解析PHP生成图表pChart的示例

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：

相关学习推荐：PHP编程从入门到精通

主要分为三步：

* 读取用于生成图表数据（数据库、文件）
* 设计图表样式（圆角、底色等）
* 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：

AddPoint(array(1,4,-3,2,-3,3,2,1,0,7,4),"Serie1");
 $DataSet->AddPoint(array(3,3,-4,1,-2,2,1,0,-1,6,3),"Serie2");
 $DataSet->AddPoint(array(4,1,2,-1,-4,-2,3,2,1,2,2),"Serie3");
 $DataSet->AddAllSeries();
 $DataSet->SetAbsciseLabelSerie();
 //数据图例
 $DataSet->SetSerieName("Microsoft","Serie1");
 $DataSet->SetSerieName("IBM","Serie2");
 $DataSet->SetSerieName("Google","Serie3");

 // Initialise the graph
 $Test = new pChart(700,230);
 //设置图表尺寸、样式
 $Test->setFontProperties("Fonts/tahoma.ttf",8);
 $Test->setGraphArea(50,30,680,200);
 $Test->drawFilledRoundedRectangle(7,7,693,223,5,240,240,240);
 $Test->drawRoundedRectangle(5,5,695,225,5,230,230,230);
 $Test->drawGraphArea(255,255,255,TRUE);
 $Test->drawScale($DataSet->GetData(),$DataSet->GetDataDescription(),SCALE_NORMAL,150,150,150,TRUE,0,2,TRUE);
 $Test->drawGrid(4,TRUE,230,230,230,50);

 // Draw the 0 line
 $Test->setFontProperties("Fonts/MankSans.ttf",6);
 $Test->drawTreshold(0,143,55,72,TRUE,TRUE);

 // Draw the bar graph
 //柱状图要使用drawBarGraph()
 $Test->drawBarGraph($DataSet->GetData(),$DataSet->GetDataDescription(),TRUE,80);


 // Finish the graph
 //制作图例、标题、字体等属性
 $Test->setFontProperties("Fonts/MankSans.ttf",10);
 $Test->drawLegend(596,150,$DataSet->GetDataDescription(),255,255,255);
 $Test->setFontProperties("Fonts/MankSans.ttf",10);
 $Test->drawTitle(50,22,"Example",50,50,50,585);
 
 //生成图表
 $imageFile = "example12.png";
 $Test->Render($imageFile);
 echo '';
?>

这个是雷达效果的：

代码：

AddPoint(array("Memory","Disk","Network","Slots","CPU"),"Label");
 $DataSet->AddPoint(array(6,4,7,4,5),"Serie1");
 $DataSet->AddPoint(array(2,3,5,2,4),"Serie2");
 $DataSet->AddSerie("Serie1");
 $DataSet->AddSerie("Serie2");
 $DataSet->SetAbsciseLabelSerie("Label");


 $DataSet->SetSerieName("Reference","Serie1");
 $DataSet->SetSerieName("Tested computer","Serie2");

 // Initialise the graph
 $Test = new pChart(400,400);
 $Test->setFontProperties("Fonts/tahoma.ttf",8);
 $Test->drawFilledRoundedRectangle(7,7,393,393,5,240,240,240);
 $Test->drawRoundedRectangle(5,5,395,395,5,230,230,230);
 $Test->setGraphArea(30,30,370,370);
 $Test->drawFilledRoundedRectangle(30,30,370,370,5,255,255,255);
 $Test->drawRoundedRectangle(30,30,370,370,5,220,220,220);

 // Draw the radar graph
 //要使用drawRadarAxis()生成雷达效果
 $Test->drawRadarAxis($DataSet->GetData(),$DataSet->GetDataDescription(),TRUE,20,120,120,120,230,230,230);
 $Test->drawFilledRadar($DataSet->GetData(),$DataSet->GetDataDescription(),50,20);

 // Finish the graph
 $Test->drawLegend(15,15,$DataSet->GetDataDescription(),255,255,255);
 $Test->setFontProperties("Fonts/tahoma.ttf",10);
 $Test->drawTitle(0,22,"Example",50,50,50,400);
 
 $imageFile = "example8.png";
 $Test->Render($imageFile);
 echo '';
?>

再看几个其他的效果

1，饼图：