FB2 footnotes: handle them just as other footnotes

- FB2 footnotes are no more rendered in-page by default
- In-page rendering can be enable by the added Style tweak
- FB2 footnotes can also show in footnote popup (with
  some added not-so-nice CSS so MuPDF can render them
  as crengine)

frontend/apps/reader/modules/readerlink.lua

@@ -1000,13 +1000,15 @@ function ReaderLink:showAsFootnotePopup(link, neglect_current_location)
         -- if not trusted, checks marked (*) don't apply
         flags = flags + 0x0002
     end
+    -- Checks for private CSS properties "-cr-hint: footnote/noteref/..." are
+    -- always done (they can be applied to specific elements or classe names
+    -- with Styles tweaks.)
 
     -- Trust role= and epub:type= attribute values if defined, for source(*) and target
-    -- (If needed, we could add a check for a private CSS property "-cr-hint: footnote"
-    -- or "-cr-hint: noteref", so one can define it to specific classes with Styles
-    -- tweaks.)
     flags = flags + 0x0004
-    -- flags = flags + 0x0008 -- Unused yet
+
+    -- Accept classic FB2 footnotes: body[name="notes" or "comments"] > section
+    flags = flags + 0x0008
 
     -- TARGET STATUS AND SOURCE RELATION
     -- Target must have an anchor #id (ie: must not be a simple link to a html file)

frontend/ui/data/css_tweaks.lua

@@ -613,6 +613,22 @@ This is just an example, that will need to be adapted into a user style tweak.]]
         },
         {
             title = _("In-page footnotes"),
+            {
+                id = "footnote-inpage_fb2";
+                title = _("In-page FB2 footnotes"),
+                description = _([[
+Show FB2 footnote text at the bottom of pages that contain links to them.]]),
+                -- (fb2.css already set font-size to 70% - so no need for a "smaller" variant)
+                css = [[
+body[name="notes"] section,
+body[name="comments"] section
+{
+    -cr-hint: footnote-inpage;
+    margin: 0 !important;
+}
+                ]],
+                separator = true,
+            },
             {
                 id = "footnote-inpage_epub";
                 title = _("In-page EPUB footnotes"),

frontend/ui/widget/footnotewidget.lua

@@ -89,6 +89,21 @@ body > li { list-style-type: none; }
 
 /* Remove any (possibly multiple) backlinks in Wikipedia EPUBs footnotes */
 .noprint { display: none; }
+
+/* Attempt to display FB2 footnotes as expected (as crengine does, putting
+ * the footnote number on the same line as the first paragraph via its
+ * support of "display: run-in" and a possibly added autoBoxing element) */
+body > section > autoBoxing > *,
+body > section > autoBoxing > title > *,
+body > section > title,
+body > section > title > p,
+body > section > p {
+    display: inline;
+}
+body > section > autoBoxing + p,
+body > section > p + p {
+    display: block;
+}
 ]]
 
 -- Add this if needed for debugging: