function getTextWidth( $size, $text )
    {
        // this function should not change any of the settings, though it will need to
        // track any directives which change during calculation, so copy them at the start
        // and put them back at the end.
        $this->pushTextState( $this->currentTextState );

        if (!$this->numFonts)
        {
            $this->selectFont('./fonts/Helvetica');
        }

        // converts a number or a float to a string so it can get the width
        $text = "$text";
        // hmm, this is where it all starts to get tricky - use the font information to
        // calculate the width of each character, add them up and convert to user units
        $w = 0;
        $len = strlen( $text );
        $cf = $this->currentFont;
        for ( $i = 0; $i < $len; $i++ )
        {
            $f = 1;
            $directiveArray = $this->PRVTcheckTextDirective( $text, $i, $f );
            $directive = $directiveArray['directive'];
            if ( $directive )
            {
                if ($f)
                {
                    $this->setCurrentFont();
                    $cf = $this->currentFont;
                }
                $i = $i + $directive-1;
            }
            else
            {
                $char = ord( $text[$i] );
                if ( isset($this->fonts[$cf]['differences'][$char] ) )
                {
                    // then this character is being replaced by another
                    $name = $this->fonts[$cf]['differences'][$char];
                    if ( isset($this->fonts[$cf]['C'][$name]['WX'] ) )
                    {
                        $w += $this->fonts[$cf]['C'][$name]['WX'];
                    }
                }
                else if ( isset($this->fonts[$cf]['C'][$char]['WX'] ) )
                {
                    $w += $this->fonts[$cf]['C'][$char]['WX'];
                }
                else
                {
                    $w += 700;
                }
            }
        }

        $this->popTextState();
        $this->setCurrentFont();

        return $w*$size/1000;
    }