Refactor HighlightScrollBar

Rename it into HighlightScrollBarController.
Don't derive it anymore from QScrollBar.
Make it based on QObject and decorate
the existing instance of QAbstractScrollArea as needed.

Fix the highlight of the shared scrollbar of the SideBySideDiffEditor.
Both left and right diff editors have their own
HighlightScrollBarController and their own separate overlays, but both
overlays are created as children of the same right editor instance.

Synchronize also the cursor between left and right editors.
Make highlight current line working.

Make the overlay transparent for mouse events - this fixes
issues on macOS when scolling over invisible scrollbar.

Change-Id: Iab05c360173e09d8748658c59785da86438a7189
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/coreplugin/coreplugin.qbs

@@ -223,8 +223,8 @@ Project {
                 "findtoolwindow.cpp",
                 "findtoolwindow.h",
                 "findwidget.ui",
-                "highlightscrollbar.cpp",
+                "highlightscrollbarcontroller.cpp",
-                "highlightscrollbar.h",
+                "highlightscrollbarcontroller.h",
                 "ifindfilter.cpp",
                 "ifindfilter.h",
                 "ifindsupport.cpp",

src/plugins/coreplugin/find/find.pri

@@ -4,6 +4,7 @@ HEADERS += \
     $$PWD/findplugin.h \
     $$PWD/findtoolbar.h \
     $$PWD/findtoolwindow.h \
+    $$PWD/highlightscrollbarcontroller.h \
     $$PWD/ifindfilter.h \
     $$PWD/ifindsupport.h \
     $$PWD/itemviewfind.h \
@@ -16,7 +17,6 @@ HEADERS += \
     $$PWD/searchresultwidget.h \
     $$PWD/searchresultwindow.h \
     $$PWD/textfindconstants.h \
-    $$PWD/highlightscrollbar.h \
     $$PWD/searchresultitem.h
 
 SOURCES += \
@@ -25,6 +25,7 @@ SOURCES += \
     $$PWD/findplugin.cpp \
     $$PWD/findtoolbar.cpp \
     $$PWD/findtoolwindow.cpp \
+    $$PWD/highlightscrollbarcontroller.cpp \
     $$PWD/ifindfilter.cpp \
     $$PWD/ifindsupport.cpp \
     $$PWD/itemviewfind.cpp \
@@ -33,8 +34,7 @@ SOURCES += \
     $$PWD/searchresulttreemodel.cpp \
     $$PWD/searchresulttreeview.cpp \
     $$PWD/searchresultwidget.cpp \
-    $$PWD/searchresultwindow.cpp \
+    $$PWD/searchresultwindow.cpp
-    $$PWD/highlightscrollbar.cpp
 
 
 FORMS += \

src/plugins/coreplugin/find/highlightscrollbarcontroller.cpp

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of Qt Creator.
@@ -23,13 +23,14 @@
 **
 ****************************************************************************/
 
-#include "highlightscrollbar.h"
+#include "highlightscrollbarcontroller.h"
 
 #include <utils/asconst.h>
-#include <utils/qtcassert.h>
 
+#include <QAbstractScrollArea>
 #include <QPainter>
 #include <QResizeEvent>
+#include <QScrollBar>
 #include <QStyle>
 #include <QStyleOptionSlider>
 #include <QTimer>
@@ -40,164 +41,45 @@ namespace Core {
 class HighlightScrollBarOverlay : public QWidget
 {
 public:
-    HighlightScrollBarOverlay(HighlightScrollBar *scrollBar)
+    HighlightScrollBarOverlay(HighlightScrollBarController *scrollBarController)
-        : QWidget(scrollBar)
+        : QWidget(scrollBarController->scrollArea())
-        , m_visibleRange(0.0)
+        , m_scrollBar(scrollBarController->scrollBar())
-        , m_offset(0.0)
+        , m_highlightController(scrollBarController)
-        , m_cacheUpdateScheduled(false)
+    {
-        , m_scrollBar(scrollBar)
+        setAttribute(Qt::WA_TransparentForMouseEvents);
-    {}
+        m_scrollBar->parentWidget()->installEventFilter(this);
+        doResize();
+        doMove();
+        show();
+    }
+
+    void doResize()
+    {
+        resize(m_scrollBar->size());
+    }
+
+    void doMove()
+    {
+        move(parentWidget()->mapFromGlobal(m_scrollBar->mapToGlobal(m_scrollBar->pos())));
+    }
 
