FONT><FONT color="#DD0000">&quot;../jpgraph_pie.php&quot;</FONT><FONT
  46  color="#007700">);
  47  <BR>
  48  <BR></FONT><FONT color="#0000BB">$data&nbsp;</FONT><FONT color="#007700">
  49  =&nbsp;array(</FONT><FONT color="#0000BB">40</FONT><FONT color="#007700">,</FONT><FONT
  50  color="#0000BB">60</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">
  51  21</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">33</FONT><FONT
  52  color="#007700">);
  53  <BR>
  54  <BR></FONT><FONT color="#0000BB">$graph&nbsp;</FONT><FONT color="#007700">
  55  =&nbsp;new&nbsp;</FONT><FONT color="#0000BB">PieGraph</FONT><FONT color="#007700">
  56  (</FONT><FONT color="#0000BB">300</FONT><FONT color="#007700">,</FONT><FONT
  57  color="#0000BB">200</FONT><FONT color="#007700">);
  58  <BR></FONT><FONT color="#0000BB">$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT
  59  color="#0000BB">SetShadow</FONT><FONT color="#007700">();
  60  <BR>
  61  <BR></FONT><FONT color="#0000BB">$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT
  62  color="#0000BB">title</FONT><FONT color="#007700">-&gt;</FONT><FONT color="#0000BB">
  63  Set</FONT><FONT color="#007700">(</FONT><FONT color="#DD0000">
  64  &quot;A&nbsp;simple&nbsp;Pie&nbsp;plot&quot;</FONT><FONT color="#007700">);
  65  <BR>
  66  <BR></FONT><FONT color="#0000BB">$p1&nbsp;</FONT><FONT color="#007700">=&nbsp;new&nbsp;</FONT><FONT
  67  color="#0000BB">PiePlot</FONT><FONT color="#007700">(</FONT><FONT color="#0000BB">
  68  $data</FONT><FONT color="#007700">);
  69  <BR></FONT><FONT color="#0000BB">$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT
  70  color="#0000BB">Add</FONT><FONT color="#007700">(</FONT><FONT color="#0000BB">
  71  $p1</FONT><FONT color="#007700">);
  72  <BR></FONT><FONT color="#0000BB">$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT
  73  color="#0000BB">Stroke</FONT><FONT color="#007700">();
  74  <BR></FONT><FONT color="#0000BB"></FONT></FONT></CODE></DIV></P>
  75  <P> The above code would give the following pie graph<DIV class="example">
  76  <BR> <A href="exframes/frame_example26.html" target="blank"><IMG border="0"
  77  HEIGHT="200"       src="img/img/img/img/img/img/example26.png" WIDTH="300"></A>
  78  <BR><B>Figure 121:</B> The simplest possible pie graph <A href="exframes/frame_example26.html"
  79  target="blank">[src]</A>&nbsp;
  80  <P></P>
  81  </DIV></P>
  82  <P> There is a few things worth noting here</P>
  83  <UL>
  84  <LI> By default all pie slices have the percentage shown just outside
  85   the slice.</LI>
  86  <LI> The colors are automatically assigned to the slices.</LI>
  87  <LI> The pie have the edges marked by default</LI>
  88  <LI> The first slice start at 0 degrees (3 o'clock)</LI>
  89  </UL>
  90  <P> You can change almost all aspects of appearance of the pie graphs.
  91   For example you could change :</P>
  92  <UL>
  93  <LI> Change the angle for the first slice, (<A href="../ref/PiePlot.html#_PIEPLOT_SETSTARTANGLE">
  94  PiePlot::SetStartAngle()</A>)</LI>
  95  <LI>Remove the border lines around the pie (<A href="../ref/PiePlot.html#_PIEPLOT_SHOWBORDER">
  96  PiePlot::ShowBorder()</A>)</LI>
  97  <LI>Change the color of the border (<A href="../ref/PiePlot.html#_PIEPLOT_SETCOLOR">
  98  PiePlot::SetColor()</A>,</LI>
  99  <LI>Change the colors of the slices (<A href="../ref/PiePlot.html#_PIEPLOT_SETSLICECOLORS">
 100  PiePlot::SetSliceCOlors()</A>)</LI>
 101  <LI> Change the size and position of the pie (<A href="../ref/PiePlot.html#_PIEPLOT_SETSIZE">
 102  PiePlot::SetSize()</A>, <A href="../ref/PiePlot.html#_PIEPLOT_SETCENTER">
 103  PiePlot::SetCenter()</A>)</LI>
 104  <LI> Adjust the labels for the slice (color, font, format, position ) by
 105   accessing the <A href="../ref/DisplayValue.html#_C_DISPLAYVALUE">value
 106   property</A> of pie plots, for example (<A href="../ref/DisplayValue.html#_DISPLAYVALUE_SETFONT">
 107  PiePlot::value::SetFont()</A>, You can read more about label formatting
 108   and how to change what is displayed as a value further down in this
 109   chapter.</LI>
 110  </UL>
 111  <P></P>
 112  <P> The next simplest addition we can do is to add a legend to the pie
 113   graph. We do this by using the <A href="../ref/PiePlot.html#_PIEPLOT_SETLEGENDS">
 114   SetLegends();</A> method. By adding the legends to the previous example
 115   we get the following image<DIV class="example">
 116  <BR> <A href="exframes/frame_example26.1.html" target="blank"><IMG border="0"
 117  HEIGHT="200"       src="img/img/img/img/img/img/example26.1.png" WIDTH="300"></A>
 118  <BR><B>Figure 122:</B> Adding a legend to the pie graph <A href="exframes/frame_example26.1.html"
 119  target="blank">[src]</A>&nbsp;
 120  <P></P>
 121  </DIV></P>
 122  <P></P>
 123  <P> (In the figure above we also moved the center of the pie slightly to
 124   the left to make more room for the legend box.)</P>
 125  <P> The text for the legends can also contain printf() style format
 126   strings to format a number. This number passed on into this string is
 127   either the absolute value of the slice or the percentage value. How to
 128   switch between the is describe further down in this chapter.</P>
 129  <P> The next change you might want to change is the size and position of
 130   the Pie plot. You can change the size with a call to <A href="../ref/PiePlot.html#_PIEPLOT_SETSIZE">
 131   SetSize();</A> and the position of the center of the pie plot with a
 132   call to <A href="../ref/PiePlot.html#_PIEPLOT_SETCENTER"> SetCenter();</A>
 133   The size can be specified as either an absolute size in pixels or as a
 134   fraction of width/height (whatever is the smallest). The position of
 135   the pie plot is specified as a fraction of the width and height.</P>
 136  <P> To put the size and positioning API to use we will show how to put
 137   several pie plots on the same pie graph. In the following example we
 138   have also adjusted the legends of the slice values to use a smaller
 139   font.</P>
 140  <P> What we do in this example is quite simple, create 4 pie plots, make
 141   them smaller and put them in the four corner of the graph. This will
 142   give the result as shown in the following example.<DIV class="example">
 143  <BR> <A href="exframes/frame_pieex3.html" target="blank"><IMG border="0" HEIGHT="300"
 144        src="img/img/img/img/img/img/pieex3.png" WIDTH="350"></A>
 145  <BR><B>Figure 123:</B> Multiple pie plots in the same pie graph <A href="exframes/frame_pieex3.html"
 146  target="blank">[src]</A>&nbsp;
 147  <P></P>
 148  </DIV></P>
 149  <P></P>
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