From 43ce0fb44fac8a2bc9ac87686a73d806cf89e731 Mon Sep 17 00:00:00 2001
From: Lance Edgar <lance@edbob.org>
Date: Wed, 22 Nov 2017 11:21:59 -0600
Subject: [PATCH] Auto-scroll window as needed to ensure drop-down choices are
 visible

---
 tailbone/static/js/jquery.ui.tailbone.js | 15 ++++++++++-
 tailbone/static/js/tailbone.js           | 34 ++++++++++++++++++++++++
 tailbone/templates/deform/select.pt      | 13 ++++++++-
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/tailbone/static/js/jquery.ui.tailbone.js b/tailbone/static/js/jquery.ui.tailbone.js
index a5a4dadc..08908e74 100644
--- a/tailbone/static/js/jquery.ui.tailbone.js
+++ b/tailbone/static/js/jquery.ui.tailbone.js
@@ -58,6 +58,10 @@
                 }
             });
 
+            this.add_filter.on('selectmenuopen', function(event, ui) {
+                show_all_options($(this));
+            });
+
             // Intercept filters form submittal, and submit via AJAX instead.
             this.filters_form.on('submit', function() {
                 var settings = {filter: true, partial: true};
@@ -258,6 +262,10 @@
                 }
             });
 
+            this.verb_select.on('selectmenuopen', function(event, ui) {
+                show_all_options($(this));
+            });
+
             // Enhance any date values with datepicker widget.
             this.inputs.find('.value input[type="date"]').datepicker({
                 dateFormat: 'yy-mm-dd',
@@ -267,7 +275,12 @@
 
             // Enhance any choice/dropdown values with selectmenu.
             this.inputs.find('.value select').selectmenu({
-                width: '15em'
+                // TODO: don't remember why this was here, but seems unwanted
+                // width: '15em'
+            });
+
+            this.inputs.find('.value select').on('selectmenuopen', function(event, ui) {
+                show_all_options($(this));
             });
 
             // Listen for button click, to keep checkbox in sync.
diff --git a/tailbone/static/js/tailbone.js b/tailbone/static/js/tailbone.js
index 5b6e6d92..67f9a409 100644
--- a/tailbone/static/js/tailbone.js
+++ b/tailbone/static/js/tailbone.js
@@ -89,6 +89,37 @@ function dialog_button(event) {
 }
 
 
+/**
+ * Scroll screen as needed to ensure all options are visible, for the given
+ * select menu widget.
+ */
+function show_all_options(select) {
+    if (! select.is(':visible')) {
+        /*
+         * Note that the following code was largely stolen from
+         * http://brianseekford.com/2013/06/03/how-to-scroll-a-container-or-element-into-view-using-jquery-javascript-in-your-html/
+         */
+
+        var docViewTop = $(window).scrollTop();
+        var docViewBottom = docViewTop + $(window).height();
+
+        var widget = select.selectmenu('menuWidget');
+        var elemTop = widget.offset().top;
+        var elemBottom = elemTop + widget.height();
+
+        var isScrolled = ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
+
+        if (!isScrolled) {
+            if (widget.height() > $(window).height()) { //then just bring to top of the container
+                $(window).scrollTop(elemTop)
+            } else { //try and and bring bottom of container to bottom of screen
+                $(window).scrollTop(elemTop -  ($(window).height() - widget.height()));
+            }
+        }
+    }
+}
+
+
 /*
  * reference to existing timeout warning dialog, if any
  */
@@ -194,6 +225,9 @@ $(function() {
      * enhance dropdowns
      */
     $('select[auto-enhance="true"]').selectmenu();
+    $('select[auto-enhance="true"]').on('selectmenuopen', function(event, ui) {
+        show_all_options($(this));
+    });
 
     /* Also automatically disable any buttons marked for that. */
     $('a.button[disabled=disabled]').button('option', 'disabled', true);
diff --git a/tailbone/templates/deform/select.pt b/tailbone/templates/deform/select.pt
index 5bae0ecb..1fe8dade 100644
--- a/tailbone/templates/deform/select.pt
+++ b/tailbone/templates/deform/select.pt
@@ -17,7 +17,7 @@
           class string: form-control ${css_class or ''};
           multiple multiple;
           size size;
-          style style;" auto-enhance="true">
+          style style;">
     <tal:loop tal:repeat="item values">
       <optgroup tal:condition="isinstance(item, optgroup_class)"
                 tal:attributes="label item.label">
@@ -38,4 +38,15 @@
   </select>
   <input type="hidden" name="__end__" value="${name}:sequence"
          tal:condition="multiple" />
+  <script type="text/javascript">
+    deform.addCallback(
+      '${oid}',
+      function(oid) {
+          $('#' + oid).selectmenu();
+          $('#' + oid).on('selectmenuopen', function(event, ui) {
+              show_all_options($(this));
+          });
+      }
+    );
+  </script>
 </div>