ch14s08.html
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Adjusting the appearance of the scale labels</title><link rel="stylesheet" type="text/css" href="manual.css"><meta name="generator" content="DocBook XSL Stylesheets V1.76.0"><link rel="home" href="index.html" title="JpGraph Manual"><link rel="up" href="ch14.html" title="Chapter 14. Common features for all Cartesian (x,y) graph types"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Adjusting the appearance of the scale labels</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center">Chapter 14. Common features for all Cartesian (x,y) graph types</th><td width="20%" align="right"> </td></tr></table><hr></div><div class="sect1" title="Adjusting the appearance of the scale labels"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="sec1.adv-scale-label-handling"></a>Adjusting the appearance of the scale labels</h2></div></div></div>
<p>Since scale labels play such an important part of producing a visually pleasing
graph there are a number of ways to fine tune this appearance. In the section below
we have tried to logically group the different options to make it easier to get an
overview.</p>
<p></p>
<div class="sect2" title="Adjusting the position"><div class="titlepage"><div><div><h3 class="title"><a name="id2546048"></a>Adjusting the position</h3></div></div></div>
<p>The exact position of the labels can be adjusted with the methods</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::SetLabelAlign($aHAlign,$aVAlign='top',$aParagraphAlign='left')</code></p>
<p>With this method the anchor point for the labels can be adjusted.
The labels are positioned straight below (or on the side for
vertical axis) the corresponding tick mark and by adjusting the
anchor point in the label different effect can be achieved. By
default labels on the x-axis there anchor point on the top side in
the center. For y-axis (on the left) the anchor point is middle of
the right edge of the label.</p>
</li><li class="listitem">
<p><code class="code">Axis::SetLabelMargin($aMargin)</code></p>
<p>This method adjusts the distance between the corresponding tick
mark and the label it self.</p>
</li><li class="listitem">
<p><code class="code">Axis::SetLabelSide($aSidePos)</code></p>
<p>This method will adjust on what side the labels will be
positioned. For a horizontal axis it cna be either above or below
the axis and for a vertical axis it can be on the left or right
side. The position is defined by one of the following
self-explaining defines</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="circle"><li class="listitem">
<p><code class="code">SIDE_LEFT</code></p>
</li><li class="listitem">
<p><code class="code">SIDE_RIGHT</code></p>
</li><li class="listitem">
<p><code class="code">SIDE_TOP</code></p>
</li><li class="listitem">
<p><code class="code">SIDE_BOTTOM</code></p>
</li></ul></div><p>
</p>
</li></ul></div><p>
</p>
</div>
<div class="sect2" title="Adjusting font and color"><div class="titlepage"><div><div><h3 class="title"><a name="id2546113"></a>Adjusting font and color</h3></div></div></div>
<p>By default the color of the labels will be the same as for the axis but it is
possible to use a different color for the labels by supplying a second argument
to the <code class="code">SetColor()</code> method for the axis.</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::SetColor($aColor,$aLabelColor=false) </code></p>
<p>There is actually a special twist to the color specification here.
If the color is specified as a single value this color value will be
used for all labels. However, if the color is specified with an
array then those colors will be used for the labels in turn. If
there are more labels then colors specified then the colors will be
used in a wrap around fashion.</p>
</li></ul></div><p>
</p>
<p>The font family for the labels can be specified with</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::SetFont($aFamily,$aStyle=FS_NORMAL,$aSize=10)</code></p>
</li></ul></div><p>
</p>
<p>By default a bitmap font is used for the labels (since those are the only
fonts guaranteed to be available everywhere)</p>
<p>
</p><div class="example"><a name="id2546229"></a><p class="title"><b>Example 14.1. Adjusting the axis font and color</b></p><div class="example-contents">
<div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$graph->xaxis->SetFont(FF_ARIAL,FS_NORMAL,9);
$graph->xaxis->SetColor('black','blue');</span></pre></td></tr></table></div>
</div></div><p><br class="example-break">
</p>
</div>
<div class="sect2" title="Adjusting the background of the labels"><div class="titlepage"><div><div><h3 class="title"><a name="id2546240"></a>Adjusting the background of the labels</h3></div></div></div>
<p>As a kind of a very special formatting it is also possible to set a specific
background for just the labels on the graph. This is most often used when there
is background image that risks of hiding the clarity of the labels. In those
cases it can be suitable to have a some lighter background to make it easier to
read the labels. </p>
<p>
</p><div class="tip" title="Tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3>
