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  27  <HR NOSHADE>
  28  <H2><A NAME="8_11">8.11 Adjusting labels on a text scale</A></H2>
  29  <P> In the following section we will work through an number of examples
  30   on how to manipulate labels on a text scale. Primarily we will
  31   investigate how to best handle the case where you have a large number
  32   of values.</P>
  33  <P> As a remainder; Text scale is meant to be used on the X-axis when
  34   the X-axis doesn't have a numeric value, i.e you are only interested in
  35   linear ordering of the data. If you don't specify the labels manually
  36   they will be set automatically starting from 1 as the example below
  37   shows.</P>
  38  <P><DIV class="example">
  39  <BR> <A href="exframes/frame_bartutex1.html" target="blank"><IMG border="0"
  40  HEIGHT="200"  src="img/bartutex1.png" WIDTH="300"></A>
  41  <BR><B>Figure 79:</B> A simple bar plot using an automatic text scale <A href="exframes/frame_bartutex1.html"
  42  target="blank">[src]</A>&nbsp;
  43  <P></P>
  44  </DIV></P>
  45  <P></P>
  46  <P> To specify the labels on the X-axis as suitable text strings you
  47   call the method <A href="../ref/Axis.html#_AXIS_SETTICKLABELS">
  48   Axis::SetTickLabels()</A> with an array containing the text-labels. If
  49   there are more data points than labels the non-specified labels will be
  50   given their ordinal number. If we augment the previous example with the
  51   name of the month we get the following new example</P>
  52  <P><DIV class="example">
  53  <BR> <A href="exframes/frame_bartutex2.html" target="blank"><IMG border="0"
  54  HEIGHT="200"  src="img/bartutex2.png" WIDTH="300"></A>
  55  <BR><B>Figure 80:</B> Manually specifying the text scale labels <A href="exframes/frame_bartutex2.html"
  56  target="blank">[src]</A>&nbsp;
  57  <P></P>
  58  </DIV></P>
  59  <P></P>
  60  <P></P>
  61  <HR> <SMALL><STRONG> Tip:</STRONG> To get hold of localized version of
  62   the month names (or weekdays) you can use the <A href="../ref/DateLocale.html#_C_DATELOCALE">
  63   DateLocal</A> class available in the global variable $gDateLocale If no
  64   locale has been specified the default locale for the installation will
  65   be used.</SMALL>
  66  <HR>
  67  <P> What happen now if we have a larger number of bars? Let's try with
  68   25 bars and see what result we get.</P>
  69  <P><DIV class="example">
  70  <BR> <A href="exframes/frame_bartutex3.html" target="blank"><IMG border="0"
  71  HEIGHT="200"  src="img/bartutex3.png" WIDTH="300"></A>
  72  <BR><B>Figure 81:</B> A larger data set <A href="exframes/frame_bartutex3.html"
  73  target="blank">[src]</A>&nbsp;
  74  <P></P>
  75  </DIV></P>
  76  <P></P>
  77  <P> Not all to impressive. The labels are to close and they overlap.
  78   Hence it is not a good idea to display every label. To adjust what
  79   labels are to be displayed you use the <A href="../ref/Axis.html#_AXIS_SETTEXTLABELINTERVAL">
  80   SetTextLabelInterval()</A> method. The argument to this method is the
  81   interval between text labels. So to display only every 3 month you
  82   would add the line</P>
  83  <P><DIV class="phpscript"><CODE><FONT color="#000000"> <FONT color="#0000BB">
  84  &nbsp;$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT color="#0000BB">xaxis</FONT><FONT
  85  color="#007700">-&gt;</FONT><FONT color="#0000BB">SetTextLabelIntervall</FONT><FONT
  86  color="#007700">(</FONT><FONT color="#0000BB">3</FONT><FONT color="#007700">
  87  )</FONT><FONT color="#0000BB"></FONT></FONT></CODE></DIV></P>
  88  <P></P>
  89  <P> Which would give the result shown below<DIV class="example">
  90  <BR> <A href="exframes/frame_bartutex4.html" target="blank"><IMG border="0"
  91  HEIGHT="200"  src="img/bartutex4.png" WIDTH="300"></A>
  92  <BR><B>Figure 82:</B> Displaying only every third label <A href="exframes/frame_bartutex4.html"
  93  target="blank">[src]</A>&nbsp;
  94  <P></P>
  95  </DIV></P>
  96  <P></P>
  97  <P> Much better, quite readable.</P>
  98  <P> If we have an even larger data set it might not longer be meaningful
  99   to display all the tick marks since they would simple become to close.
 100   In JpGraph there is a possibility to specify that you only would like
 101   every<I> n</I>:th tick mark to be visible ( <A href="../ref/Axis.html#_AXIS_SETTEXTTICKINTERVAL">
 102   SetTextTickIntervall()</A> ). For bar graphs using text scale however,
 103   that might not be such a good idea since the tick marks are between the
 104   bars and the labels centered under the bars. If we only were to
 105   display, say, every 3 tick mark it wouldn't look to good. Not that we
 106   can't do it, as the example below shows, but it just doesn't look very
 107   good.<DIV class="example">
 108  <BR> <A href="exframes/frame_bartutex5.html" target="blank"><IMG border="0"
 109  HEIGHT="200"  src="img/bartutex5.png" WIDTH="300"></A>
 110  <BR><B>Figure 83:</B> Displaying just every third tick mark. <A href="exframes/frame_bartutex5.html"
 111  target="blank">[src]</A>&nbsp;
 112  <P></P>
 113  </DIV></P>
 114  <P></P>
 115  <P> A better way to handle large data set is simply to hide the tick
 116   marks all together. Tick marks may be hidden by calling the method <A href="../ref/Axis.html#_AXIS_HIDETICKS">
 117   Axis::HideTicks(); <A> If we hide all the ticks on the X-axis we will
 118   get the result shown below<DIV class="example">
 119  <BR> <A href="exframes/frame_bartutex6.html" target="blank"><IMG border="0"
 120  HEIGHT="200"  src="img/bartutex6.png" WIDTH="300"></A>
 121  <BR><B>Figure 84:</B> Hiding all tick mark. <A href="exframes/frame_bartutex6.html"
 122  target="blank">[src]</A>&nbsp;
 123  <P></P>
 124  </DIV></A></A></P>
 125  <P></P>
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