166 lines
21 KiB
HTML
166 lines
21 KiB
HTML
|
<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Chapter 32. Synchronized Y-axis</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="pt08.html" title="Part VIII. Case studies"></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">Chapter 32. Synchronized Y-axis</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center">Part VIII. Case studies</th><td width="20%" align="right"> </td></tr></table><hr></div><div class="chapter" title="Chapter 32. Synchronized Y-axis"><div class="titlepage"><div><div><h2 class="title"><a name="id2619882"></a>Chapter 32. Synchronized Y-axis</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="sect1"><a href="ch32.html#id2619942">32.1. Creating two scales</a></span></dt></dl></div>
|
|||
|
|
|
|||
|
|
<p>The purpose of this chapter is to show how one can have one set of data displayed with
|
|||
|
|
two different scales that are still synchronized meaning that the tick marks are at
|
|||
|
|
identical positions.</p>
|
|||
|
|
<p> One classic example of when this can be useful is to show temperature in both Celsius
|
|||
|
|
and Fahrenheit. <a class="xref" href="ch32.html#fig.y2synch" title="Figure 32.1. Synchronized y and y2 scales (y2synch.php)">Figure 32.1. Synchronized y and y2 scales <code class="uri"><a class="uri" href="example_src/y2synch.html" target="_top">(<code class="filename">y2synch.php</code>)</a></code> </a> below illustrates what we would like
|
|||
|
|
to accomplish. </p>
|
|||
|
|
<p>
|
|||
|
|
</p><div class="figure"><a name="fig.y2synch"></a><p class="title"><b>Figure 32.1. Synchronized y and y2 scales <code class="uri"><a class="uri" href="example_src/y2synch.html" target="_top">(<code class="filename">y2synch.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/y2synch.png" alt="Synchronized y and y2 scales (y2synch.php)"></span> </div></div><p><br class="figure-break">
|
|||
|
|
</p>
|
|||
|
|
<div class="sect1" title="Creating two scales"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2619942"></a>Creating two scales</h2></div></div></div>
|
|||
|
|
|
|||
|
|
<p>Normally the auto scaling puts tick marks at "nice" positions that for example are
|
|||
|
|
multiples of 5,2,10 and so on. This would mean that it seems like the graph in <a class="xref" href="ch32.html#fig.y2synch" title="Figure 32.1. Synchronized y and y2 scales (y2synch.php)">Figure 32.1. Synchronized y and y2 scales <code class="uri"><a class="uri" href="example_src/y2synch.html" target="_top">(<code class="filename">y2synch.php</code>)</a></code> </a> with tick positions at 59 F and 68 F can not be auto
|
|||
|
|
scaled. </p>
|
|||
|
|
<p>The simplest method of creating two scales as in the example above is to add a
|
|||
|
|
secondary Y-axis, add the same plot to that axis. This would then mean that the two
|
|||
|
|
axes would be identical. The magic now happens in the last step when we add a format
|
|||
|
|
callback method to the second Y-axis. This format callback will be applied to each
|
|||
|
|
label. All we have to do now is create a callback function that does the proper
|
|||
|
|
scale conversion.</p>
|
|||
|
|
<p>This way also means that we have too chose one of the scales as the "master" which
|
|||
|
|
will be auto scaled with tick positions at "nice" intervals. </p>
|
|||
|
|
<p>
|
|||
|
|
</p><div class="caution" title="Caution" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Caution</h3>
|
|||
|
|
<p>For the second scale one can add the same plot or one could create a new
|
|||
|
|
plot from the same data set. If the data set to be plotted is very large it
|
|||
|
|
can be advantageous to create a new plot and set the line weight to 0
|
|||
|
|
(zero). This way the line will not actually be plotted and that plot time is
|
|||
|
|
eliminated. </p>
|
|||
|
|
</div><p>
|
|||
|
|
</p>
|
|||
|
|
<p>The script to create the graph in <a class="xref" href="ch32.html#fig.y2synch" title="Figure 32.1. Synchronized y and y2 scales (y2synch.php)">Figure 32.1. Synchronized y and y2 scales <code class="uri"><a class="uri" href="example_src/y2synch.html" target="_top">(<code class="filename">y2synch.php</code>)</a></code> </a> is given
|
|||
|
|
below. </p>
|
|||
|
|
<p>
|
|||
|
|
</p><div class="example"><a name="example.y2synch"></a><p class="title"><b>Example 32.1. (<code class="filename">y2synch.php</code>) </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
|
|||
|
|
3
|
|||
|
|
4
|
|||
|
|
5
|
|||
|
|
6
|
|||
|
|
7
|
|||
|
|
8
|
|||
|
|
9
|
|||
|
|
10
|
|||
|
|
11
|
|||
|
|
12
|
|||
|
|
13
|
|||
|
|
14
|
|||
|
|
15
|
|||
|
|
16
|
|||
|
|
17
|
|||
|
|
18
|
|||
|
|
19
|
|||
|
|
20
|
|||
|
|
21
|
|||
|
|
22
|
|||
|
|
23
|
|||
|
|
24
|
|||
|
|
25
|
|||
|
|
26
|
|||
|
|
27
|
|||
|
|
28
|
|||
|
|
29
|
|||
|
|
30
|
|||
|
|
31
|
|||
|
|
32
|
|||
|
|
33
|
|||
|
|
34
|
|||
|
|
35
|
|||
|
|
36
|
|||
|
|
37
|
|||
|
|
38
|
|||
|
|
39
|
|||
|
|
40
|
|||
|
|
41
|
|||
|
|
42
|
|||
|
|
43
|
|||
|
|
44
|
|||
|
|
45
|
|||
|
|
46
|
|||
|
|
47
|
|||
|
|
48
|
|||
|
|
49
|
|||
|
|
50
|
|||
|
|
51
|
|||
|
|
52
|
|||
|
|
53
|
|||
|
|
54
|
|||
|
|
55
|
|||
|
|
56
|
|||
|
|
57
|
|||
|
|
58
|
|||
|
|
59
|
|||
|
|
60
|
|||
|
|