     void scheduleUpdate();
-    void updateCache();
-    void adjustPosition();
-
-    float m_visibleRange;
-    float m_offset;
-    QHash<Id, QVector<Highlight> > m_highlights;
-
-    bool m_cacheUpdateScheduled;
-    QMap<int, Highlight> m_cache;
 
 protected:
     void paintEvent(QPaintEvent *paintEvent) override;
+    bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
-    HighlightScrollBar *m_scrollBar;
+    void updateCache();
+    QRect overlayRect() const;
+
+    bool m_cacheUpdateScheduled = true;
+    QMap<int, Highlight> m_cache;
+
+    QScrollBar *m_scrollBar;
+    HighlightScrollBarController *m_highlightController;
 };
 
-HighlightScrollBar::HighlightScrollBar(Qt::Orientation orientation, QWidget *parent)
-    : QScrollBar(orientation, parent)
-    , m_widget(parent)
-    , m_overlay(new HighlightScrollBarOverlay(this))
-{
-    connect(m_overlay, &HighlightScrollBarOverlay::destroyed,
-            this, &HighlightScrollBar::overlayDestroyed);
-    // valueChanged(0) flashes transient scroll bars, which is needed
-    // for a correct initialization.
-    emit valueChanged(0);
-}
-
-HighlightScrollBar::~HighlightScrollBar()
-{
-    if (!m_overlay || m_overlay->parent() == this)
-        return;
-
-    delete m_overlay;
-}
-
-void HighlightScrollBar::setVisibleRange(float visibleRange)
-{
-    if (!m_overlay)
-        return;
-    m_overlay->m_visibleRange = visibleRange;
-}
-
-void HighlightScrollBar::setRangeOffset(float offset)
-{
-    if (!m_overlay)
-        return;
-    m_overlay->m_offset = offset;
-}
-
-QRect HighlightScrollBar::overlayRect()
-{
-    QStyleOptionSlider opt;
-    initStyleOption(&opt);
-    return style()->subControlRect(QStyle::CC_ScrollBar, &opt, QStyle::SC_ScrollBarGroove, this);
-}
-
-void HighlightScrollBar::overlayDestroyed()
-{
-    m_overlay = 0;
-}
-
-void HighlightScrollBar::addHighlight(Highlight highlight)
-{
-    if (!m_overlay)
-        return;
-    m_overlay->m_highlights[highlight.category] << highlight;
-    m_overlay->scheduleUpdate();
-}
-
-void HighlightScrollBar::removeHighlights(Id category)
-{
-    if (!m_overlay)
-        return;
-    m_overlay->m_highlights.remove(category);
-    m_overlay->scheduleUpdate();
-}
-
-void HighlightScrollBar::removeAllHighlights()
-{
-    if (!m_overlay)
-        return;
-    m_overlay->m_highlights.clear();
-    m_overlay->scheduleUpdate();
-}
-
-bool HighlightScrollBar::eventFilter(QObject *obj, QEvent *event)
-{
-    if (obj == m_widget && m_overlay && m_widget == m_overlay->parent() &&
-            (event->type() == QEvent::Resize || event->type() == QEvent::Move)) {
-        QStyleOptionSlider opt;
-        initStyleOption(&opt);
-        const int width = style()->pixelMetric(QStyle::PM_ScrollBarExtent, &opt, this);
-        m_overlay->move(m_widget->width() - width, 0);
-        resize(width, m_widget->height());
-    }
-    return false;
-}
-
-void HighlightScrollBar::resizeEvent(QResizeEvent *event)
-{
-    if (!m_overlay)
-        return;
-    QScrollBar::resizeEvent(event);
-    m_overlay->resize(size());
-}
-
-void HighlightScrollBar::moveEvent(QMoveEvent *event)
-{
-    if (!m_overlay)
-        return;
-    QScrollBar::moveEvent(event);
-    m_overlay->adjustPosition();
-}
-
-void HighlightScrollBar::showEvent(QShowEvent *event)
-{
-    if (!m_overlay)
-        return;
-    QScrollBar::showEvent(event);
-    if (parentWidget() != this) {
-        m_widget->removeEventFilter(this);
-        m_overlay->setParent(this);
-        m_overlay->adjustPosition();
-        m_overlay->show();
-    }
-}
-
-void HighlightScrollBar::hideEvent(QHideEvent *event)
-{
-    if (!m_overlay)
-        return;
-    QScrollBar::hideEvent(event);
-    if (parentWidget() != m_widget) {
-        m_widget->installEventFilter(this);
-        m_overlay->setParent(m_widget);
-        m_overlay->adjustPosition();
-        m_overlay->show();
-    }
-}
-
-void HighlightScrollBar::changeEvent(QEvent *event)
-{
-    // Workaround for QTBUG-45579
-    if (event->type() == QEvent::ParentChange)
-        setStyle(style());
-}
-
 void HighlightScrollBarOverlay::scheduleUpdate()
 {
     if (m_cacheUpdateScheduled)
@@ -207,28 +89,6 @@ void HighlightScrollBarOverlay::scheduleUpdate()
     QTimer::singleShot(0, this, static_cast<void (QWidget::*)()>(&QWidget::update));
 }
 
