This function will draw a vertical threshold in the chart area. Using thresholds can help you to highlight specific values. It is possible to tune the rendering by playing with the $Format array. To learn more about this please read the Format array guide.

drawXThreshold($Value,$Format="");

Where :


This function returns an array containing the Y position of the threshold line.


It is possible to customize the way your threshold will be rendered by playing with this array. Providing a detailled configuration is not mandatory, by default the line will be drawn dashed in red.



If you choose to draw a box under the caption, all the drawText() extended styles can be used (DrawBoxBorder,BorderOffset,BoxRounded, ...) to have the complete list of parameters, take a look at the drawText() page.

The captions can be aligned using CaptionAlign the following ways :

 /* pChart library inclusions */ 
 include("../class/pData.class.php"); 
 include("../class/pDraw.class.php"); 
 include("../class/pImage.class.php"); 

 /* Create and populate the pData object */ 
 $MyData = new pData();   
 $MyData->addPoints(array(24,-25,26,25,25),"Temperature"); 
 $MyData->setAxisName(0,"Temperatures"); 
 $MyData->addPoints(array("Jan","Feb","Mar","Apr","May","Jun"),"Labels"); 
 $MyData->setSerieDescription("Labels","Months"); 
 $MyData->setAbscissa("Labels"); 

 /* Create the pChart object */ 
 $myPicture = new pImage(700,230,$MyData); 

 /* Draw the background */ 
 $Settings = array("R"=>170, "G"=>183, "B"=>87, "Dash"=>1, "DashR"=>190, "DashG"=>203, "DashB"=>107);
 $myPicture->drawFilledRectangle(0,0,700,230,$Settings); 

 /* Overlay with a gradient */ 
 $Settings = array("StartR"=>219, "StartG"=>231, "StartB"=>139, "EndR"=>1, "EndG"=>138, "EndB"=>68, "Alpha"=>50);
  $myPicture->drawGradientArea(0,0,700,230,DIRECTION_VERTICAL,$Settings); 
 $myPicture->drawGradientArea(0,0,700,20,DIRECTION_VERTICAL,array("StartR"=>0,"StartG"=>0,"StartB"=>0,"EndR"=>50,"EndG"=>50,"EndB"=>50,"Alpha"=>80));
 
 /* Add a border to the picture */ 
 $myPicture->drawRectangle(0,0,699,229,array("R"=>0,"G"=>0,"B"=>0)); 
  
 /* Write the picture title */  
 $myPicture->setFontProperties(array("FontName"=>"../fonts/Silkscreen.ttf","FontSize"=>6));
 $myPicture->drawText(10,13,"drawThreshold() - draw a treshold in the charting area",array("R"=>255,"G"=>255,"B"=>255));
 
 /* Write the chart title */  
 $myPicture->setFontProperties(array("FontName"=>"../fonts/Forgotte.ttf","FontSize"=>11));
  $myPicture->drawText(250,55,"My chart title",array("FontSize"=>20,"Align"=>TEXT_ALIGN_BOTTOMMIDDLE));
 
 /* Draw the scale and do some cosmetics */  
 $myPicture->setGraphArea(60,60,450,190); 
 $myPicture->drawFilledRectangle(70,70,440,180,array("R"=>255,"G"=>255,"B"=>255,"Surrounding"=>-200,"Alpha"=>10));
 $myPicture->drawScale(array("XMargin"=>10,"YMargin"=>10,"Floating"=>TRUE,"DrawSubTicks"=>TRUE));
 $myPicture->setShadow(TRUE,array("X"=>1,"Y"=>1,"R"=>0,"G"=>0,"B"=>0,"Alpha"=>20)); 
 
 /* Draw static thresholds */  
 $myPicture->setFontProperties(array("FontName"=>"../fonts/Forgotte.ttf","FontSize"=>10));
 $myPicture->drawXThreshold("Feb",array("ValueIsLabel"=>TRUE,"WriteCaption"=>TRUE,"Caption"=>"Step 1","Alpha"=>70,"Ticks"=>1));
 $myPicture->drawXThreshold(2,array("WriteCaption"=>TRUE,"Caption"=>"Step 2","Alpha"=>70,"Ticks"=>2,"R"=>0,"G"=>0,"B"=>255));
 
 /* Disable shadow computing */  
 $myPicture->setShadow(FALSE); 

 /* Draw the scale and do some cosmetics */  
 $myPicture->setGraphArea(500,60,670,190); 
 $myPicture->drawFilledRectangle(505,65,665,185,array("R"=>255,"G"=>255,"B"=>255,"Surrounding"=>-200,"Alpha"=>10));
 $myPicture->setFontProperties(array("FontName"=>"../fonts/Forgotte.ttf","FontSize"=>11));
 $myPicture->drawScale(array("XMargin"=>5,"YMargin"=>5,"Floating"=>TRUE,"Pos"=>SCALE_POS_TOPBOTTOM,"DrawSubTicks"=>TRUE));
 $myPicture->setShadow(TRUE,array("X"=>1,"Y"=>1,"R"=>0,"G"=>0,"B"=>0,"Alpha"=>20)); 
 
 /* Draw static thresholds */  
 $myPicture->drawXThreshold(array(1,3),array("Alpha"=>70,"Ticks"=>1)); 
 $myPicture->drawXThreshold(2,array("Alpha"=>70,"Ticks"=>2,"R"=>0,"G"=>0,"B"=>255));
 
 /* Render the picture (choose the best way) */ 
 $myPicture->autoOutput("pictures/example.drawXThreshold.png");