tr1/ui/widgets/paginator: hide UI for empty text

This will automatically hide the paginator UI if the text content is
empty.

Resolves #2097.

docs/tr1/CHANGELOG.md

@@ -1,4 +1,5 @@
 ## [Unreleased](https://github.com/LostArtefacts/TRX/compare/tr1-4.7...develop) - ××××-××-××
+- changed the inventory examine UI to auto-hide if the item description is empty (#2097)
 - fixed falling pickup items not being drawn when they land in rare cases (#2088)
 - fixed unbinding keys not working for controllers (#2090, regression from 4.6)
 - fixed hiding game UI causing the reset progressbar UI element to not show (regression from 4.7)

docs/tr1/GAMEFLOW.md

@@ -325,7 +325,8 @@ Following are each of the properties available within a level.
       Players can examine items in the inventory when this text has been
       defined. Use <code>\n</code> in the text to create new lines; you can also
       use <code>\f</code> to force a page break. Long text will be automatically
-      wrapped and paginated as necessary.
+      wrapped and paginated as necessary. If an empty string is defined, the UI
+      will not be shown and the inventory item simply focussed instead.
     </td>
   </tr>
   <tr valign="top">

src/tr1/game/ui/widgets/paginator.c

@@ -36,6 +36,7 @@ typedef struct {
     UI_WIDGET *page_label;
     int32_t current_page;
     VECTOR *page_content;
+    bool shown;
 } UI_PAGINATOR;
 
 static void M_DoLayout(UI_PAGINATOR *self);
@@ -107,7 +108,7 @@ static void M_Control(UI_PAGINATOR *const self)
 
 static void M_Draw(UI_PAGINATOR *const self)
 {
-    if (self->window->draw != NULL) {
+    if (self->shown && self->window->draw != NULL) {
         self->window->draw(self->window);
     }
 }
@@ -149,6 +150,8 @@ UI_WIDGET *UI_Paginator_Create(
         .free = (UI_WIDGET_FREE)M_Free,
     };
 
+    self->shown = !String_IsEmpty(text);
+
     self->outer_stack = UI_Stack_Create(
         UI_STACK_LAYOUT_VERTICAL, UI_STACK_AUTO_SIZE, UI_STACK_AUTO_SIZE);