-void HighlightScrollBarOverlay::updateCache()
-{
-    if (!m_cacheUpdateScheduled)
-        return;
-
-    m_cache.clear();
-    const QList<Id> &categories = m_highlights.keys();
-    for (const Id &category : categories) {
-        for (const Highlight &highlight : Utils::asConst(m_highlights[category])) {
-            Highlight oldHighlight = m_cache[highlight.position];
-            if (highlight.priority > oldHighlight.priority)
-                m_cache[highlight.position] = highlight;
-        }
-    }
-    m_cacheUpdateScheduled = false;
-}
-
-void HighlightScrollBarOverlay::adjustPosition()
-{
-    move(parentWidget()->mapFromGlobal(m_scrollBar->mapToGlobal(m_scrollBar->pos())));
-}
-
 void HighlightScrollBarOverlay::paintEvent(QPaintEvent *paintEvent)
 {
     QWidget::paintEvent(paintEvent);
@@ -238,23 +98,23 @@ void HighlightScrollBarOverlay::paintEvent(QPaintEvent *paintEvent)
     if (m_cache.isEmpty())
         return;
 
-    const QRect &rect = m_scrollBar->overlayRect();
+    const QRect &rect = overlayRect();
 
     Utils::Theme::Color previousColor = Utils::Theme::TextColorNormal;
     Highlight::Priority previousPriority = Highlight::LowPriority;
-    QRect *previousRect = 0;
+    QRect *previousRect = nullptr;
 
     const int scrollbarRange = m_scrollBar->maximum() + m_scrollBar->pageStep();
-    const int range = qMax(m_visibleRange, float(scrollbarRange));
+    const int range = qMax(m_highlightController->visibleRange(), float(scrollbarRange));
     const int horizontalMargin = 3;
     const int resultWidth = rect.width() - 2 * horizontalMargin + 1;
     const int resultHeight = qMin(int(rect.height() / range) + 1, 4);
-    const int offset = rect.height() / range * m_offset;
+    const int offset = rect.height() / range * m_highlightController->rangeOffset();
     const int verticalMargin = ((rect.height() / range) - resultHeight) / 2;
     int previousBottom = -1;
 
     QHash<Utils::Theme::Color, QVector<QRect> > highlights;
-    for (Highlight currentHighlight : Utils::asConst(m_cache)) {
+    for (const Highlight &currentHighlight : Utils::asConst(m_cache)) {
         // Calculate top and bottom
         int top = rect.top() + offset + verticalMargin
                 + float(currentHighlight.position) / range * rect.height();
@@ -301,6 +161,50 @@ void HighlightScrollBarOverlay::paintEvent(QPaintEvent *paintEvent)
     }
 }
 