</pre></td><td class="hl-main" valign="top"><pre><span class="hl-inlinetags"><?php</span><span class="hl-code"> </span><span class="hl-comment">//</span><span class="hl-comment"> content="text/plain; charset=utf-8"</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph_line.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-reserved">require_once</span><span class="hl-code"> </span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">jpgraph/jpgraph_bar.php</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
|
|||
|
|
</span><span class="hl-reserved">function</span><span class="hl-code"> </span><span class="hl-identifier">toFahrenheit</span><span class="hl-brackets">(</span><span class="hl-var">$aVal</span><span class="hl-brackets">)</span><span class="hl-code"> </span><span class="hl-brackets">{</span><span class="hl-code">
|
|||
|
|
</span><span class="hl-reserved">return</span><span class="hl-code"> </span><span class="hl-identifier">round</span><span class="hl-brackets">(</span><span class="hl-brackets">(</span><span class="hl-var">$aVal</span><span class="hl-code">*</span><span class="hl-number">9</span><span class="hl-code">/</span><span class="hl-number">5</span><span class="hl-brackets">)</span><span class="hl-code">+</span><span class="hl-number">32</span><span class="hl-code">,</span><span class="hl-number">2</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-brackets">}</span><span class="hl-code">
|
|||
|
|
|
|||
|
|
</span><span class="hl-reserved">function</span><span class="hl-code"> </span><span class="hl-identifier">toCelcius</span><span class="hl-brackets">(</span><span class="hl-var">$aVal</span><span class="hl-brackets">)</span><span class="hl-code"> </span><span class="hl-brackets">{</span><span class="hl-code">
|
|||
|
|
</span><span class="hl-reserved">return</span><span class="hl-code"> </span><span class="hl-identifier">round</span><span class="hl-brackets">(</span><span class="hl-brackets">(</span><span class="hl-var">$aVal</span><span class="hl-code">-</span><span class="hl-number">32</span><span class="hl-brackets">)</span><span class="hl-code">*</span><span class="hl-number">5</span><span class="hl-code">/</span><span class="hl-number">9</span><span class="hl-code">,</span><span class="hl-number">2</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-brackets">}</span><span class="hl-code">
|
|||
|
|
|
|||
|
|
|
|||
|
|
</span><span class="hl-var">$datay</span><span class="hl-code"> =</span><span class="hl-reserved">array</span><span class="hl-brackets">(</span><span class="hl-number">2</span><span class="hl-code">,</span><span class="hl-number">3</span><span class="hl-code">,</span><span class="hl-number">8</span><span class="hl-code">,</span><span class="hl-number">19</span><span class="hl-code">,</span><span class="hl-number">7</span><span class="hl-code">,</span><span class="hl-number">17</span><span class="hl-code">,</span><span class="hl-number">6</span><span class="hl-code">,</span><span class="hl-number">22</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Create the graph. </span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">Graph</span><span class="hl-brackets">(</span><span class="hl-number">400</span><span class="hl-code">,</span><span class="hl-number">280</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Slightly bigger margins than default to make room for titles</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">SetMargin</span><span class="hl-brackets">(</span><span class="hl-number">50</span><span class="hl-code">,</span><span class="hl-number">60</span><span class="hl-code">,</span><span class="hl-number">40</span><span class="hl-code">,</span><span class="hl-number">45</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">SetMarginColor</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">white</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Setup the scales for X,Y and Y2 axis</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">SetScale</span><span class="hl-brackets">(</span><span class="hl-quotes">"</span><span class="hl-string">intlin</span><span class="hl-quotes">"</span><span class="hl-brackets">)</span><span class="hl-code">; </span><span class="hl-comment">//</span><span class="hl-comment"> X and Y axis</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">SetY2Scale</span><span class="hl-brackets">(</span><span class="hl-quotes">"</span><span class="hl-string">lin</span><span class="hl-quotes">"</span><span class="hl-brackets">)</span><span class="hl-code">; </span><span class="hl-comment">//</span><span class="hl-comment"> Y2 axis</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Overall graph title</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">Synchronized Y & Y2 scales</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetFont</span><span class="hl-brackets">(</span><span class="hl-identifier">FF_ARIAL</span><span class="hl-code">,</span><span class="hl-identifier">FS_BOLD</span><span class="hl-code">,</span><span class="hl-number">12</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Title for X-axis</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">xaxis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">Measurement</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">xaxis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetMargin</span><span class="hl-brackets">(</span><span class="hl-number">5</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">xaxis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetFont</span><span class="hl-brackets">(</span><span class="hl-identifier">FF_ARIAL</span><span