PHP warning

imageftbbox(): Could not find/open font

/var/www/html/application/third_party/pchart/pChart.class.php(2653)

2641        /* Process labels position & size */
2642        $Caption = "";
2643        if ( !($DrawLabels == PIE_NOLABEL) )
2644         {
2645          $TAngle   = $Angle+($Value*$SpliceRatio/2);
2646          if ($DrawLabels == PIE_PERCENTAGE)
2647           $Caption  = (round($rValues[$Key] * pow(10,$Decimals) * $rSplicePercent)/pow(10,$Decimals))."%";
2648          elseif ($DrawLabels == PIE_LABELS)
2649           $Caption  = $iLabels[$Key];
2650          elseif ($DrawLabels == PIE_PERCENTAGE_LABEL)
2651           $Caption  = $iLabels[$Key]."\r\n".(round($Value * pow(10,$Decimals) * $SplicePercent)/pow(10,$Decimals))."%";
2652
2653          $Position   = imageftbbox($this->FontSize,0,$this->FontName,$Caption);
2654          $TextWidth  = $Position[2]-$Position[0];
2655          $TextHeight = abs($Position[1])+abs($Position[3]);
2656
2657          $TX = cos(($TAngle) * 3.1418 / 180 ) * ($Radius + 10)+ $XPos;
2658
2659          if ( $TAngle > 0 && $TAngle < 180 )
2660           $TY = sin(($TAngle) * 3.1418 / 180 ) * ($SkewHeight + 10) + $YPos + $SpliceHeight + 4;
2661          else
2662           $TY = sin(($TAngle) * 3.1418 / 180 ) * ($SkewHeight + 4) + $YPos - ($TextHeight/2);
2663
2664          if ( $TAngle > 90 && $TAngle < 270 )
2665           $TX = $TX - $TextWidth;

Stack Trace
#0
–
 /var/www/html/application/third_party/pchart/pChart.class.php(2653): imageftbbox(10, 0, "/var/www/html/fonts/DejaVuSans.ttf", "33%")

2648          elseif ($DrawLabels == PIE_LABELS)
2649           $Caption  = $iLabels[$Key];
2650          elseif ($DrawLabels == PIE_PERCENTAGE_LABEL)
2651           $Caption  = $iLabels[$Key]."\r\n".(round($Value * pow(10,$Decimals) * $SplicePercent)/pow(10,$Decimals))."%";
2652
2653          $Position   = imageftbbox($this->FontSize,0,$this->FontName,$Caption);
2654          $TextWidth  = $Position[2]-$Position[0];
2655          $TextHeight = abs($Position[1])+abs($Position[3]);
2656
2657          $TX = cos(($TAngle) * 3.1418 / 180 ) * ($Radius + 10)+ $XPos;
2658

 /var/www/html/index.php(194): CApplication->run()
2018-02-21 14:27:42 nginx/1.10.3 Yii Framework/1.1.18