<p>This feature can also come in handy when using the more advanced
feature of combining several graphs to amke the labels stand out.</p>
</div><p>
</p>
<p>The method that controls this is</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">SetAxisLabelBackground($aType,$aXFColor='lightgray',$aXColor='black',$aYFColor='lightgray',$aYColor='black')</code></p>
<p>Possible values of the type of background are:</p>
<p>
</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<p><code class="code">LABELBKG_NONE</code></p>
</li><li class="listitem">
<p><code class="code">LABELBKG_XAXIS</code></p>
</li><li class="listitem">
<p><code class="code">LABELBKG_YAXIS</code></p>
</li><li class="listitem">
<p><code class="code">LABELBKG_XAXISFULL</code></p>
</li><li class="listitem">
<p><code class="code">LABELBKG_YAXISFULL</code></p>
</li><li class="listitem">
<p><code class="code">LABELBKG_XY</code></p>
</li><li class="listitem">
<p><code class="code">LABELBKG_XYFULL</code></p>
</li></ol></div><p>
</p>
</li></ul></div><p>
</p>
<p>The way these possible background types works is best described by viewing the
example figures below</p>
<p>
</p><div class="informaltable">
<table border="0"><colgroup><col class="c1"><col class="c2"><col class="c3"></colgroup><tbody><tr><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex01"></a><p class="title"><b>Figure 14.25. <code class="code">LABELBKG_NONE</code> <code class="uri"><a class="uri" href="example_src/axislabelbkgex01.html" target="_top">(<code class="filename">axislabelbkgex01.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex01.png" alt="LABELBKG_NONE (axislabelbkgex01.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex02"></a><p class="title"><b>Figure 14.26. LABELBKG_XAXIS <code class="uri"><a class="uri" href="example_src/axislabelbkgex02.html" target="_top">(<code class="filename">axislabelbkgex02.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex02.png" alt="LABELBKG_XAXIS (axislabelbkgex02.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex03"></a><p class="title"><b>Figure 14.27. LABELBKG_YAXIS <code class="uri"><a class="uri" href="example_src/axislabelbkgex03.html" target="_top">(<code class="filename">axislabelbkgex03.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex03.png" alt="LABELBKG_YAXIS (axislabelbkgex03.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr><tr><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex04"></a><p class="title"><b>Figure 14.28. LABELBKG_YAXISFULL <code class="uri"><a class="uri" href="example_src/axislabelbkgex04.html" target="_top">(<code class="filename">axislabelbkgex04.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex04.png" alt="LABELBKG_YAXISFULL (axislabelbkgex04.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex05"></a><p class="title"><b>Figure 14.29. LABELBKG_XAXISFULL <code class="uri"><a class="uri" href="example_src/axislabelbkgex05.html" target="_top">(<code class="filename">axislabelbkgex05.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex05.png" alt="LABELBKG_XAXISFULL (axislabelbkgex05.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex06"></a><p class="title"><b>Figure 14.30. LABELBKG_XYFULL <code class="uri"><a class="uri" href="example_src/axislabelbkgex06.html" target="_top">(<code class="filename">axislabelbkgex06.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex06.png" alt="LABELBKG_XYFULL (axislabelbkgex06.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr><tr><td>
<p>
</p><div class="figure"><a name="fig.axislabelbkgex07"></a><p class="title"><b>Figure 14.31. LABELBKG_XY <code class="uri"><a class="uri" href="example_src/axislabelbkgex07.html" target="_top">(<code class="filename">axislabelbkgex07.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/axislabelbkgex07.png" alt="LABELBKG_XY (axislabelbkgex07.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td> </td><td> </td></tr></tbody></table>
</div><p>
</p>
</div>
<div class="sect2" title="Hiding and rotating labels"><div class="titlepage"><div><div><h3 class="title"><a name="id2546732"></a>Hiding and rotating labels</h3></div></div></div>
<p>For the x-axis it is common to rotate the label to better fit long text
labels. This is done with a call to</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::SetLabelAngle($aAngle)</code></p>
<p>Remember that in order to set an arbitrary angel on the labels the
font family must be one of the TTF font families. Bitmap fonts only
support horizontal and vertical rotation.</p>
</li></ul></div><p>
</p>
<p>There are actually five variant for hiding the aaxis</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::HideLabels($aHide=true)</code></p>
<p>This will hide all the labels on the axis</p>
</li><li class="listitem">
<p><code class="code">Axis::HideFirstLastLabels($aHide=true)</code></p>
<p>Will hide the first and last label</p>
</li><li class="listitem">
<p><code class="code">Axis::HideFirstLabels($aHide=true)</code></p>
<p>Will hide the first label</p>
</li><li class="listitem">
<p><code class="code">Axis::HideLastLabels($aHide=true)</code></p>
<p>Will hide the last label</p>
</li><li class="listitem">
<p><code class="code">Axis::HideZeroLabel($aHide=true)</code></p>
