MDL-47494 ddmarker: Merge branch 'MOODLE_21_STABLE'

question/type/ddmarker/lang/en/qtype_ddmarker.php

@@ -33,6 +33,7 @@ $string['draggableitem'] = 'Draggable item';
 $string['draggableitemheader'] = 'Draggable item {$a}';
 $string['draggableitemtype'] = 'Type';
 $string['draggableword'] = 'Draggable text';
+$string['dropbackground'] = 'Background image for dragging markers onto';
 $string['dropzone'] = 'Drop zone {$a}';
 $string['dropzoneheader'] = 'Drop zones';
 $string['followingarewrong'] = 'The following markers have been placed in the wrong area : {$a}.';

question/type/ddmarker/renderer.php

@@ -49,7 +49,11 @@ class qtype_ddmarker_renderer extends qtype_ddtoimage_renderer_base {
 
         $bgimage = self::get_url_for_image($qa, 'bgimage');
 
-        $img = html_writer::empty_tag('img', array('src'=>$bgimage, 'class'=>'dropbackground'));
+        $img = html_writer::empty_tag('img',
+                                        array('src'=>$bgimage,
+                                        'class'=>'dropbackground',
+                                        'alt' => get_string('dropbackground', 'qtype_ddmarker')));
+
         $droparea = html_writer::tag('div', $img, array('class'=>'droparea'));
 
         $draghomes = '';