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<A HREF="toc.html">Contents</A>
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<A HREF="7102Specifyingadatetimescalewithamanualcallback.html">Previous</A>
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<A HREF="712Addingarbitrarytextstringstothegraph.html">Next</A>
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<HR NOSHADE>
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<H2><A NAME="7_11">7.11 Adjusting labels on a text scale</A></H2>
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<P> In the following section we will work through an number of examples
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on how to manipulate labels on a text scale. Primarily we will
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investigate how to best handle the case where you have a large number
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of values.</P>
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<P> As a remainder; Text scale is meant to be used on the X-axis when
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the X-axis doesn't have a numeric value, i.e you are only interested in
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linear ordering of the data. If you don't specify the labels manually
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they will be set automatically starting from 1 as the example below
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shows.</P>
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<P><DIV class="example">
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<BR> <A href="exframes/frame_bartutex1.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/img/img/img/img/img/bartutex1.png" WIDTH="300"></A>
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<BR><B>Figure 83:</B> A simple bar plot using an automatic text scale <A href="exframes/frame_bartutex1.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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<P> To specify the labels on the X-axis as suitable text strings you
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call the method <A href="../ref/Axis.html#_AXIS_SETTICKLABELS">
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Axis::SetTickLabels()</A> with an array containing the text-labels. If
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there are more data points than labels the non-specified labels will be
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given their ordinal number. If we augment the previous example with the
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name of the month we get the following new example</P>
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<P><DIV class="example">
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<BR> <A href="exframes/frame_bartutex2.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/img/img/img/img/img/bartutex2.png" WIDTH="300"></A>
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<BR><B>Figure 84:</B> Manually specifying the text scale labels <A href="exframes/frame_bartutex2.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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<P></P>
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<HR> <SMALL><STRONG> Tip:</STRONG> To get hold of localized version of
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the month names (or weekdays) you can use the <A href="../ref/DateLocale.html#_C_DATELOCALE">
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DateLocal</A> class available in the global variable $gDateLocale If no
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locale has been specified the default locale for the installation will
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be used.</SMALL>
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<HR>
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<P> What happen now if we have a larger number of bars? Let's try with
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25 bars and see what result we get.</P>
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<P><DIV class="example">
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<BR> <A href="exframes/frame_bartutex3.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/img/img/img/img/img/bartutex3.png" WIDTH="300"></A>
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<BR><B>Figure 85:</B> A larger data set <A href="exframes/frame_bartutex3.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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<P> Not all to impressive. The labels are to close and they overlap.
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Hence it is not a good idea to display every label. To adjust what
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labels are to be displayed you use the <A href="../ref/Axis.html#_AXIS_SETTEXTLABELINTERVAL">
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SetTextLabelInterval()</A> method. The argument to this method is the
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interval between text labels. So to display only every 3 month you
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would add the line</P>
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<P><DIV class="phpscript"><CODE><FONT color="#000000"> <FONT color="#0000BB">
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$graph</FONT><FONT color="#007700">-></FONT><FONT color="#0000BB">xaxis</FONT><FONT
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color="#007700">-></FONT><FONT color="#0000BB">SetTextLabelIntervall</FONT><FONT
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color="#007700">(</FONT><FONT color="#0000BB">3</FONT><FONT color="#007700">
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)</FONT><FONT color="#0000BB"></FONT></FONT></CODE></DIV></P>
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<P></P>
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<P> Which would give the result shown below<DIV class="example">
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<BR> <A href="exframes/frame_bartutex4.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/img/img/img/img/img/bartutex4.png" WIDTH="300"></A>
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<BR><B>Figure 86:</B> Displaying only every third label <A href="exframes/frame_bartutex4.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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<P> Much better, quite readable.</P>
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<P> If we have an even larger data set it might not longer be meaningful
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to display all the tick marks since they would simple become to close.
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In JpGraph there is a possibility to specify that you only would like
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every<I> n</I>:th tick mark to be visible ( <A href="../ref/Axis.html#_AXIS_SETTEXTTICKINTERVAL">
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SetTextTickIntervall()</A> ). For bar graphs using text scale however,
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that might not be such a good idea since the tick marks are between the
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bars and the labels centered under the bars. If we only were to
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display, say, every 3 tick mark it wouldn't look to good. Not that we
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can't do it, as the example below shows, but it just doesn't look very
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good.<DIV class="example">
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<BR> <A href="exframes/frame_bartutex5.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/img/img/img/img/img/bartutex5.png" WIDTH="300"></A>
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<BR><B>Figure 87:</B> Displaying just every third tick mark. <A href="exframes/frame_bartutex5.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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<P> A better way to handle large data set is simply to hide the tick
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marks all together. Tick marks may be hidden by calling the method <A href="../ref/Axis.html#_AXIS_HIDETICKS">
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Axis::HideTicks(); <A> If we hide all the ticks on the X-axis we will
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get the result shown below<DIV class="example">
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<BR> <A href="exframes/frame_bartutex6.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/img/img/img/img/img/bartutex6.png" WIDTH="300"></A>
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<BR><B>Figure 88:</B> Hiding all tick mark. <A href="exframes/frame_bartutex6.html"
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target="blank">[src]</A>
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<P></P>
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</DIV></A></A></P>
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<P></P>
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<HR NOSHADE>
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<A HREF="toc.html">Contents</A>
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<A HREF="7102Specifyingadatetimescalewithamanualcallback.html">Previous</A>
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<A HREF="712Addingarbitrarytextstringstothegraph.html">Next</A>
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