<p>This will avoid printing a "0.00" label. This can be useful when
the axis are set to be crossing at the origin. This was for example
used in <a class="xref" href="ch14.html#fig.funcex2" title="Figure 14.5. Example of AXSTYLE_BOXIN axis style (funcex2.php)">Figure 14.5. Example of <code class="code">AXSTYLE_BOXIN</code> axis style <code class="uri"><a class="uri" href="example_src/funcex2.html" target="_top">(<code class="filename">funcex2.php</code>)</a></code> </a></p>
</li></ul></div><p>
</p>
</div>
<div class="sect2" title="Fine tuning the automatic scales"><div class="titlepage"><div><div><h3 class="title"><a name="id2546838"></a>Fine tuning the automatic scales</h3></div></div></div>
<p>By default the auto-scaling algorithm tries ot find as tight upper and lower
bands as possible as long as they are even multiple of the chosen major step
size. In some instances some more space is needed. For example to have extra
room at the top of the graph to show data labels. In order to have some extra
space the method </p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">LinearScale::SetGrace($aGraceTop,$aGraceBottom=0)</code></p>
</li></ul></div><p>
</p>
<p>should be used. This method will adjust the autos calling algorithm by adding
the specified extra "grace"at the minimum and maximum value of the scale. The
grace value is specified as an integer [0,100] and specifies a percentage to add
to the min and max value before the auto scaling is made. Depending on the scale
step and overall scale several scale values might give the same resulting scale.
For example</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$graph->yscale->scale->SetGrace(20,20);</span></pre></td></tr></table></div><p>
</p>
<p>will add 20% extra values on the top and bottom values of the data series
before the auto scale is determined. The following four examples shows how this
can be used in practice. In <a class="xref" href="ch14s08.html#fig.grace_ex0" title="Figure 14.32. The original graph (grace_ex0.php)">Figure 14.32. The original graph <code class="uri"><a class="uri" href="example_src/grace_ex0.html" target="_top">(<code class="filename">grace_ex0.php</code>)</a></code> </a> a bar graph
without grace value is created. As can be seen since the scale is very tight the
labels of the individual bars are almost out of the graph plot area. In the
following three plots results of using different values for grace are
shown.</p>
<p>
</p><div class="informaltable">
<table border="0"><colgroup><col class="c1"><col class="c2"></colgroup><tbody><tr><td>
<p>
</p><div class="figure"><a name="fig.grace_ex0"></a><p class="title"><b>Figure 14.32. The original graph <code class="uri"><a class="uri" href="example_src/grace_ex0.html" target="_top">(<code class="filename">grace_ex0.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/grace_ex0.png" alt="The original graph (grace_ex0.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.grace_ex1"></a><p class="title"><b>Figure 14.33. Using a 10% grace <code class="uri"><a class="uri" href="example_src/grace_ex1.html" target="_top">(<code class="filename">grace_ex1.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/grace_ex1.png" alt="Using a 10% grace (grace_ex1.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr><tr><td>
<p>
</p><div class="figure"><a name="fig.grace_ex2"></a><p class="title"><b>Figure 14.34. Using a 50% grace <code class="uri"><a class="uri" href="example_src/grace_ex2.html" target="_top">(<code class="filename">grace_ex2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/grace_ex2.png" alt="Using a 50% grace (grace_ex2.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.grace_ex3"></a><p class="title"><b>Figure 14.35. Using a 100% grace <code class="uri"><a class="uri" href="example_src/grace_ex3.html" target="_top">(<code class="filename">grace_ex3.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/grace_ex3.png" alt="Using a 100% grace (grace_ex3.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr></tbody></table>
</div><p>
</p>
<p>We finish this section by noting that adding a large grace value might
sometimes make it necessary to move one or both of the axis manually. To explain
this we start with the graph in <a class="xref" href="ch14s08.html#fig.example3.2" title="Figure 14.36. The original line graph (example3.2.php)">Figure 14.36. The original line graph <code class="uri"><a class="uri" href="example_src/example3.2.html" target="_top">(<code class="filename">example3.2.php</code>)</a></code> </a></p>
<p>
</p><div class="figure"><a name="fig.example3.2"></a><p class="title"><b>Figure 14.36. The original line graph <code class="uri"><a class="uri" href="example_src/example3.2.html" target="_top">(<code class="filename">example3.2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/example3.2.png" alt="The original line graph (example3.2.php)"></span> </div></div><p><br class="figure-break">
</p>
<p>as can be seen the added plot marks (see ??) are outside the boundary of the
plot area and to solve this problem we add the line</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$graph->yaxis->scale->SetGrace( 10 , 10 );</span></pre></td></tr></table></div><p>
