create a double column graph in fpdf php - php

Question

I'm creating a graph in fpdf and I saw this question and it is exactly the same as what I need but when I copied it on my report-weekly.php file it doesn't work and gave me an error message of
Notice: Undefined offset: 0 in C:\xampp\htdocs\qtqt\asd\report-weekly.php on line 112
Notice: Undefined offset: 1 in C:\xampp\htdocs\qtqt\asd\report-weekly.php on line 112
Notice: Undefined offset: 2 in C:\xampp\htdocs\qtqt\asd\report-weekly.php on line 112
FPDF error: Some data has already been output, can't send PDF file
this is the code I copied
<?php
require('diag/sector.php');
class PDF_Diag extends PDF_Sector {
var $legends;
var $wLegend;
var $sum;
var $NbVal;
function ColumnChart($w, $h, $data, $format, $color=null, $maxVal=0, $nbDiv=4)
{
// RGB for color 0
$colors[0][0] = 155;
$colors[0][1] = 75;
$colors[0][2] = 155;
// RGB for color 1
$colors[1][0] = 0;
$colors[1][1] = 155;
$colors[1][2] = 0;
// RGB for color 2
$colors[2][0] = 75;
$colors[2][1] = 155;
$colors[2][2] = 255;
// RGB for color 3
$colors[3][0] = 75;
$colors[3][1] = 0;
$colors[3][2] = 155;
$this->SetFont('Courier', '', 10);
$this->SetLegends($data,$format);
// Starting corner (current page position where the chart has been inserted)
$XPage = $this->GetX();
$YPage = $this->GetY();
$margin = 2;
// Y position of the chart
$YDiag = $YPage + $margin;
// chart HEIGHT
$hDiag = floor($h - $margin * 2);
// X position of the chart
$XDiag = $XPage + $margin;
// chart LENGHT
$lDiag = floor($w - $margin * 3 - $this->wLegend);
if($color == null)
$color=array(155,155,155);
if ($maxVal == 0)
{
foreach($data as $val)
{
if(max($val) > $maxVal)
{
$maxVal = max($val);
}
}
}
// define the distance between the visual reference lines (the lines which cross the chart's internal area and serve as visual reference for the column's heights)
$valIndRepere = ceil($maxVal / $nbDiv);
// adjust the maximum value to be plotted (recalculate through the newly calculated distance between the visual reference lines)
$maxVal = $valIndRepere * $nbDiv;
// define the distance between the visual reference lines (in milimeters)
$hRepere = floor($hDiag / $nbDiv);
// adjust the chart HEIGHT
$hDiag = $hRepere * $nbDiv;
// determine the height unit (milimiters/data unit)
$unit = $hDiag / $maxVal;
// determine the bar's thickness
$lBar = floor($lDiag / ($this->NbVal + 1));
$lDiag = $lBar * ($this->NbVal + 1);
$eColumn = floor($lBar * 80 / 100);
// draw the chart border
$this->SetLineWidth(0.2);
$this->Rect($XDiag, $YDiag, $lDiag, $hDiag);
$this->SetFont('Courier', '', 10);
$this->SetFillColor($color[0],$color[1],$color[2]);
$i=0;
foreach($data as $val)
{
//Column
$yval = $YDiag + $hDiag;
$xval = $XDiag + ($i + 1) * $lBar - $eColumn/2;
$lval = floor($eColumn/(count($val)));
$j=0;
foreach($val as $v)
{
$hval = (int)($v * $unit);
$this->SetFillColor($colors[$j][0], $colors[$j][1], $colors[$j][2]);
$this->Rect($xval+($lval*$j), $yval, $lval, -$hval, 'DF');
$j++;
}
//Legend
$this->SetXY($xval, $yval + $margin);
$this->Cell($lval, 5, $this->legends[$i],0,0,'C');
$i++;
}
//Scales
for ($i = 0; $i <= $nbDiv; $i++)
{
$ypos = $YDiag + $hRepere * $i;
$this->Line($XDiag, $ypos, $XDiag + $lDiag, $ypos);
$val = ($nbDiv - $i) * $valIndRepere;
$ypos = $YDiag + $hRepere * $i;
$xpos = $XDiag - $margin - $this->GetStringWidth($val);
$this->Text($xpos, $ypos, $val);
}
}
function SetLegends($data, $format)
{
$this->legends=array();
$this->wLegend=0;
$this->NbVal=count($data);
}
}
$pdf = new PDF_Diag();
$pdf->AddPage();
$data[0] = array(470, 490, 90);
$data[1] = array(450, 530, 110);
$data[2] = array(420, 580, 100);
// Column chart
$pdf->SetFont('Arial', 'BIU', 12);
$pdf->Cell(210, 5, 'Chart Title', 0, 1, 'C');
$pdf->Ln(8);
$valX = $pdf->GetX();
$valY = $pdf->GetY();
$pdf->ColumnChart(110, 100, $data, null, array(255,175,100));
//$pdf->SetXY($valX, $valY);
$pdf->Output();
?>