+bool HighlightScrollBarOverlay::eventFilter(QObject *object, QEvent *event)
+{
+    switch (event->type()) {
+    case QEvent::Move:
+        doMove();
+        break;
+    case QEvent::Resize:
+        doResize();
+        break;
+    case QEvent::ZOrderChange:
+        raise();
+        break;
+    default:
+        break;
+    }
+    return QWidget::eventFilter(object, event);
+}
+
+void HighlightScrollBarOverlay::updateCache()
+{
+    if (!m_cacheUpdateScheduled)
+        return;
+
+    m_cache.clear();
+    const QHash<Id, QVector<Highlight>> highlights = m_highlightController->highlights();
+    const QList<Id> &categories = highlights.keys();
+    for (const Id &category : categories) {
+        for (const Highlight &highlight : highlights.value(category)) {
+            const Highlight oldHighlight = m_cache.value(highlight.position);
+            if (highlight.priority > oldHighlight.priority)
+                m_cache[highlight.position] = highlight;
+        }
+    }
+    m_cacheUpdateScheduled = false;
+}
+
+QRect HighlightScrollBarOverlay::overlayRect() const
+{
+    QStyleOptionSlider opt = qt_qscrollbarStyleOption(m_scrollBar);
+    return m_scrollBar->style()->subControlRect(QStyle::CC_ScrollBar, &opt, QStyle::SC_ScrollBarGroove, m_scrollBar);
+}
+
+/////////////
+
 Highlight::Highlight(Id category_, int position_,
                      Theme::Color color_, Highlight::Priority priority_)
     : category(category_)
@@ -310,4 +214,95 @@ Highlight::Highlight(Id category_, int position_,
 {
 }
 
+/////////////
+
+HighlightScrollBarController::~HighlightScrollBarController()
+{
+    if (m_overlay)
+        delete m_overlay;
+}
+
+QScrollBar *HighlightScrollBarController::scrollBar() const
+{
+    if (m_scrollArea)
+        return m_scrollArea->verticalScrollBar();
+
+    return nullptr;
+}
+
+QAbstractScrollArea *HighlightScrollBarController::scrollArea() const
+{
+    return m_scrollArea;
+}
+
+void HighlightScrollBarController::setScrollArea(QAbstractScrollArea *scrollArea)
+{
+    if (m_scrollArea == scrollArea)
+        return;
+
+    if (m_overlay) {
+        delete m_overlay;
+        m_overlay = nullptr;
+    }
+
+    m_scrollArea = scrollArea;
+
+    if (m_scrollArea) {
+        m_overlay = new HighlightScrollBarOverlay(this);
+        m_overlay->scheduleUpdate();
+    }
+}
+
+float HighlightScrollBarController::visibleRange() const
+{
+    return m_visibleRange;
+}
+
+void HighlightScrollBarController::setVisibleRange(float visibleRange)
+{
+    m_visibleRange = visibleRange;
+}
+
+float HighlightScrollBarController::rangeOffset() const
+{
+    return m_rangeOffset;
+}
+
+void HighlightScrollBarController::setRangeOffset(float offset)
+{
+    m_rangeOffset = offset;
+}
+
+QHash<Id, QVector<Highlight>> HighlightScrollBarController::highlights() const
+{
+    return m_highlights;
+}
+
+void HighlightScrollBarController::addHighlight(Highlight highlight)
+{
+    if (!m_overlay)
+        return;
+
+    m_highlights[highlight.category] << highlight;
+    m_overlay->scheduleUpdate();
+}
+
+void HighlightScrollBarController::removeHighlights(Id category)
+{
+    if (!m_overlay)
+        return;
+
+    m_highlights.remove(category);
+    m_overlay->scheduleUpdate();
+}
+
+void HighlightScrollBarController::removeAllHighlights()
+{
+    if (!m_overlay)
+        return;
+
+    m_highlights.clear();
+    m_overlay->scheduleUpdate();
+}
+
 } // namespace Core

src/plugins/coreplugin/find/highlightscrollbarcontroller.h

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of Qt Creator.
@@ -25,14 +25,19 @@
 