</p>
<p>to the script. This now gives the result shown in <a class="xref" href="ch14s08.html#fig.example3.2.1" title="Figure 14.37. Adding grace values. Note x-axis position at y=0 (example3.2.1.php)">Figure 14.37. Adding grace values. Note x-axis position at y=0 <code class="uri"><a class="uri" href="example_src/example3.2.1.html" target="_top">(<code class="filename">example3.2.1.php</code>)</a></code> </a></p>
<p>
</p><div class="figure"><a name="fig.example3.2.1"></a><p class="title"><b>Figure 14.37. Adding grace values. Note x-axis position at y=0 <code class="uri"><a class="uri" href="example_src/example3.2.1.html" target="_top">(<code class="filename">example3.2.1.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/example3.2.1.png" alt="Adding grace values. Note x-axis position at y=0 (example3.2.1.php)"></span> </div></div><p><br class="figure-break">
</p>
<p>The problem is now apparent. Since the x-axis is placed at y=0 by default the
x-axis is no longer at the bottom of the plot as was probably the intention. To
remedy this situation we have to manually place the x-axis at the minimum
y-scale position. This is done by adding the line</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">$graph->xaxis->SetPos( 'min' );</span></pre></td></tr></table></div><p>
</p>
<p>to the previous script. Doing this gives us back the wanted position of the
x-axis as shown in <a class="xref" href="ch14s08.html#fig.example3.2.2" title="Figure 14.38. Adjusting the position of the x-axis manually (example3.2.2.php)">Figure 14.38. Adjusting the position of the x-axis manually <code class="uri"><a class="uri" href="example_src/example3.2.2.html" target="_top">(<code class="filename">example3.2.2.php</code>)</a></code> </a></p>
<p>
</p><div class="figure"><a name="fig.example3.2.2"></a><p class="title"><b>Figure 14.38. Adjusting the position of the x-axis manually <code class="uri"><a class="uri" href="example_src/example3.2.2.html" target="_top">(<code class="filename">example3.2.2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/example3.2.2.png" alt="Adjusting the position of the x-axis manually (example3.2.2.php)"></span> </div></div><p><br class="figure-break">
</p>
</div>
<div class="sect2" title="Manually altering the appearance of tick marks"><div class="titlepage"><div><div><h3 class="title"><a name="id2547269"></a>Manually altering the appearance of tick marks</h3></div></div></div>
<p>To adjust the appearance of the tick marks the following three methods can be
used</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::SetTickSide($aSide)</code></p>
<p>For x-axis this specifies if the tick should be drawn above or
below the axis and for the y-axis it specifies if the tick marks
should be on the left or on the right of the axis. Possible values
of the side parameter are one of the following defines</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="circle"><li class="listitem">
<p><code class="code">SIDE_LEFT</code></p>
</li><li class="listitem">
<p><code class="code">SIDE_RIGHT</code></p>
</li><li class="listitem">
<p><code class="code">SIDE_TOP</code></p>
</li><li class="listitem">
<p><code class="code">SIDE_BOTTOM</code></p>
</li></ul></div><p>
</p>
</li><li class="listitem">
<p><code class="code">Axis::HideTicks($aHideMinor=true,$aHideMajor=true)</code></p>
<p>Calling this method will make it possible to hide either noe of or
both the minor or the major tick marks.</p>
</li><li class="listitem">
<p><code class="code">Axis::SetTickSize($aMajSize,$aMinSize=3)</code></p>
<p>This specifies the size (in pixels) of the major and minor tick
marks.</p>
</li></ul></div><p>
</p>
</div>
<div class="sect2" title="Manually specifying scale labels"><div class="titlepage"><div><div><h3 class="title"><a name="sec2.manually-spec-labels"></a>Manually specifying scale labels</h3></div></div></div>
<p>As was mentioned before it is perfectly possible to manually specify the scale
labels. This is normally done for "text" scales that are most commonly used with
bar graphs. </p>
<p>Specifying a text scale for the axis (normally the x-axis) will "reserve" a
position for every data value that must be manually set. In some ways this is
the same as having a linear scale with major and minor step size set to 1. </p>
<p>As a very basic example of a text scale with a bar graph <a class="xref" href="ch14s08.html#fig.manual_textscale_ex1" title="Figure 14.40. Manual text scale with month labels (manual_textscale_ex1.php)">Figure 14.40. Manual text scale with month labels <code class="uri"><a class="uri" href="example_src/manual_textscale_ex1.html" target="_top">(<code class="filename">manual_textscale_ex1.php</code>)</a></code> </a> shows some fictive values for each
month of the year. In that example the scale has been set to a text scale and
each value has been specified as an array containing all the names of the
months.</p>
<div class="tip" title="Tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3>
<p>An easy way to get hold of the names of the months is to use the library
global instance <code class="code">$gDateLocale</code> of class <code class="code">DateLocale</code>.
