From 1d4a0cd24bfdea82e8e70aa0ad9a82679447f4d9 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 20 Apr 2014 11:06:36 +0530
Subject: [PATCH] Spell check: Improve performance of scrolling through the
 word list using arrow keys by not updating the list of suggestions
 immediately

---
 src/calibre/gui2/tweak_book/spell.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index 4fced9a6cf..06a277e996 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -807,6 +807,9 @@ class SpellCheck(Dialog):
         self.thread = None
         self.cancel = False
         dictionaries.initialize()
+        self.current_word_changed_timer = t = QTimer()
+        t.timeout.connect(self.do_current_word_changed)
+        t.setSingleShot(True), t.setInterval(100)
         Dialog.__init__(self, _('Check spelling'), 'spell-check', parent)
         self.work_finished.connect(self.work_done, type=Qt.QueuedConnection)
         self.setAttribute(Qt.WA_DeleteOnClose, False)
@@ -960,6 +963,9 @@ class SpellCheck(Dialog):
         self.user_dictionaries_missing_label.setVisible(not self.user_dictionaries.isVisible())
 
     def current_word_changed(self, *args):
+        self.current_word_changed_timer.start(self.current_word_changed_timer.interval())
+
+    def do_current_word_changed(self):
         try:
             b = self.ignore_button
         except AttributeError: