restrict slider ui to slider fields

src/data/field/choice.hpp

@@ -33,13 +33,14 @@ public:
   class Choice;
   typedef intrusive_ptr<Choice> ChoiceP;
   
-  ChoiceP choices;        ///< A choice group of possible choices
+  ChoiceP choices;                          ///< A choice group of possible choices
-  OptionalScript script;      ///< Script to apply to all values
+  OptionalScript script;                    ///< Script to apply to all values
-  OptionalScript default_script;  ///< Script that generates the default value
+  OptionalScript default_script;            ///< Script that generates the default value
-  String initial;          ///< Initial choice of a new value, or ""
+  String initial;                           ///< Initial choice of a new value, or ""
-  String default_name;      ///< Name of "default" value
+  String default_name;                      ///< Name of "default" value
-  map<String,Color> choice_colors;      ///< Colors for the various choices (when color_cardlist)
+  map<String,Color> choice_colors;          ///< Colors for the various choices (when color_cardlist)
-  map<String,Color> choice_colors_cardlist;  ///< Colors for the various choices, for in the card list
+  map<String,Color> choice_colors_cardlist; ///< Colors for the various choices, for in the card list
+  bool is_slider = false;                   ///< Should the UI be displayed as a slider?
 
   void initDependencies(Context&, const Dependency&) const override;
   void after_reading(Version ver) override;

src/data/field/slider.cpp

@@ -35,6 +35,8 @@ IMPLEMENT_REFLECTION(SliderField) {
 void SliderField::after_reading(Version ver) {
   Field::after_reading(ver);
 
+  is_slider = true;
+
   int choice_count = choices->choices.size();
 
   if (maximum < minimum) swap(minimum, maximum);

src/gui/value/choice.cpp

@@ -202,27 +202,21 @@ DropDownChoiceList::DropDownChoiceList(Window* parent, bool is_submenu, ValueVie
   : DropDownChoiceListBase(parent, is_submenu, cve, group)
 {
   // determine if slider
-  size_t count = itemCount();
+  if (itemCount() > 1 && field().is_slider) {
-  if (count > 3) {
+    is_slider = true;
-    int value;
+    // load slider images if needed
-    try {
+    if (!slider_loaded) {
-      String first_item = capitalize(itemText(0));
+      slider_loaded = true;
-      if (first_item != _("Default")) value = std::stoi(first_item.ToStdString());
+      try {
-      value = std::stoi(itemText(1).ToStdString());
-      value = std::stoi(itemText(count - 2).ToStdString());
-      value = std::stoi(itemText(count - 1).ToStdString());
-      // the choices are numbers, use a slider
-      is_slider = true;
-      // load slider images if needed
-      if (!slider_loaded) {
-        slider_loaded = true;
         slider_left = load_resource_image(_("slider_left"));
         slider_right = load_resource_image(_("slider_right"));
         slider_center = load_resource_image(_("slider_center"));
         slider_tick = load_resource_image(_("slider_tick"));
       }
+      catch (...) {
+        throw InternalError(_("Can't load slider resources"));
+      }
     }
-    catch (...) {}
   }
 }