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<A HREF="toc.html">Contents</A>
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<HR NOSHADE>
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<H2><A NAME="8_20">8.20 Adjusting the auto-scaling limits - grace value</A>
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</H2>
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<P> By default the auto-scaling algorithm tries to make best possible
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use of screen estate by making the scale as large as possible, i.e. the
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extreme values (min/max) will be on the top and bottom of the scale if
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they happen to fall on a scale-tick. So for example doing a simple line
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plot could look like the plot shown in the below.<DIV class="example">
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<BR> <A href="exframes/frame_example3.2.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/example3.2.png" WIDTH="300"></A>
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<BR><B>Figure 96:</B> A typical graph with autoscaling and grace=0 <A href="exframes/frame_example3.2.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> However you might sometime want to add some extra to the minimum and
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maximum values so that there is some "air" in the graph between the end
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of the scale values and the extreme points in the graphs. This can be
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done by adding a "grace" percentage to the scale. So for example adding
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10% to the y-scale in the image above is done by calling the <A href="../ref/LinearScale.html#_LINEARSCALE_SETGRACE">
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SetGrace()</A> method on the yscale as in</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">yaxis</FONT><FONT
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color="#007700">-></FONT><FONT color="#0000BB">scale</FONT><FONT color="#007700">
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-></FONT><FONT color="#0000BB">SetGrace</FONT><FONT color="#007700">(</FONT><FONT
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color="#0000BB">10</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">
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10</FONT><FONT color="#007700">);</FONT><FONT color="#0000BB"></FONT></FONT>
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</CODE></DIV></P>
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<P> These lines add a minimum of 10% to the top and bottom values of the
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scale. Note that we say "minimum" since depending on the specific tick
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values choose this might be a little bit more to make the end of the
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scale fall on an even tick mark.</P>
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<P> Adding this line to the previous graph will result in the following
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example</P>
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<P><DIV class="example">
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<BR> <A href="exframes/frame_example3.2.1.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/example3.2.1.png" WIDTH="300"></A>
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<BR><B>Figure 97:</B> Adding 10% grace value to top and bottom of the
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Y-scale <A href="exframes/frame_example3.2.1.html" target="blank">[src]</A>
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<P></P>
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</DIV></P>
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<P> Since we haven't adjusted the position of the X-axis it will remain
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at Y=0 which might not necessary be what we would like so we therefor
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also 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">SetPos</FONT><FONT color="#007700">
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(</FONT><FONT color="#DD0000">"min"</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> So that the X-axis always will remain at the lowest possible
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Y-value. Doing this will then result in the example below</P>
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<P><DIV class="example">
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<BR> <A href="exframes/frame_example3.2.2.html" target="blank"><IMG border="0"
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HEIGHT="200" src="img/example3.2.2.png" WIDTH="300"></A>
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<BR><B>Figure 98:</B> Using grace but also adjusting the position of the
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X-axis <A href="exframes/frame_example3.2.2.html" 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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