class="hl-code">,</span><span class="hl-identifier">FS_NORMAL</span><span class="hl-code">,</span><span class="hl-number">11</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Create Y data set </span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$lplot</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">LinePlot</span><span class="hl-brackets">(</span><span class="hl-var">$datay</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">yaxis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">Celcius (C)</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">yaxis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetMargin</span><span class="hl-brackets">(</span><span class="hl-number">5</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">yaxis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetFont</span><span class="hl-brackets">(</span><span class="hl-identifier">FF_ARIAL</span><span class="hl-code">,</span><span class="hl-identifier">FS_NORMAL</span><span class="hl-code">,</span><span class="hl-number">11</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> ... and add the plot to the Y-axis</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Add</span><span class="hl-brackets">(</span><span class="hl-var">$lplot</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> Create Y2 scale data set </span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$l2plot</span><span class="hl-code"> = </span><span class="hl-reserved">new</span><span class="hl-code"> </span><span class="hl-identifier">LinePlot</span><span class="hl-brackets">(</span><span class="hl-var">$datay</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$l2plot</span><span class="hl-code">-></span><span class="hl-identifier">SetWeight</span><span class="hl-brackets">(</span><span class="hl-number">0</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">y2axis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">Set</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">Fahrenheit (F)</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">y2axis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetMargin</span><span class="hl-brackets">(</span><span class="hl-number">5</span><span class="hl-brackets">)</span><span class="hl-code">; </span><span class="hl-comment">//</span><span class="hl-comment"> Some extra margin to clear labels</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">y2axis</span><span class="hl-code">-></span><span class="hl-identifier">title</span><span class="hl-code">-></span><span class="hl-identifier">SetFont</span><span class="hl-brackets">(</span><span class="hl-identifier">FF_ARIAL</span><span class="hl-code">,</span><span class="hl-identifier">FS_NORMAL</span><span class="hl-code">,</span><span class="hl-number">11</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">y2axis</span><span class="hl-code">-></span><span class="hl-identifier">SetLabelFormatCallback</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">toFahrenheit</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">y2axis</span><span class="hl-code">-></span><span class="hl-identifier">SetColor</span><span class="hl-brackets">(</span><span class="hl-quotes">'</span><span class="hl-string">navy</span><span class="hl-quotes">'</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-comment">//</span><span class="hl-comment"> ... and add the plot to the Y2-axis</span><span class="hl-comment"></span><span class="hl-code">
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">AddY2</span><span class="hl-brackets">(</span><span class="hl-var">$l2plot</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
|
|||
|
|
</span><span class="hl-var">$graph</span><span class="hl-code">-></span><span class="hl-identifier">Stroke</span><span class="hl-brackets">(</span><span class="hl-brackets">)</span><span class="hl-code">;
|
|||
|
|
</span><span class="hl-inlinetags">?></span></pre></td></tr></table></div></div></div><p><br class="example-break">
|
|||
|
|
</p>
|
|||
|
|
<p>The same principle will also work with othrr plot variants, for example bar plots.
|
|||
|
|
By making the first plot an instance of <code class="code">class BarPlot</code> the graph in
|
|||
|
|
<a class="xref" href="ch32.html#fig.y2synch2" title="Figure 32.2. Using a barplot with two different scales (y2synch2.php)">Figure 32.2. Using a barplot with two different scales <code class="uri"><a class="uri" href="example_src/y2synch2.html" target="_top">(<code class="filename">y2synch2.php</code>)</a></code> </a> can be created. </p>
|
|||
|
|
<p>
|
|||
|
|
</p><div class="figure"><a name="fig.y2synch2"></a><p class="title"><b>Figure 32.2. Using a barplot with two different scales <code class="uri"><a class="uri" href="example_src/y2synch2.html" target="_top">(<code class="filename">y2synch2.php</code>)</a></code> </b></p><div class="figure-contents"> <span class="inlinemediaobject"><img src="images/y2synch2.png" alt="Using a barplot with two different scales (y2synch2.php)"></span> </div></div><p><br class="figure-break">
|
|||
|
|
</p>
|
|||
|
|
</div>
|
|||
|
|
</div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"> </td><td width="20%" align="center"><a accesskey="u" href="pt08.html">Up</a></td><td width="40%" align="right"> </td></tr><tr><td width="40%" align="left" valign="top"> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> </td></tr></table></div></body></html>
|