Change the method the document is rehighlighted. This is significantly faster

nw/gui/dialogs/configeditor.py

@@ -264,6 +264,7 @@ class GuiConfigEditGeneral(QWidget):
         guiDark         = self.guiDarkIcons.isChecked()
         spellTool       = self.spellToolList.currentData()
         spellLanguage   = self.spellLangList.currentData()
+        bigDocLimit     = self.spellBigDoc.value()
         autoSaveDoc     = self.autoSaveDoc.value()
         autoSaveProj    = self.autoSaveProj.value()
         backupPath      = self.projBackupPath.text()
@@ -278,6 +279,7 @@ class GuiConfigEditGeneral(QWidget):
         self.mainConf.guiDark         = guiDark
         self.mainConf.spellTool       = spellTool
         self.mainConf.spellLanguage   = spellLanguage
+        self.mainConf.bigDocLimit     = bigDocLimit
         self.mainConf.autoSaveDoc     = autoSaveDoc
         self.mainConf.autoSaveProj    = autoSaveProj
         self.mainConf.backupPath      = backupPath

nw/gui/elements/doceditor.py

@@ -304,9 +304,11 @@ class GuiDocEditor(QTextEdit):
         # Updating root frame triggers a QTextDocument->contentsChange
         # signal, which we do not want as it re-runs the syntax
         # highlighter and spell checker, so we block it briefly.
+        # We then emit a signal that does not trigger re-highlighting.
         self.qDocument.blockSignals(True)
         self.qDocument.rootFrame().setFrameFormat(docFormat)
         self.qDocument.blockSignals(False)
+        self.qDocument.contentsChange.emit(0,0,0)
 
         return
 
@@ -372,18 +374,26 @@ class GuiDocEditor(QTextEdit):
         self.theParent.mainMenu.setSpellCheck(theMode)
         self.theProject.setSpellCheck(theMode)
         self.hLight.setSpellCheck(theMode)
-        self.hLight.rehighlight()
+        self.reHighlightDocument()
 
         logger.verbose("Spell check is set to %s" % str(theMode))
 
         return True
 
-    def updateSpellCheck(self):
+    def reHighlightDocument(self):
         """Rerun the highlighter to update spell checking status of the
-        currently loaded text.
+        currently loaded text. The fastest way to do this, at least as
+        of Qt 5.13, is to clear the text and put it back.
         """
+
         if self.spellCheck:
-            self.hLight.rehighlight()
+            theText = self.getText()
+            self.clear()
+            bfTime = time()
+            self.setPlainText(theText)
+            afTime = time()
+            logger.debug("Document re-highlighted in %.3f milliseconds" % (1000*(afTime-bfTime)))
+
         return True
 
     ##
@@ -615,6 +625,9 @@ class GuiDocEditor(QTextEdit):
         return
 
     def _docChange(self, thePos, charsRemoved, charsAdded):
+        """Triggered by QTextDocument->contentsChanged. This also
+        triggers the syntax highlighter.
+        """
         self.lastEdit = time()
         if not self.docChanged:
             self.setDocumentChanged(True)

nw/gui/mainmenu.py

@@ -618,7 +618,7 @@ class GuiMainMenu(QMenuBar):
         self.aReRunSpell = QAction("Re-Run Spell Check", self)
         self.aReRunSpell.setStatusTip("Run the spell checker on current document")
         self.aReRunSpell.setShortcut("F7")
-        self.aReRunSpell.triggered.connect(self.theParent.docEditor.updateSpellCheck)
+        self.aReRunSpell.triggered.connect(self.theParent.docEditor.reHighlightDocument)
         self.toolsMenu.addAction(self.aReRunSpell)
 
         # Tools > Separator

nw/gui/tools/dochighlight.py

@@ -201,6 +201,11 @@ class GuiDocHighlighter(QSyntaxHighlighter):
     ##
 
     def highlightBlock(self, theText):
+        """Highlight a single block. Prefer to check first character for
+        all formats that are defined by their initial characters. This
+        is significantly faster than running the regex checks we use for
+        text paragraphs.
+        """
 
         if self.theHandle is None or not theText:
             return
@@ -224,6 +229,10 @@ class GuiDocHighlighter(QSyntaxHighlighter):
                         kwFmt.setUnderlineStyle(QTextCharFormat.SpellCheckUnderline)
                         self.setFormat(xPos, xLen, kwFmt)
 
+            # We never want to run the spell checker on keyword/values,
+            # so we force a return here
+            return
+
         elif theText.startswith("# "): # Header 1
             self.setFormat(0, 1, self.hStyles["header1"])
             self.setFormat(1, len(theText), self.hStyles["header1h"])
@@ -277,6 +286,10 @@ class GuiDocHighlighter(QSyntaxHighlighter):
     ##
 
     def _makeFormat(self, fmtCol=None, fmtStyle=None, fmtSize=None):
+        """Generate a valid character format to be applied to the text
+        that is to be highlighted.
+        """
+
         theFormat = QTextCharFormat()
 
         if fmtCol is not None: