From e692460c6c9d0d8aea09ed914ce06a8fc8fe5524 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Tue, 29 May 2012 23:53:58 +0530
Subject: [PATCH] ...

---
 src/calibre/gui2/viewer/main.py | 10 ++++++++--
 src/calibre/gui2/viewer/toc.py  | 11 +++++++++--
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/calibre/gui2/viewer/main.py b/src/calibre/gui2/viewer/main.py
index 48927f0e4a..0ce6c3d48b 100644
--- a/src/calibre/gui2/viewer/main.py
+++ b/src/calibre/gui2/viewer/main.py
@@ -671,7 +671,9 @@ class EbookViewer(MainWindow, Ui_EbookViewer):
 
     def goto_next_section(self):
         if hasattr(self, 'current_index'):
-            entry = self.toc_model.next_entry(self.current_index)
+            entry = self.toc_model.next_entry(self.current_index,
+                    self.view.document.read_anchor_positions(),
+                    self.view.scroll_pos)
             if entry is not None:
                 self.pending_goto_next_section = (
                         self.toc_model.currently_viewed_entry, entry, False)
@@ -679,7 +681,9 @@ class EbookViewer(MainWindow, Ui_EbookViewer):
 
     def goto_previous_section(self):
         if hasattr(self, 'current_index'):
-            entry = self.toc_model.next_entry(self.current_index, backwards=True)
+            entry = self.toc_model.next_entry(self.current_index,
+                    self.view.document.read_anchor_positions(),
+                    self.view.scroll_pos, backwards=True)
             if entry is not None:
                 self.pending_goto_next_section = (
                         self.toc_model.currently_viewed_entry, entry, True)
@@ -699,6 +703,8 @@ class EbookViewer(MainWindow, Ui_EbookViewer):
                 # Check that we actually progressed
                 if pgns[0] is self.toc_model.currently_viewed_entry:
                     entry = self.toc_model.next_entry(self.current_index,
+                            self.view.document.read_anchor_positions(),
+                            self.view.scroll_pos,
                             backwards=pgns[2], current_entry=pgns[1])
                     if entry is not None:
                         self.pending_goto_next_section = (
diff --git a/src/calibre/gui2/viewer/toc.py b/src/calibre/gui2/viewer/toc.py
index bb0510471e..0cb4e5b22e 100644
--- a/src/calibre/gui2/viewer/toc.py
+++ b/src/calibre/gui2/viewer/toc.py
@@ -33,7 +33,7 @@ class TOCItem(QStandardItem):
         self.normal_font = self.font()
         for t in toc:
             self.appendRow(TOCItem(spine, t, depth+1, all_items, parent=self))
-        self.setFlags(Qt.ItemIsEnabled|Qt.ItemIsSelectable)
+        self.setFlags(Qt.ItemIsEnabled)
         spos = 0
         for i, si in enumerate(spine):
             if si == self.abspath:
@@ -131,14 +131,21 @@ class TOC(QStandardItemModel):
                 self.currently_viewed_entry = t
         return items_being_viewed
 
-    def next_entry(self, spine_pos, backwards=False, current_entry=None):
+    def next_entry(self, spine_pos, anchor_map, scroll_pos, backwards=False,
+            current_entry=None):
         current_entry = (self.currently_viewed_entry if current_entry is None
                 else current_entry)
         if current_entry is None: return
         items = reversed(self.all_items) if backwards else self.all_items
         found = False
+        top = scroll_pos[0]
         for item in items:
             if found:
+                start_pos = anchor_map.get(item.start_anchor, 0)
+                if backwards and item.is_being_viewed and start_pos >= top:
+                    # Going to this item will either not move the scroll
+                    # position or cause to to *increase* instead of descresing
+                    continue
                 if item.starts_at != spine_pos or item.start_anchor:
                     return item
             if item is current_entry: