FPDF::fillText, fillText in a rectangular area

FillText.php

<?php
    /** 
     * Fill text in a rectangular area
     *
     * It will automatically decrease font size if it exceeds the boundary.
     * It also takes cMargin into consideration.
     *
     * @see FPDF::Cell()
     *
     * @param  string $text
     * @param  number $x
     * @param  number $y
     * @param  number $w
     * @param  number $h
     * @param  string $align
     * @param  string $link
     */
    public function fillText($text, $x, $y, $w, $h, $align = 'C', $link = '') 
    {   
        // remove margins
        $width_without_margin = $w - 2 * $this->cMargin;

        // save the old font size so that we can revert it back
        $old_font_size = $font_size = $this->FontSizePt;

        // get the initial text width
        $text_width = $this->GetStringWidth($text);

        // only decrease font size if it exceeds the boundary
        if ($text_width > $width_without_margin) {

            do {
                $font_size--;
                $this->SetFontSize($font_size);
                $text_width = $this->GetStringWidth($text);
            } while ($text_width > $width_without_margin);

            // adjust x
            if ($align == 'R') {
                $x = $x + $w - $text_width - 2 * $this->cMargin;
            } else if ($align == 'C') {
                $x = $x + $w / 2 - $text_width / 2 - $this->cMargin;
            }   

            $w = $text_width + 2 * $this->cMargin;
        }   

        // draw text
        $this->SetXY($x, $y);
        // $this->Cell($w, $h, $text, 1, 0, $align, false, $link);
        $this->Cell($w, $h, $text, 0, 0, $align, false, $link);

        // revert back
        $this->SetFontSize($old_font_size);
    }