ch01s07.html
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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>What you can do with the library</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="ch01.html" title="Chapter 1. About the library"></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">What you can do with the library</th></tr><tr><td width="20%" align="left"> </td><th width="60%" align="center">Chapter 1. About the library</th><td width="20%" align="right"> </td></tr></table><hr></div><div class="sect1" title="What you can do with the library"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2472677"></a>What you can do with the library</h2></div></div></div>
<p>One should probably differentiate between the two basic usage scenarios</p>
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<p><span class="bold"><strong>Online.</strong></span> That is, the image is dynamically
generated when a user is viewing a particular WEB-page. This means that
the time it takes to generate the image will add to the delay the user
is experiencing when trying to view the page. (The library supports a
caching mechanism to reduce the number of times an image has to
generated, see <a class="xref" href="ch05s06.html" title="Efficient graph generation using the built-in cache subsystem">Efficient graph generation using the built-in cache subsystem</a> for a thorough
discussion). For this scenario one should probably keep the images as
basic as possible in order to have as small latency as possible. </p>
<p>In practice this means that the number of data points to visualize
should be kept in the order of hundreds and not thousands. In later
sections we will discuss in details what can be done to improve the
performance of the library.</p>
<p> </p>
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<p><span class="bold"><strong>Offline</strong></span>. That is, the images are generated by
some "batch" processing (possible command line based). In this scenario
the delay is not an issue and one could create much more complicated
images and process many more data points. Even though the library in
itself does not impose any restriction of the number of data points to
process the memory and time limits set for PHP will. </p>
<p>In practice if you need to process images with sizes above 2000x2000
pixels resulting from processing 500,000 data points then it is probably
better to find a more suitable way to produce these graphs rather than a
PHP script (unless you are prepared to give PHP a couple of 100 MB of
allowed memory)</p>
</li></ol></div><p>
</p>
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