 #pragma once
 
-#include <QMap>
+#include <QHash>
-#include <QScrollBar>
+#include <QPointer>
-#include <QSet>
+#include <QVector>
 
 #include <coreplugin/core_global.h>
 #include <coreplugin/id.h>
 #include <utils/theme/theme.h>
 
+QT_BEGIN_NAMESPACE
+class QAbstractScrollArea;
+class QScrollBar;
+QT_END_NAMESPACE
+
 namespace Core {
 
 struct CORE_EXPORT Highlight
@@ -56,38 +61,34 @@ struct CORE_EXPORT Highlight
 
 class HighlightScrollBarOverlay;
 
-class CORE_EXPORT HighlightScrollBar : public QScrollBar
+class CORE_EXPORT HighlightScrollBarController
 {
-    Q_OBJECT
-
 public:
-    HighlightScrollBar(Qt::Orientation orientation, QWidget *parent = 0);
+    HighlightScrollBarController() = default;
-    ~HighlightScrollBar() override;
+    ~HighlightScrollBarController();
 
+    QScrollBar *scrollBar() const;
+    QAbstractScrollArea *scrollArea() const;
+    void setScrollArea(QAbstractScrollArea *scrollArea);
+
+    float visibleRange() const;
     void setVisibleRange(float visibleRange);
+
+    float rangeOffset() const;
     void setRangeOffset(float offset);
 
+    QHash<Id, QVector<Highlight>> highlights() const;
     void addHighlight(Highlight highlight);
 
     void removeHighlights(Id id);
     void removeAllHighlights();
 
-    bool eventFilter(QObject *, QEvent *event) override;
-
-protected:
-    void moveEvent(QMoveEvent *event) override;
-    void resizeEvent(QResizeEvent *event) override;
-    void showEvent(QShowEvent *event) override;
-    void hideEvent(QHideEvent *event) override;
-    void changeEvent(QEvent *even) override;
-
 private:
-    QRect overlayRect();
+    QHash<Id, QVector<Highlight> > m_highlights;
-    void overlayDestroyed();
+    float m_visibleRange = 0.0;
-
+    float m_rangeOffset = 0.0;
-    QWidget *m_widget;
+    QAbstractScrollArea *m_scrollArea = nullptr;
-    HighlightScrollBarOverlay *m_overlay;
+    QPointer<HighlightScrollBarOverlay> m_overlay;
-    friend class HighlightScrollBarOverlay;
 };
 
 } // namespace Core

src/plugins/diffeditor/diffeditor.cpp

@@ -108,7 +108,6 @@ DescriptionEditorWidget::DescriptionEditorWidget(QWidget *parent)
     DisplaySettings settings = displaySettings();
     settings.m_textWrapping = false;
     settings.m_displayLineNumbers = false;
-    settings.m_highlightCurrentLine = false;
     settings.m_displayFoldingMarkers = false;
     settings.m_markTextChanges = false;
     settings.m_highlightBlocks = false;
@@ -143,6 +142,8 @@ void DescriptionEditorWidget::setDisplaySettings(const DisplaySettings &ds)
 {
     DisplaySettings settings = displaySettings();
     settings.m_visualizeWhitespace = ds.m_visualizeWhitespace;
+    settings.m_scrollBarHighlights = ds.m_scrollBarHighlights;
+    settings.m_highlightCurrentLine = ds.m_highlightCurrentLine;
     TextEditorWidget::setDisplaySettings(settings);
 }
 

src/plugins/diffeditor/sidebysidediffeditorwidget.cpp

@@ -42,6 +42,7 @@
 #include <texteditor/displaysettings.h>
 
 #include <coreplugin/icore.h>
+#include <coreplugin/find/highlightscrollbarcontroller.h>
 #include <coreplugin/minisplitter.h>
 