This class has several utility methods. For example the two methods</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">GetShortMonthName($aNbr)</code></p>
</li><li class="listitem">
<p><code class="code">GetLongMonthName($aNbr)</code></p>
</li></ul></div><p>
</p>
<p>will return the proper month names (in either short or short or long
format) in the current locale. For more details see <a class="xref" href="ch14s08.html#fig.manual_textscale_ex1" title="Figure 14.40. Manual text scale with month labels (manual_textscale_ex1.php)">Figure 14.40. Manual text scale with month labels <code class="uri"><a class="uri" href="example_src/manual_textscale_ex1.html" target="_top">(<code class="filename">manual_textscale_ex1.php</code>)</a></code> </a>
</p>
</div>
<p>
</p><div class="figure"><a name="id2547469"></a><p class="title"><b>Figure 14.39. Manual text scale example </b></p><div class="figure-contents">
<div class="figure"><a name="fig.manual_textscale_ex1"></a><p class="title"><b>Figure 14.40. Manual text scale with month labels <code class="uri"><a class="uri" href="example_src/manual_textscale_ex1.html" target="_top">(<code class="filename">manual_textscale_ex1.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/manual_textscale_ex1.png" alt="Manual text scale example"></span> </div></div><br class="figure-break">
</div></div><p><br class="figure-break">
</p>
<p>Since the manual text scale sets a scale label for every single data point
this would give problem for the case where we have a large number of data points
where it is not possible to label every data point. In order to control this the
following two methods are used</p>
<p>
</p><div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem">
<p><code class="code">Axis::SetTextTickInterval($aStep,$aStart=0)</code></p>
<p>This method controls the interval between the tick marks for a
text scale. Since by default every tick will have a label it also
specifies how dense the labels will be. The following examples
clarifies how this works</p>
<p>
</p><div class="example"><a name="id2547540"></a><p class="title"><b>Example 14.2. Adjusting manual text tick interval </b></p><div class="example-contents">
<div class="figure"><a name="fig.manual_textscale_ex2"></a><p class="title"><b>Figure 14.41. Setting text tick interval=2 <code class="uri"><a class="uri" href="example_src/manual_textscale_ex2.html" target="_top">(<code class="filename">manual_textscale_ex2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/manual_textscale_ex2.png" alt="Setting text tick interval=2 (manual_textscale_ex2.php)"></span> </div></div><br class="figure-break">
</div></div><p><br class="example-break">
</p>
<p>In the above example only ever second text tick mark is set and
since the labels are also placed at every tick marks only every
second label are shown. </p>
</li><li class="listitem">
<p><code class="code">Axis::SetTextLabelInterval($aStep)</code></p>
<p>This method complements the previous method. This method
exclusively determines where the labels are place. This makes it
possible to have more tick marks than labels. The previous example
<a class="xref" href="ch14s08.html#fig.manual_textscale_ex2" title="Figure 14.41. Setting text tick interval=2 (manual_textscale_ex2.php)">Figure 14.41. Setting text tick interval=2 <code class="uri"><a class="uri" href="example_src/manual_textscale_ex2.html" target="_top">(<code class="filename">manual_textscale_ex2.php</code>)</a></code> </a> look a bit
strange since there are no tick-marks between every second bar. A
better solution in this case would be to have tick marks between
each bar but only label every second tick mark. This is exactly what
can be done with this method. It specifies that every n:th tick mark
should have a label.</p>
<p>In <a class="xref" href="ch14s08.html#fig.manual_textscale_ex3" title="Figure 14.42. Labels at every 2:nd tick mark (manual_textscale_ex3.php)">Figure 14.42. Labels at every 2:nd tick mark <code class="uri"><a class="uri" href="example_src/manual_textscale_ex3.html" target="_top">(<code class="filename">manual_textscale_ex3.php</code>)</a></code> </a> we have used
this method instead.</p>
<p>
</p><div class="example"><a name="id2547630"></a><p class="title"><b>Example 14.3. Adjusting the interval for the labels</b></p><div class="example-contents">
<div class="figure"><a name="fig.manual_textscale_ex3"></a><p class="title"><b>Figure 14.42. Labels at every 2:nd tick mark <code class="uri"><a class="uri" href="example_src/manual_textscale_ex3.html" target="_top">(<code class="filename">manual_textscale_ex3.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/manual_textscale_ex3.png" alt="Labels at every 2:nd tick mark (manual_textscale_ex3.php)"></span> </div></div><br class="figure-break">
</div></div><p><br class="example-break">
</p>
</li></ul></div><p>
</p>
<p>Finally we show an example where there is a need to combine the above two
methods to get a reasonable looking scale. This happens when there are so many
data points that it is not possible to show every tick marks. To show that text
scales can also be used with other plot types than bar we have chosen to show a
line graph where we show data that has 40 data points per month (480 data points
per year). Let us assume that in this application we want to have tick marks at
every 40 points (i.e. a total of 12 tick marks) and have labels only on every
2:th tick label (i.e. a total of 6 labels).</p>
<p>
</p><div class="caution" title="Caution" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Caution</h3>
<p>The label array must have labels for every tick mark even if they are
not shown. </p>
</div><p>
</p>
<p>
</p><div class="example"><a name="id2547704"></a><p class="title"><b>Example 14.4. Adjusting both text tick mark and label interval</b></p><div class="example-contents">
<div class="figure"><a name="fig.manual_textscale_ex4"></a><p class="title"><b>Figure 14.43. Tick marks every 40 points and labels every 2:nd tick mark <code class="uri"><a class="uri" href="example_src/manual_textscale_ex4.html" target="_top">(<code class="filename">manual_textscale_ex4.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/manual_textscale_ex4.png" alt="Tick marks every 40 points and labels every 2:nd tick mark (manual_textscale_ex4.php)"></span> </div></div><br class="figure-break">
</div></div><p><br class="example-break">
</p>
<p>In addition to the text scale is it in principle also possible to use a manual
scale with integer scale as shown in <a class="xref" href="ch04s02.html" title="Graphing the number of sun spots during the 19th Century">Graphing the number of sun spots during the 19th Century</a></p>
<p>
</p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>It is also perfectly legal to override the default labels for the Y
(and Y2) axis in the same way as we have shown for the x-axis but this
is probably a less used scenario. </p>
</div><p>
</p>
<p>
</p><div class="caution" title="Caution" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Caution</h3>
<p>Please note that the supplied labels will be applied to each major
tick label. If there are insufficient number of supplied labels the
non-existent positions will have the ordinal number of the label.</p>
</div><p>
</p>
</div>
<div class="sect2" title="Emphasize of parts of the scale"><div class="titlepage"><div><div><h3 class="title"><a name="id2547382"></a>Emphasize of parts of the scale</h3></div></div></div>
<p>Sometimes it is a good idea to emphasize part of the scale. It can be on
either the x- or the y-axis. The library offers the possibility to add a band
with a separate background color for part of the scale in either x, y (or both)
directions.</p>
<p>A plotband is defined as an instance of <code class="code">class PlotBand</code> that is
added to the graph in the same way as normal plots. A plot band can have a
number of different styles to achieve the wanted affect and it can be placed
either on top or behind the plot.</p>
<p>An instance is created and added to the graph as shown by the following
example</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
3
4
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">// Add a horizontal band
$band = new PlotBand(HORIZONTAL,BAND_RDIAG,15,35,'khaki4');
$band->ShowFrame(false); // No border around the plot band
$graph->Add($band);</span></pre></td></tr></table></div><p>
</p>
<p>The code snippet above adds a horizontal band with a diagonal pattern (from
top left to bottom right). The horizontal band is shown between the y-scale
values [15,35]. </p>
<p>The types of plotbands supported by the library is shown in the table
below</p>
<p>
</p><div class="example"><a name="ex.types-of-plotbands"></a><p class="title"><b>Example 14.5. Different densities for plot bands</b></p><div class="example-contents">
<div class="informaltable">
<table border="0"><colgroup><col class="c1"><col class="c2"><col class="c3"></colgroup><tbody><tr><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex1"></a><p class="title"><b>Figure 14.44. BAND_RDIAG <code class="uri"><a class="uri" href="example_src/smallstaticbandsex1.html" target="_top">(<code class="filename">smallstaticbandsex1.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex1.png" alt="BAND_RDIAG (smallstaticbandsex1.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex2"></a><p class="title"><b>Figure 14.45. BAND_LDIAG <code class="uri"><a class="uri" href="example_src/smallstaticbandsex2.html" target="_top">(<code class="filename">smallstaticbandsex2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex2.png" alt="BAND_LDIAG (smallstaticbandsex2.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex10"></a><p class="title"><b>Figure 14.46. BAND_DIAGCROSS <code class="uri"><a class="uri" href="example_src/smallstaticbandsex10.html" target="_top">(<code class="filename">smallstaticbandsex10.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex10.png" alt="BAND_DIAGCROSS (smallstaticbandsex10.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr><tr><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex7"></a><p class="title"><b>Figure 14.47. BAND_HLINE <code class="uri"><a class="uri" href="example_src/smallstaticbandsex7.html" target="_top">(<code class="filename">smallstaticbandsex7.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex7.png" alt="BAND_HLINE (smallstaticbandsex7.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex6"></a><p class="title"><b>Figure 14.48. BAND_VLINE <code class="uri"><a class="uri" href="example_src/smallstaticbandsex6.html" target="_top">(<code class="filename">smallstaticbandsex6.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex6.png" alt="BAND_VLINE (smallstaticbandsex6.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex5"></a><p class="title"><b>Figure 14.49. BAND_HVCROSS <code class="uri"><a class="uri" href="example_src/smallstaticbandsex5.html" target="_top">(<code class="filename">smallstaticbandsex5.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex5.png" alt="BAND_HVCROSS (smallstaticbandsex5.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr><tr><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex4"></a><p class="title"><b>Figure 14.50. BAND_3DPLANE <code class="uri"><a class="uri" href="example_src/smallstaticbandsex4.html" target="_top">(<code class="filename">smallstaticbandsex4.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex4.png" alt="BAND_3DPLANE (smallstaticbandsex4.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.smallstaticbandsex3"></a><p class="title"><b>Figure 14.51. BAND_SOLID <code class="uri"><a class="uri" href="example_src/smallstaticbandsex3.html" target="_top">(<code class="filename">smallstaticbandsex3.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/smallstaticbandsex3.png" alt="BAND_SOLID (smallstaticbandsex3.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p>
</td></tr></tbody></table>
</div>
</div></div><p><br class="example-break">
</p>
<p>For some of these patterns it is also possible to specify an additional
density parameter via the method <code class="code">PlotBand::SetDensity()</code> that
specifies how dense the pattern should be. For example <a class="xref" href="ch14s08.html#ex.plotband-densities" title="Example 14.6. Different densities for various plot bands">Example 14.6. Different densities for various plot bands</a> shows three variants of the 3D plane
with different density parameters.</p>
<p>
</p><div class="example"><a name="ex.plotband-densities"></a><p class="title"><b>Example 14.6. Different densities for various plot bands</b></p><div class="example-contents">
<div class="informaltable">
<table border="0"><colgroup><col class="c1"><col class="c2"><col class="c3"></colgroup><tbody><tr><td>
<p>
</p><div class="figure"><a name="fig.plotbanddensity_ex0"></a><p class="title"><b>Figure 14.52. SetDensity(10) <code class="uri"><a class="uri" href="example_src/plotbanddensity_ex0.html" target="_top">(<code class="filename">plotbanddensity_ex0.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/plotbanddensity_ex0.png" alt="SetDensity(10) (plotbanddensity_ex0.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.plotbanddensity_ex1"></a><p class="title"><b>Figure 14.53. SetDensity(40) <code class="uri"><a class="uri" href="example_src/plotbanddensity_ex1.html" target="_top">(<code class="filename">plotbanddensity_ex1.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/plotbanddensity_ex1.png" alt="SetDensity(40) (plotbanddensity_ex1.php)"></span> </div></div><p><br class="figure-break">
