Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * pdf data format writer

 *

 * @package    dataformat_pdf

 * @copyright  2019 Shamim Rezaie <shamim@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

namespace dataformat_pdf;

defined('MOODLE_INTERNAL') || die();

/**

 * pdf data format writer

 *

 * @package    dataformat_pdf

 * @copyright  2019 Shamim Rezaie <shamim@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class writer extends \core\dataformat\base {

    public $mimetype = "application/pdf";

    public $extension = ".pdf";

    /**

     * @var \pdf The pdf object that is used to generate the pdf file.

     */

    protected $pdf;

    /**

     * @var float Each column's width in the current sheet.

     */

    protected $colwidth;

    /**

     * @var string[] Title of columns in the current sheet.

     */

    protected $columns;

    /**

     * writer constructor.

     */

    public function __construct() {

        global $CFG;

        require_once($CFG->libdir . '/pdflib.php');

        $this->pdf = new \pdf();

        $this->pdf->setPrintHeader(false);

        $this->pdf->SetFooterMargin(PDF_MARGIN_FOOTER);

        // Set background color for headings.

        $this->pdf->SetFillColor(238, 238, 238);

    }

    public function send_http_headers() {

    }

    /**

     * Start output to file, note that the actual writing of the file is done in {@see close_output_to_file()}

     */

    public function start_output_to_file(): void {

        $this->start_output();

    }

    public function start_output() {

        $this->pdf->AddPage('L');

    }

    public function start_sheet($columns) {

        $margins = $this->pdf->getMargins();

        $pagewidth = $this->pdf->getPageWidth() - $margins['left'] - $margins['right'];

        $this->colwidth = $pagewidth / count($columns);

        $this->columns = $columns;

        $this->print_heading($this->pdf);

    }

    /**

     * Method to define whether the dataformat supports export of HTML

     *

     * @return bool

     */

    public function supports_html(): bool {

        return true;

    }

    /**

     * When exporting images, we need to return their Base64 encoded content. Otherwise TCPDF will create a HTTP

     * request for them, which will lead to the login page (i.e. not the image it expects) and throw an exception

     *

     * Note: ideally we would copy the file to a temp location and return it's path, but a bug in TCPDF currently

     * prevents that

     *

     * @param \stored_file $file

     * @return string|null

     */

    protected function export_html_image_source(\stored_file $file): ?string {

        // Set upper dimensions for embedded images.

        $resizedimage = $file->resize_image(400, 300);

        return '@' . base64_encode($resizedimage);

    }

    /**

     * Write a single record

     *

     * @param array $record

     * @param int $rownum

     */

    public function write_record($record, $rownum) {

        $rowheight = 0;

        $record = $this->format_record($record);

        foreach ($record as $cell) {

            // We need to calculate the row height (accounting for any content). Unfortunately TCPDF doesn't provide an easy

            // method to do that, so we create a second PDF inside a transaction, add cell content and use the largest cell by

            // height. Solution similar to that at https://stackoverflow.com/a/1943096.

            $pdf2 = clone $this->pdf;

            $pdf2->startTransaction();

            $numpages = $pdf2->getNumPages();

            $pdf2->AddPage('L');

            $this->print_heading($pdf2);

            $pdf2->writeHTMLCell($this->colwidth, 0, '', '', $cell, 1, 1, false, true, 'L');

            $pagesadded = $pdf2->getNumPages() - $numpages;

            $margins = $pdf2->getMargins();

            $pageheight = $pdf2->getPageHeight() - $margins['top'] - $margins['bottom'];

            $cellheight = ($pagesadded - 1) * $pageheight + $pdf2->getY() - $margins['top'] - $this->get_heading_height();

            $rowheight = max($rowheight, $cellheight);

            $pdf2->rollbackTransaction();

        }

        $margins = $this->pdf->getMargins();

        if ($this->pdf->getNumPages() > 1 &&

                ($this->pdf->GetY() + $rowheight + $margins['bottom'] > $this->pdf->getPageHeight())) {

            $this->pdf->AddPage('L');

            $this->print_heading($this->pdf);

        }

        // Get the last key for this record.

        end($record);

        $lastkey = key($record);

        // Reset the record pointer.

        reset($record);

        // Loop through each element.

        foreach ($record as $key => $cell) {

            // Determine whether we're at the last element of the record.

            $nextposition = ($lastkey === $key) ? 1 : 0;

            // Write the element.

            $this->pdf->writeHTMLCell($this->colwidth, $rowheight, '', '', $cell, 1, $nextposition, false, true, 'L');

        }

    }

    public function close_output() {

        $filename = $this->filename . $this->get_extension();

        $this->pdf->Output($filename, 'D');

    }

    /**

     * Write data to disk

     *

     * @return bool

     */

    public function close_output_to_file(): bool {

        $this->pdf->Output($this->filepath, 'F');

        return true;

    }

    /**

     * Prints the heading row for a given PDF.

     *

     * @param \pdf $pdf A pdf to print headings in

     */

    private function print_heading(\pdf $pdf) {

        $fontfamily = $pdf->getFontFamily();

        $fontstyle = $pdf->getFontStyle();

        $pdf->SetFont($fontfamily, 'B');

        $total = count($this->columns);

        $counter = 1;

        foreach ($this->columns as $columns) {

            $nextposition = ($counter == $total) ? 1 : 0;

            $pdf->Multicell($this->colwidth, $this->get_heading_height(), $columns, 1, 'C', true, $nextposition);

            $counter++;

        }

        $pdf->SetFont($fontfamily, $fontstyle);

    }

    /**

     * Returns the heading height.

     *

     * @return int

     */

    private function get_heading_height() {

        $height = 0;

        foreach ($this->columns as $columns) {

            $height = max($height, $this->pdf->getStringHeight($this->colwidth, $columns, false, true, '', 1));

        }

        return $height;

    }

}