 #include <utils/tooltip/tooltip.h>
@@ -98,6 +99,8 @@ signals:
                               int diffFileIndex,
                               int chunkIndex);
     void foldChanged(int blockNumber, bool folded);
+    void gotDisplaySettings();
+    void gotFocus();
 
 protected:
     int extraAreaWidth(int *markWidthPtr = nullptr) const override {
@@ -124,6 +127,7 @@ protected:
                                  const QTextBlock &block,
                                  QPointF offset,
                                  const QRect &clip) override;
+    void focusInEvent(QFocusEvent *e) override;
 
 private:
     void paintSeparator(QPainter &painter, QColor &color, const QString &text,
@@ -158,7 +162,6 @@ SideDiffEditorWidget::SideDiffEditorWidget(QWidget *parent)
     DisplaySettings settings = displaySettings();
     settings.m_textWrapping = false;
     settings.m_displayLineNumbers = true;
-    settings.m_highlightCurrentLine = false;
     settings.m_markTextChanges = false;
     settings.m_highlightBlocks = false;
     SelectableTextEditorWidget::setDisplaySettings(settings);
@@ -217,7 +220,10 @@ void SideDiffEditorWidget::setDisplaySettings(const DisplaySettings &ds)
     DisplaySettings settings = displaySettings();
     settings.m_visualizeWhitespace = ds.m_visualizeWhitespace;
     settings.m_displayFoldingMarkers = ds.m_displayFoldingMarkers;
+    settings.m_scrollBarHighlights = ds.m_scrollBarHighlights;
+    settings.m_highlightCurrentLine = ds.m_highlightCurrentLine;
     SelectableTextEditorWidget::setDisplaySettings(settings);
+    emit gotDisplaySettings();
 }
 
 void SideDiffEditorWidget::applyFontSettings()
@@ -604,6 +610,12 @@ void SideDiffEditorWidget::drawCollapsedBlockPopup(QPainter &painter,
     m_drawCollapsedClip = clip;
 }
 
+void SideDiffEditorWidget::focusInEvent(QFocusEvent *e)
+{
+    SelectableTextEditorWidget::focusInEvent(e);
+    emit gotFocus();
+}
+
 //////////////////
 
 SideBySideDiffEditorWidget::SideBySideDiffEditorWidget(QWidget *parent)
@@ -613,9 +625,6 @@ SideBySideDiffEditorWidget::SideBySideDiffEditorWidget(QWidget *parent)
     m_leftEditor = new SideDiffEditorWidget(this);
     m_leftEditor->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     m_leftEditor->setReadOnly(true);
-    connect(TextEditorSettings::instance(), &TextEditorSettings::displaySettingsChanged,
-            m_leftEditor, &SideDiffEditorWidget::setDisplaySettings);
-    m_leftEditor->setDisplaySettings(TextEditorSettings::displaySettings());
     m_leftEditor->setCodeStyle(TextEditorSettings::codeStyle());
     connect(m_leftEditor, &SideDiffEditorWidget::jumpToOriginalFileRequested,
             this, &SideBySideDiffEditorWidget::slotLeftJumpToOriginalFileRequested);
@@ -625,9 +634,6 @@ SideBySideDiffEditorWidget::SideBySideDiffEditorWidget(QWidget *parent)
 
     m_rightEditor = new SideDiffEditorWidget(this);
     m_rightEditor->setReadOnly(true);
-    connect(TextEditorSettings::instance(), &TextEditorSettings::displaySettingsChanged,
-            m_rightEditor, &SideDiffEditorWidget::setDisplaySettings);
-    m_rightEditor->setDisplaySettings(TextEditorSettings::displaySettings());
     m_rightEditor->setCodeStyle(TextEditorSettings::codeStyle());
     connect(m_rightEditor, &SideDiffEditorWidget::jumpToOriginalFileRequested,
             this, &SideBySideDiffEditorWidget::slotRightJumpToOriginalFileRequested);
@@ -635,6 +641,44 @@ SideBySideDiffEditorWidget::SideBySideDiffEditorWidget(QWidget *parent)
             this, &SideBySideDiffEditorWidget::slotRightContextMenuRequested,
             Qt::DirectConnection);
 
