Since release 1.27d it is possible to draw shadows behind drawn pixels. Shadow can be added to any plot-drawn objects line lines and cubics. Use shadows with caution as this will add extra computing time to your charts. If you want to display rendered data on your web pages, I invite you to use the pCache class to speed up the processing time.

This example is showing how to display two data series with dedicated Y axis. Basic way to associate a data serie to one axis is to first add only the attached data series to the grapher using the AddSerie() function of the pData class and then invoke the drawScale() function of the pChart class. Before drawing the right scale, use the clearScale() function and remove the previously graphed series with the RemoveSerie() function of the pData class. Then add the remaining series using the AddSerie() function and compute the second Y axis calling the drawRightScale() function.

Shadows are activated calling the setShadowProperties() function. You must remove the shadow engine calling the clearShadow() when you've finished to draw your data series. If you forget to remove the shadow, you'll experience strange graphing effects.

Running this script will create a example26.png file in the current directory.

Output :


Source code :

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

  // Dataset definition 
  $DataSet = new pData;
  $DataSet->AddPoint(array(110,101,118,108,110,106,104),"Serie1");
  $DataSet->AddPoint(array(700,2705,2041,1712,2051,846,903),"Serie2");
  $DataSet->AddPoint(array("03 Oct","02 Oct","01 Oct","30 Sep","29 Sep","28 Sep","27 Sep"),"Serie3");
  $DataSet->AddSerie("Serie1");
  $DataSet->SetAbsciseLabelSerie("Serie3");
  $DataSet->SetSerieName("SourceForge Rank","Serie1");
  $DataSet->SetSerieName("Web Hits","Serie2");

  // Initialise the graph
  $Test = new pChart(660,230);
  $Test->drawGraphAreaGradient(90,90,90,90,TARGET_BACKGROUND);

  // Prepare the graph area
  $Test->setFontProperties("fonts/tahoma.ttf",8);
  $Test->setGraphArea(60,40,595,190);

  // Initialise graph area
  $Test->setFontProperties("fonts/tahoma.ttf",8);

  // Draw the SourceForge Rank graph
  $DataSet->SetYAxisName("Sourceforge Rank");
  $Test->drawScale($DataSet->GetData(),$DataSet->GetDataDescription(),SCALE_NORMAL,213,217,221,TRUE,0,0);
  $Test->drawGraphAreaGradient(40,40,40,-50);
  $Test->drawGrid(4,TRUE,230,230,230,10);
  $Test->setShadowProperties(3,3,0,0,0,30,4);
  $Test->drawCubicCurve($DataSet->GetData(),$DataSet->GetDataDescription());
  $Test->clearShadow();
  $Test->drawFilledCubicCurve($DataSet->GetData(),$DataSet->GetDataDescription(),.1,30);
  $Test->drawPlotGraph($DataSet->GetData(),$DataSet->GetDataDescription(),3,2,255,255,255);

  // Clear the scale
  $Test->clearScale();

  // Draw the 2nd graph
  $DataSet->RemoveSerie("Serie1");
  $DataSet->AddSerie("Serie2");
  $DataSet->SetYAxisName("Web Hits");
  $Test->drawRightScale($DataSet->GetData(),$DataSet->GetDataDescription(),SCALE_NORMAL,213,217,221,TRUE,0,0);
  $Test->drawGrid(4,TRUE,230,230,230,10);
  $Test->setShadowProperties(3,3,0,0,0,30,4);
  $Test->drawCubicCurve($DataSet->GetData(),$DataSet->GetDataDescription());
  $Test->clearShadow();
  $Test->drawFilledCubicCurve($DataSet->GetData(),$DataSet->GetDataDescription(),.1,30);
  $Test->drawPlotGraph($DataSet->GetData(),$DataSet->GetDataDescription(),3,2,255,255,255);

  // Write the legend (box less)
  $Test->setFontProperties("fonts/tahoma.ttf",8);
  $Test->drawLegend(530,5,$DataSet->GetDataDescription(),0,0,0,0,0,0,255,255,255,FALSE);

  // Write the title
  $Test->setFontProperties("fonts/MankSans.ttf",18);
  $Test->setShadowProperties(1,1,0,0,0);
  $Test->drawTitle(0,0,"SourceForge ranking summary",255,255,255,660,30,TRUE);
  $Test->clearShadow();

  // Render the picture
  $Test->Render("example26.png");
 ?>
 

If you want to send the picture directly in a browser, replace the Render() command by Stroke().