function addCols( $tab )
{
        global $colonnes;

        $r1  = 10;
        $r2  = $this->w - ($r1 * 2) ;
        $y1  = 100;
        $y2  = $this->h - 50 - $y1;
        $this->SetXY( $r1, $y1 );
        //$this->RoundedRect($x, $y, $w, $h, 3.5, 'D');
        $this->RoundedRect( $r1, $y1, $r2, $y2, 3.5, "D");
        $this->Line( $r1, $y1+6, $r1+$r2, $y1+6);
        $colX = $r1;
        $colonnes = $tab;

        //while ( list( $lib, $pos ) = each ($tab) )
        for($i = 0; list( $lib, $pos ) = $tab[$i]; $i < count($tab); $i++; list( $lib, $pos ) = $tab[$i])
        {
                $this->SetXY( $colX, $y1+2 );
                $this->Cell( $pos, 1, $lib, 0, 0, "C");
                $colX += $pos;
                $this->Line( $colX, $y1, $colX, $y1+$y2);
        }
}