PHP生成图表pChart入门教程

pChart是一个开源的图表生成库，主要涉及3个Class：pChart.class, pData.class, pCache.class，可生成20多种简单或复杂的图表，支持PNG，JPG，GIF通用图片格式。数据源可以来自于Database，CSV，当然也可以手写。使用该程序PHP需要开启GD服务，先来看看pChart的工作流程：

主要分为三步：

1. * 读取用于生成图表数据（数据库、文件）
2. * 设计图表样式（圆角、底色等）
3. * 制作标签、题目、图例并生成图表

 

下面看一个简单的柱状图表：

代码如下：

<span style="color: blue"><?php </span><span style="color: green">// Standard inclusions   
 </span><span style="color: blue">include</span><span style="color: purple">(</span><span style="color: olive">"pChart/pData.class"</span><span style="color: purple">)</span>;
 <span style="color: blue">include</span><span style="color: purple">(</span><span style="color: olive">"pChart/pChart.class"</span><span style="color: purple">)</span>;

 <span style="color: green">// Dataset definition 
 </span><span style="color: blue">$DataSet </span><span style="color: purple">= </span><span style="color: blue">new </span>pData;
 <span style="color: green">//图表数据
 </span><span style="color: blue">$DataSet</span><span style="color: purple">-></span>AddPoint<span style="color: purple">(</span><span style="color: blue">array</span><span style="color: purple">(</span><span style="color: red">1</span><span style="color: purple">,</span><span style="color: red">4</span><span style="color: purple">,-</span><span style="color: red">3</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">,-</span><span style="color: red">3</span><span style="color: purple">,</span><span style="color: red">3</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">,</span><span style="color: red">1</span><span style="color: purple">,</span><span style="color: red">0</span><span style="color: purple">,</span><span style="color: red">7</span><span style="color: purple">,</span><span style="color: red">4</span><span style="color: purple">),</span><span style="color: olive">"Serie1"</span><span style="color: purple">)</span>;
 <span style="color: blue">$DataSet</span><span style="color: purple">-></span>AddPoint<span style="color: purple">(</span><span style="color: blue">array</span><span style="color: purple">(</span><span style="color: red">3</span><span style="color: purple">,</span><span style="color: red">3</span><span style="color: purple">,-</span><span style="color: red">4</span><span style="color: purple">,</span><span style="color: red">1</span><span style="color: purple">,-</span><span style="color: red">2</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">,</span><span style="color: red">1</span><span style="color: purple">,</span><span style="color: red">0</span><span style="color: purple">,-</span><span style="color: red">1</span><span style="color: purple">,</span><span style="color: red">6</span><span style="color: purple">,</span><span style="color: red">3</span><span style="color: purple">),</span><span style="color: olive">"Serie2"</span><span style="color: purple">)</span>;
 <span style="color: blue">$DataSet</span><span style="color: purple">-></span>AddPoint<span style="color: purple">(</span><span style="color: blue">array</span><span style="color: purple">(</span><span style="color: red">4</span><span style="color: purple">,</span><span style="color: red">1</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">,-</span><span style="color: red">1</span><span style="color: purple">,-</span><span style="color: red">4</span><span style="color: purple">,-</span><span style="color: red">2</span><span style="color: purple">,</span><span style="color: red">3</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">,</span><span style="color: red">1</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">,</span><span style="color: red">2</span><span style="color: purple">),</span><span style="color: olive">"Serie3"</span><span style="color: purple">)</span>;
 <span style="color: blue">$DataSet</span><span style="color: purple">-></span>AddAllSeries<span style="color: purple">()</span>;
 <span style="color: blue">$DataSet</span><span style="color: purple">-></span>SetAbsciseLabelSerie<span style="color: purple">()</span>;
 <span style="color: green">//数据图例
 </span><span style="color: blue">$DataSet</span><span style="color: purple">-></span>SetSerieName<span style="color: purple">(</span><span style="color: olive">"Microsoft"</span><span style="color: purple">,</span><span style="color: olive">"Serie1"</span><span style="color: purple">)</span>;
 <span style="color: blue">$DataSet</span><span style="color: purple">-></span>SetSerieName<span style="color: purple">(</span><span style="color: olive">"IBM"</span><span style="color: purple">,</span><span style="color: olive">"Serie2"</span><span style="color: purple">)</span>;
 <span style="color: blue">$DataSet</span><span style="color: purple">-></span>SetSerieName<span style="color: purple">(</span><span style="color: olive">"Google"</span><span style="color: purple">,</span><span style="color: olive">"Serie3"</span><span style="color: purple">)</span>;

 <span style="color: green">// Initialise the graph
 </span><span style="color: blue">$Test </span><span style="color: purple">= </span><span style="color: blue">new </span>pChart<span style="color: purple">(</span><span style="color: red">700</span><span style="color: purple">,</span><span style="color: red">230</span><span style="color: purple">)</span>;
 <span style="color: green">//设置图表尺寸、样式
 </span><span style="color: blue">$Test</span><span style="color: purple">-></span>setFontProperties<span style="color: purple">(</span><span style="color: olive">"Fonts/tahoma.ttf"</span><span style="color: purple">,</span><span style="color: red">8</span><span style="color: purple">)</span>;
 <span style="color: blue">$Test</span><span style="color: purple">-></span>setGraphArea<span style="color: purple">(</span><span style="color: red">50</span><span style="color: purple">,</span><span style="color: red">30</span><span style="color: purple">,</span><span style="color: red">680</span><span style="color: purple">,</span><span style="color: red">200</span><span style="color: purple">)</span>;
 <span style="color: blue">$Test</span><span style="color: purple">-></span>drawFilledRoundedRectangle<span style="color: purple">(</span><span style="color: red">7</span><span style="color: purple">,</span><span style="color: red">7</span><span style="color: purple">,</span><span style="color: red">693
</span></span>