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124 lines
4.2 KiB
124 lines
4.2 KiB
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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require_once('../../../../config.php');
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$id = required_param('id', PARAM_INT);
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$PAGE->set_url('/mod/feedback/item/captcha/print_captcha.php', array('id'=>$id));
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if ($id) {
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if (! $cm = get_coursemodule_from_id('feedback', $id)) {
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print_error('invalidcoursemodule');
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}
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if (! $course = $DB->get_record("course", array("id"=>$cm->course))) {
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print_error('coursemisconf');
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}
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if (! $feedback = $DB->get_record("feedback", array("id"=>$cm->instance))) {
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print_error('invalidcoursemodule');
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}
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}
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if (!isset($SESSION->feedback->item->captcha)) {
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print_error('captchanotset', 'feedback');
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}
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$height = 40;
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$charcount = $SESSION->feedback->item->captcha->charcount;
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$fontfile = $CFG->libdir.'/default.ttf';
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$ttfbox = imagettfbbox ( 30, 0, $fontfile, 'H' );//the text to measure
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$charwidth = $ttfbox[2];
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$width = $charcount * $charwidth;
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$scale = 0.3;
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$elipsesize = intval((($width + $height)/2) / 5);
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$factor_x = intval($width * $scale);
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$factor_y = intval($height * $scale);
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//I split the colors in three ranges
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//given are the max-min-values
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$colors = array(array(0, 40), array(50, 200), array(210, 255));
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list($col_text1, $col_el, $col_text2) = $colors;
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//if the text is in color_1 so the elipses can be in color_2 or color_3
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//if the text is in color_2 so the elipses can be in color_1 or color_3
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//and so on.
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$textcolnum = rand(1, 3);
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//create the numbers to print out
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$nums = array();
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for ($i = 0; $i < $charcount; $i++) {
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$nums[] = rand(0, 9); //Ziffern von 0-
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}
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//to draw enough elipses so I draw 0.2 * width and 0.2 * height
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//we need th colors for that
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$properties = array();
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for ($x = 0; $x < $factor_x; $x++) {
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for ($y = 0; $y < $factor_y; $y++) {
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$propobj = new stdClass();
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$propobj->x = intval($x / $scale);
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$propobj->y = intval($y / $scale);
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$propobj->red = get_random_color($col_el[0], $col_el[1]);
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$propobj->green = get_random_color($col_el[0], $col_el[1]);
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$propobj->blue = get_random_color($col_el[0], $col_el[1]);
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$properties[] = $propobj;
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}
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}
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shuffle($properties);
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// create a blank image
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$image = imagecreatetruecolor($width, $height);
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$bg = imagecolorallocate($image, 0, 0, 0);
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for ($i = 0; $i < ($factor_x * $factor_y); $i++) {
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$propobj = $properties[$i];
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// choose a color for the ellipse
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$col_ellipse = imagecolorallocate($image, $propobj->red, $propobj->green, $propobj->blue);
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// draw the white ellipse
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imagefilledellipse($image, $propobj->x, $propobj->y, $elipsesize, $elipsesize, $col_ellipse);
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}
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$checkchar = '';
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for ($i = 0; $i < $charcount; $i++) {
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$colnum = rand(1, 2);
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$textcol = new stdClass();
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$textcol->red = get_random_color(${'col_text'.$colnum}[0], ${'col_text'.$colnum}[1]);
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$textcol->green = get_random_color(${'col_text'.$colnum}[0], ${'col_text'.$colnum}[1]);
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$textcol->blue = get_random_color(${'col_text'.$colnum}[0], ${'col_text'.$colnum}[1]);
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$color_text = imagecolorallocate($image, $textcol->red, $textcol->green, $textcol->blue);
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$angle_text = rand(-20, 20);
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$left_text = $i * $charwidth;
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$text = $nums[$i];
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$checkchar .= $text;
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imagettftext($image, 30, $angle_text, $left_text, 35, $color_text, $fontfile, $text);
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}
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$SESSION->feedback->item->captcha->checkchar = $checkchar;
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// output the picture
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header("Content-type: image/png");
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imagepng($image);
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function get_random_color($val1 = 0, $val2 = 255) {
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$min = $val1 < $val2 ? $val1 : $val2;
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$max = $val1 > $val2 ? $val1 : $val2;
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return rand($min, $max);
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}
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