}
$line->y_order = array('allusers');
if ($groups) {
foreach (array_keys($groups) as $group) {
$useridingroup = get_users_by_capability($modcontext, array('mod/quiz:reviewmyattempts', 'mod/quiz:attempt'), '', '', '', '', $group, '', false);
if ($useridingroup) {
$useridingrouplist = join(',', array_keys($useridingroup));
$groupdata = quiz_report_grade_bands($bandwidth, $bands, $quizid, $useridingrouplist);
if ($groupdata) {
$line->parameter['bar_size'] = 1.2;
$line->y_data['groupusers' . $group] = $groupdata;
//only turn on legends if there is more than one set of bars
$line->parameter['legend'] = 'outside-top';
$line->parameter['legend_border'] = 'black';
$line->parameter['legend_offset'] = 4;
$line->y_format['groupusers' . $group] = array('colour' => graph_get_new_colour(), 'bar' => 'fill', 'shadow_offset' => 1, 'legend' => groups_get_group_name($group));
$line->y_order[] = 'groupusers' . $group;
}
}
}
}
$line->parameter['y_min_left'] = 0;
// start at 0
$line->parameter['y_max_left'] = max($line->y_data['allusers']);
$line->parameter['y_decimal_left'] = 0;
// 2 decimal places for y axis.
//pick a sensible number of gridlines depending on max value on graph.
$gridlines = max($line->y_data['allusers']);
while ($gridlines >= 10) {
if ($gridlines >= 50) {
$gridlines = $gridlines / 5;
$line->parameter['y_label_left'] = '%';
$line->parameter['x_label'] = get_string('position', 'quiz_statistics');
$line->parameter['y_label_angle'] = 90;
$line->parameter['x_label_angle'] = 0;
$line->parameter['x_axis_angle'] = 60;
$line->parameter['legend'] = 'outside-right';
$line->parameter['legend_border'] = 'black';
$line->parameter['legend_offset'] = 4;
$line->parameter['bar_size'] = 1;
$line->parameter['zero_axis'] = 'grayEE';
$fieldstoplot = array('facility' => get_string('facility', 'quiz_statistics'), 'discriminativeefficiency' => get_string('discriminative_efficiency', 'quiz_statistics'));
$fieldstoplotfactor = array('facility' => 100, 'discriminativeefficiency' => 1);
$line->x_data = array();
foreach (array_keys($fieldstoplot) as $fieldtoplot) {
$line->y_data[$fieldtoplot] = array();
$line->y_format[$fieldtoplot] = array('colour' => graph_get_new_colour(), 'bar' => 'fill', 'shadow_offset' => 1, 'legend' => $fieldstoplot[$fieldtoplot]);
}
foreach ($questionstatistics as $questionstatistic) {
$line->x_data[$questions[$questionstatistic->questionid]->number] = $questions[$questionstatistic->questionid]->number;
foreach (array_keys($fieldstoplot) as $fieldtoplot) {
$value = !is_null($questionstatistic->{$fieldtoplot}) ? $questionstatistic->{$fieldtoplot} : 0;
$value = $value * $fieldstoplotfactor[$fieldtoplot];
$line->y_data[$fieldtoplot][$questions[$questionstatistic->questionid]->number] = $value;
}
}
foreach (array_keys($line->y_data) as $fieldtoplot) {
ksort($line->y_data[$fieldtoplot]);
$line->y_data[$fieldtoplot] = array_values($line->y_data[$fieldtoplot]);
}
ksort($line->x_data);
$line->x_data = array_values($line->x_data);
$graph->parameter['zero_axis'] = 'grayEE';
// Configure what to display.
$fieldstoplot = array(
'facility' => get_string('facility', 'quiz_statistics'),
'discriminativeefficiency' => get_string('discriminative_efficiency', 'quiz_statistics')
);
$fieldstoplotfactor = array('facility' => 100, 'discriminativeefficiency' => 1);
// Prepare the arrays to hold the data.
$xdata = array();
foreach (array_keys($fieldstoplot) as $fieldtoplot) {
$ydata[$fieldtoplot] = array();
$graph->y_format[$fieldtoplot] = array(
'colour' => graph_get_new_colour(),
'bar' => 'fill',
'shadow_offset' => 1,
'legend' => $fieldstoplot[$fieldtoplot]
);
}
// Fill in the data for each question.
foreach ($questionstatistics as $questionstatistic) {
$number = $questions[$questionstatistic->slot]->number;
$xdata[$number] = $number;
foreach ($fieldstoplot as $fieldtoplot => $notused) {
$value = $questionstatistic->$fieldtoplot;
if (is_null($value)) {
$value = 0;
