TextEditors: Avoid multiple highlighting runs when changing font setting

And remove some unnecessary code in Python editor

Change-Id: I86cde74c244a16d1b36b0ac0e841ef8110ba832f
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/cppeditor/cppeditor.cpp

@@ -1534,11 +1534,6 @@ TextEditor::CompletionAssistProvider *CPPEditor::completionAssistProvider()
 
 void CPPEditorWidget::applyFontSettings()
 {
-    TextEditor::BaseTextEditorWidget::applyFontSettings();
-    TextEditor::SyntaxHighlighter *highlighter = baseTextDocument()->syntaxHighlighter();
-    if (!highlighter)
-        return;
-
     const TextEditor::FontSettings &fs = baseTextDocument()->fontSettings();
 
     m_semanticHighlightFormatMap[CppHighlightingSupport::TypeUse] =
@@ -1562,16 +1557,8 @@ void CPPEditorWidget::applyFontSettings()
     m_semanticHighlightFormatMap[CppHighlightingSupport::StringUse] =
             fs.toTextCharFormat(TextEditor::C_STRING);
 
-    // Clear all additional formats since they may have changed
-    QTextBlock b = document()->firstBlock();
-    while (b.isValid()) {
-        QList<QTextLayout::FormatRange> noFormats;
-        highlighter->setExtraAdditionalFormats(b, noFormats);
-        b = b.next();
-    }
-
-    // This also triggers an update of the additional formats
-    highlighter->rehighlight();
+    // this also makes the document apply font settings
+    TextEditor::BaseTextEditorWidget::applyFontSettings();
 }
 
 void CPPEditorWidget::unCommentSelection()
@@ -2016,6 +2003,20 @@ CPPEditorDocument::CPPEditorDocument()
             this, SLOT(invalidateFormatterCache()));
 }
 
+void CPPEditorDocument::applyFontSettings()
+{
+    if (TextEditor::SyntaxHighlighter *highlighter = syntaxHighlighter()) {
+        // Clear all additional formats since they may have changed
+        QTextBlock b = document()->firstBlock();
+        while (b.isValid()) {
+            QList<QTextLayout::FormatRange> noFormats;
+            highlighter->setExtraAdditionalFormats(b, noFormats);
+            b = b.next();
+        }
+    }
+    BaseTextDocument::applyFontSettings(); // rehighlights and updates additional formats
+}
+
 void CPPEditorDocument::invalidateFormatterCache()
 {
     CppTools::QtStyleCodeFormatter formatter;

src/plugins/cppeditor/cppeditor.h

@@ -77,6 +77,9 @@ class CPPEditorDocument : public TextEditor::BaseTextDocument
 public:
     CPPEditorDocument();
 
+protected:
+    void applyFontSettings();
+
 private slots:
     void invalidateFormatterCache();
 };

src/plugins/pythoneditor/pythoneditorwidget.cpp

@@ -85,20 +85,6 @@ void EditorWidget::unCommentSelection()
     Utils::unCommentSelection(this, m_commentDefinition);
 }
 
-/**
-  Handles common IDE fonts&colors settings
-  (Tools -> Options -> Text editor -> Fonts and colors)
-  */
-void EditorWidget::applyFontSettings()
-{
-    TextEditor::BaseTextEditorWidget::applyFontSettings();
-
-    PythonHighlighter *highlighter =
-            qobject_cast<PythonHighlighter *>(baseTextDocument()->syntaxHighlighter());
-    if (highlighter)
-        highlighter->setFontSettings(baseTextDocument()->fontSettings());
-}
-
 TextEditor::BaseTextEditor *EditorWidget::createEditor()
 {
     return new PythonEditor(this);

src/plugins/pythoneditor/pythoneditorwidget.h

@@ -48,7 +48,6 @@ public:
     virtual void unCommentSelection();
 
 protected:
-    void applyFontSettings();
     TextEditor::BaseTextEditor *createEditor();
 
 private:

src/plugins/texteditor/basetextdocument.cpp

@@ -79,6 +79,7 @@ public:
     TabSettings m_tabSettings;
     ExtraEncodingSettings m_extraEncodingSettings;
     FontSettings m_fontSettings;
+    bool m_fontSettingsNeedsApply; // for applying font settings delayed till an editor becomes visible
     QTextDocument *m_document;
     SyntaxHighlighter *m_highlighter;
     QScopedPointer<Indenter> m_indenter;
@@ -88,6 +89,7 @@ public:
 };
 
 BaseTextDocumentPrivate::BaseTextDocumentPrivate(BaseTextDocument *q) :
+    m_fontSettingsNeedsApply(false),
     m_document(new QTextDocument(q)),
     m_highlighter(0),
     m_indenter(new Indenter),
@@ -237,9 +239,26 @@ void BaseTextDocument::setFontSettings(const FontSettings &fontSettings)
     if (fontSettings == d->m_fontSettings)
         return;
     d->m_fontSettings = fontSettings;
+    d->m_fontSettingsNeedsApply = true;
     emit fontSettingsChanged();
 }
 
+void BaseTextDocument::ensureFontSettingsApplied()
+{
+    if (!d->m_fontSettingsNeedsApply)
+        return;
+    d->m_fontSettingsNeedsApply = false;
+    applyFontSettings();
+}
+
+void BaseTextDocument::applyFontSettings()
+{
+    if (d->m_highlighter) {
+        d->m_highlighter->setFontSettings(d->m_fontSettings);
+        d->m_highlighter->rehighlight();
+    }
+}
+
 const FontSettings &BaseTextDocument::fontSettings() const
 {
     return d->m_fontSettings;

src/plugins/texteditor/basetextdocument.h

@@ -112,6 +112,8 @@ public:
     bool reload(QString *errorString, QTextCodec *codec);
     void cleanWhitespace(const QTextCursor &cursor);
 
+    void ensureFontSettingsApplied();
+
 public slots:
     void setTabSettings(const TextEditor::TabSettings &tabSettings);
     void setFontSettings(const TextEditor::FontSettings &fontSettings);
@@ -121,6 +123,9 @@ signals:
     void tabSettingsChanged();
     void fontSettingsChanged();
 
+protected slots:
+    virtual void applyFontSettings();
+
 private:
     void cleanWhitespace(QTextCursor &cursor, bool cleanIndentation, bool inEntireDocument);
     void ensureFinalNewLine(QTextCursor &cursor);

src/plugins/texteditor/basetexteditor.cpp

@@ -5429,11 +5429,7 @@ void BaseTextEditorWidget::applyFontSettings()
     slotUpdateExtraAreaWidth();   // Adjust to new font width
     updateCurrentLineHighlight(); // Make sure it takes the new color
 
-    SyntaxHighlighter *highlighter = baseTextDocument()->syntaxHighlighter();
-    if (highlighter) {
-        highlighter->setFontSettings(fs);
-        highlighter->rehighlight();
-    }
+    baseTextDocument()->ensureFontSettingsApplied();
 }
 
 void BaseTextEditorWidget::setDisplaySettings(const DisplaySettings &ds)