writer_epub: Add <spine page-progression-direction=rtl> option as page_progression_direction_rtl

calibre-plugin/plugin-defaults.ini

@@ -1416,6 +1416,10 @@ remove_transparency: true
 ## under [defaults] or [epub].
 #force_update_epub_always:false
 
+## Mark epub as having right-to-left page progression direction.
+## Useful for RtL languages such as Japanese.
+#page_progression_direction_rtl:false
+
 [html]
 
 ## include images from img tags in the body and summary of

fanficfare/configurable.py

@@ -287,6 +287,7 @@ def get_valid_set_options():
 
                'calibre_series_meta':(None,['epub'],boollist),
                'force_update_epub_always':(None,['epub'],boollist),
+               'page_progression_direction_rtl':(None,['epub'],boollist),
 
                'windows_eol':(None,['txt'],boollist),
 
@@ -461,6 +462,7 @@ def get_valid_keywords():
                  'logpage_at_end',
                  'calibre_series_meta',
                  'force_update_epub_always',
+                 'page_progression_direction_rtl',
                  'include_subject_tags',
                  'include_titlepage',
                  'include_tocpage',

fanficfare/defaults.ini

@@ -1404,6 +1404,10 @@ remove_transparency: true
 ## under [defaults] or [epub].
 #force_update_epub_always:false
 
+## Mark epub as having right-to-left page progression direction.
+## Useful for RtL languages such as Japanese.
+#page_progression_direction_rtl:false
+
 [html]
 
 ## include images from img tags in the body and summary of

fanficfare/writers/writer_epub.py

@@ -815,6 +815,8 @@ div { margin: 0pt; padding: 0pt; }
 
 
         spine = newTag(contentdom,"spine",attrs={"toc":"ncx"})
+        if self.getConfig('page_progression_direction_rtl'):
+            spine.setAttribute("page-progression-direction","rtl")
         package.appendChild(spine)
         for itemref in itemrefs:
             spine.appendChild(newTag(contentdom,"itemref",