MDL-42031 assginfeedback_editpdf: fix next/previous/select page

mod/assign/feedback/editpdf/classes/document_services.php

@@ -380,7 +380,25 @@ class document_services {
                 // Image files are stale - regenerate them.
                 $files = array();
             } else {
-                return $files;
+
+                // Need to reorder the files following their name.
+                // because get_directory_files() return a different order than generate_page_images_for_attempt().
+                $orderedfiles = array();
+                foreach($files as $file) {
+                    // Extract the page number from the file name image_pageXXXX.png.
+                    preg_match('/page([\d]+)\./', $file->get_filename(), $matches);
+                    if (empty($matches) or !is_numeric($matches[1])) {
+                        throw new \coding_exception("'" . $file->get_filename()
+                            . "' file hasn't the expected format filename: image_pageXXXX.png.");
+                    }
+                    $pagenumber = (int)$matches[1];
+
+                    // Save the page in the ordered array.
+                    $orderedfiles[$pagenumber] = $file;
+                }
+                ksort($orderedfiles);
+
+                return $orderedfiles;
             }
         }
         return self::generate_page_images_for_attempt($assignment, $userid, $attemptnumber);

mod/assign/feedback/editpdf/yui/src/editor/js/editor.js

@@ -298,11 +298,11 @@ EDITOR.prototype = {
 
                 this.refresh_button_state();
             }
+
+            this.load_all_pages();
         }
         this.dialogue.centerDialogue();
         this.dialogue.show();
-
-        this.load_all_pages();
     },
 
     /**