From adf0eb8e7d7ddbc12efa0ec58af76a9b471ab72c Mon Sep 17 00:00:00 2001
From: GRiker <griker@hotmail.com>
Date: Thu, 9 Aug 2012 07:40:44 -0600
Subject: [PATCH] Fine-tuned prefix layout for MOBI

---
 src/calibre/ebooks/oeb/transforms/jacket.py   |  1 +
 .../library/catalogs/epub_mobi_builder.py     | 23 +++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/calibre/ebooks/oeb/transforms/jacket.py b/src/calibre/ebooks/oeb/transforms/jacket.py
index f0610382b3..02abda0927 100644
--- a/src/calibre/ebooks/oeb/transforms/jacket.py
+++ b/src/calibre/ebooks/oeb/transforms/jacket.py
@@ -194,6 +194,7 @@ def render_jacket(mi, output_profile,
                 args[key] = escape(val)
                 args[key+'_label'] = escape(display_name)
             except:
+                # if the val (custom column contents) is None, don't add to args
                 pass
 
         if False:
diff --git a/src/calibre/library/catalogs/epub_mobi_builder.py b/src/calibre/library/catalogs/epub_mobi_builder.py
index 1c79901037..a81409ffc7 100644
--- a/src/calibre/library/catalogs/epub_mobi_builder.py
+++ b/src/calibre/library/catalogs/epub_mobi_builder.py
@@ -3252,17 +3252,22 @@ Author '{0}':
 
     def formatPrefix(self,prefix_char,soup):
         # Generate the HTML for the prefix portion of the listing
-        spanTag = Tag(soup, "span")
-        if prefix_char is None:
-            spanTag['style'] = "color:white"
-            spanTag.insert(0,NavigableString(self.defaultPrefix))
-            # 2e3a is 'two-em dash', which matches width in Kindle Previewer
-            # too wide in calibre viewer
-            # minimal visual distraction
-            # spanTag.insert(0,NavigableString(u'\u2e3a'))
+        # Kindle Previewer doesn't properly handle style=color:white
+        # MOBI does a better job allocating blank space with <code>
+        if self.opts.fmt == 'mobi':
+            codeTag = Tag(soup, "code")
+            if prefix_char is None:
+                codeTag.insert(0,NavigableString('&nbsp;'))
+            else:
+                codeTag.insert(0,NavigableString(prefix_char))
+            return codeTag
         else:
+            spanTag = Tag(soup, "span")
+            if prefix_char is None:
+                spanTag['style'] = "color:white"
+                prefix_char = self.defaultPrefix
             spanTag.insert(0,NavigableString(prefix_char))
-        return spanTag
+            return spanTag
 
     def generateAuthorAnchor(self, author):
         # Strip white space to ''