This example shows how to use the pCache class to enhance graph rendering time. Data used to build the graph are static in this example, this will probably be not the case in your application : replace the pData stuff with your own. The unique ID associated to this chart is Graph1, it is needed for the pCache library to get only cached files associated to this script.

After filling the pData structure we're invoking the GetFromCache function. If a cached copy already exists, it is sent to the user browser and the script is interrupted meaning that all the following lines will never be executed.

If the graph isn't in the cache, the chart is created, drawn and then pushed to the cache using the WriteToCache function. Calling this function is mandatory for the cache to be available the next time an user will request the same chart.




Source code :

 <?php
 // Standard inclusions   
 include("pChart/pData.class");
 include("pChart/pChart.class");
 include("pChart/pCache.class");

 // Dataset definition 
 $DataSet = new pData;
 $DataSet->AddPoint(array(1,4,3,2,3,3,2,1,0,7,4,3,2,3,3,5,1,0,7),"Serie1");
 $DataSet->AddPoint(array(1,4,2,6,2,3,0,1,5,1,2,4,5,2,1,0,6,4,2),"Serie2");
 $DataSet->AddAllSeries();
 $DataSet->SetAbsciseLabelSerie();
 $DataSet->SetSerieName("January","Serie1");
 $DataSet->SetSerieName("February","Serie2");

 // Cache definition 
 $Cache = new pCache();
 $Cache->GetFromCache("Graph1",$DataSet->GetData());

 // Initialise the graph
 $Test = new pChart(700,230);
 $Test->setFontProperties("Fonts/tahoma.ttf",8);
 $Test->setGraphArea(50,30,585,200);
 $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);   
 $Test->drawGrid(4,TRUE,230,230,230,50);

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

 // Draw the cubic curve graph
 $Test->drawCubicCurve($DataSet->GetData(),$DataSet->GetDataDescription());

 // Finish the graph
 $Test->setFontProperties("Fonts/tahoma.ttf",8);
 $Test->drawLegend(600,30,$DataSet->GetDataDescription(),255,255,255);
 $Test->setFontProperties("Fonts/tahoma.ttf",10);
 $Test->drawTitle(50,22,"Example 1",50,50,50,585);

 // Render the graph
 $Cache->WriteToCache("Graph1",$DataSet->GetData(),$Test);
 $Test->Stroke();
 ?>
 

Using the cache work only for graphs that are sent to the user browser using the Stroke() command.