</p>
</td><td>
<p>
</p><div class="figure"><a name="fig.plotbanddensity_ex2"></a><p class="title"><b>Figure 14.54. SetDensity(80) <code class="uri"><a class="uri" href="example_src/plotbanddensity_ex2.html" target="_top">(<code class="filename">plotbanddensity_ex2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/plotbanddensity_ex2.png" alt="SetDensity(80) (plotbanddensity_ex2.php)"></span> </div></div><p><br class="figure-break">
</p>
</td></tr></tbody></table>
</div>
</div></div><p><br class="example-break">
</p>
<div class="tip" title="Tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3>
<p>3D planes actually carry another possible modification. You can specify
the vanish point to change the perspective used. You can't access the method
to change the horizon directly but you can access it through</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code"> $band ->prect->SetHorizon( $aHorizon)</span></pre></td></tr></table></div><p>
</p>
<p>assuming that the band is a 3D plane.</p>
</div>
<p>To finish this section we show one slightly more creative use of background
plot bands in <a class="xref" href="ch14s08.html#fig.staticbandbarex7" title="Figure 14.56. Creative use of plot bands (staticbandbarex7.php)">Figure 14.56. Creative use of plot bands <code class="uri"><a class="uri" href="example_src/staticbandbarex7.html" target="_top">(<code class="filename">staticbandbarex7.php</code>)</a></code> </a></p>
<p>
</p><div class="figure"><a name="id2548462"></a><p class="title"><b>Figure 14.55. Creative use of plot bands</b></p><div class="figure-contents">
<div class="figure"><a name="fig.staticbandbarex7"></a><p class="title"><b>Figure 14.56. Creative use of plot bands <code class="uri"><a class="uri" href="example_src/staticbandbarex7.html" target="_top">(<code class="filename">staticbandbarex7.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/staticbandbarex7.png" alt="Creative use of plot bands"></span> </div></div><br class="figure-break">
</div></div><p><br class="figure-break">
</p>
</div>
<div class="sect2" title="Adding static lines for specific scale values in the graph"><div class="titlepage"><div><div><h3 class="title"><a name="id2548494"></a>Adding static lines for specific scale values in the graph</h3></div></div></div>
<p>In addition to the plot band it is possible to add static lines to emphasize a
specific scale value. A pot line is added to the graph by creating an instance
of the <code class="code">class PlotLine</code> in much the same way as for plot bands. The
following code snippets show how this can be done</p>
<p>
</p><div class="hl-main"><table class="hl-table" width="100%"><tr><td class="hl-gutter" align="right" valign="top"><pre>1
2
3
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-code">// Add mark graph with static lines
$line = new PlotLine(HORIZONTAL,10,"black",2);
$graph->AddLine($line);</span></pre></td></tr></table></div><p>
</p>
<p>The above code snippets adds a black plot line (weight=2) at scale position
y=10.</p>
<p>In addition to using this feature to show min/max values (or perhaps critical
limits) another usage can be to show a zero-line as the following example in
<a class="xref" href="ch14s08.html#fig.impulsex4" title="Figure 14.58. Adding a static line at y=0 to simulate an extra 0-axis (impulsex4.php)">Figure 14.58. Adding a static line at y=0 to simulate an extra 0-axis <code class="uri"><a class="uri" href="example_src/impulsex4.html" target="_top">(<code class="filename">impulsex4.php</code>)</a></code> </a> shows.</p>
<p>
</p><div class="figure"><a name="id2548541"></a><p class="title"><b>Figure 14.57. Use of a static line to simulate an extra x-axis at y=0</b></p><div class="figure-contents">
<div class="figure"><a name="fig.impulsex4"></a><p class="title"><b>Figure 14.58. Adding a static line at y=0 to simulate an extra 0-axis <code class="uri"><a class="uri" href="example_src/impulsex4.html" target="_top">(<code class="filename">impulsex4.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/impulsex4.png" alt="Use of a static line to simulate an extra x-axis at y=0"></span> </div></div><br class="figure-break">
</div></div><p><br class="figure-break">
</p>
</div>
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