+    auto setupHighlightController = [this]() {
+        HighlightScrollBarController *highlightController = m_leftEditor->highlightScrollBarController();
+        if (highlightController)
+            highlightController->setScrollArea(m_rightEditor);
+    };
+
+    setupHighlightController();
+    connect(m_leftEditor, &SideDiffEditorWidget::gotDisplaySettings, setupHighlightController);
+
+    m_rightEditor->verticalScrollBar()->setFocusProxy(m_leftEditor);
+    connect(m_leftEditor, &SideDiffEditorWidget::gotFocus, [this]() {
+        if (m_rightEditor->verticalScrollBar()->focusProxy() == m_leftEditor)
+            return; // We already did it before.
+
+        // Hack #1. If the left editor got a focus last time
+        // we don't want to focus right editor when clicking the right
+        // scrollbar.
+        m_rightEditor->verticalScrollBar()->setFocusProxy(m_leftEditor);
+
+        // Hack #2. If the focus is currently not on the scrollbar's proxy
+        // and we click on the scrollbar, the focus will go to the parent
+        // of the scrollbar. In order to give the focus to the proxy
+        // we need to set a click focus policy on the scrollbar.
+        // See QApplicationPrivate::giveFocusAccordingToFocusPolicy().
+        m_rightEditor->verticalScrollBar()->setFocusPolicy(Qt::ClickFocus);
+
+        // Hack #3. Setting the focus policy is not orthogonal to setting
+        // the focus proxy and unfortuantely it changes the policy of the proxy
+        // too. We bring back the original policy to keep tab focus working.
+        m_leftEditor->setFocusPolicy(Qt::StrongFocus);
+    });
+    connect(m_rightEditor, &SideDiffEditorWidget::gotFocus, [this]() {
+        // Unhack #1.
+        m_rightEditor->verticalScrollBar()->setFocusProxy(nullptr);
+        // Unhack #2.
+        m_rightEditor->verticalScrollBar()->setFocusPolicy(Qt::NoFocus);
+    });
+
     connect(TextEditorSettings::instance(),
             &TextEditorSettings::fontSettingsChanged,
             this, &SideBySideDiffEditorWidget::setFontSettings);
@@ -678,7 +722,7 @@ SideBySideDiffEditorWidget::SideBySideDiffEditorWidget(QWidget *parent)
     QVBoxLayout *l = new QVBoxLayout(this);
     l->setMargin(0);
     l->addWidget(m_splitter);
-    setFocusProxy(m_rightEditor);
+    setFocusProxy(m_leftEditor);
 
     m_leftContext = new IContext(this);
     m_leftContext->setWidget(m_leftEditor);
@@ -1060,32 +1104,43 @@ void SideBySideDiffEditorWidget::leftCursorPositionChanged()
 {
     leftVSliderChanged();
     leftHSliderChanged();
-
+    handlePositionChange(m_leftEditor, m_rightEditor);
-    if (m_controller.m_ignoreCurrentIndexChange)
-        return;
-
-    const bool oldIgnore = m_controller.m_ignoreCurrentIndexChange;
-    m_controller.m_ignoreCurrentIndexChange = true;
-    emit currentDiffFileIndexChanged(
-                m_leftEditor->fileIndexForBlockNumber(m_leftEditor->textCursor().blockNumber()));
-    m_controller.m_ignoreCurrentIndexChange = oldIgnore;
 }
 
 void SideBySideDiffEditorWidget::rightCursorPositionChanged()
 {
     rightVSliderChanged();
     rightHSliderChanged();
+    handlePositionChange(m_rightEditor, m_leftEditor);
+}
 
+void SideBySideDiffEditorWidget::handlePositionChange(SideDiffEditorWidget *source, SideDiffEditorWidget *dest)
+{
     if (m_controller.m_ignoreCurrentIndexChange)
         return;
 
     const bool oldIgnore = m_controller.m_ignoreCurrentIndexChange;
     m_controller.m_ignoreCurrentIndexChange = true;
+    syncCursor(source, dest);
     emit currentDiffFileIndexChanged(
-                m_rightEditor->fileIndexForBlockNumber(m_rightEditor->textCursor().blockNumber()));
+                source->fileIndexForBlockNumber(source->textCursor().blockNumber()));
     m_controller.m_ignoreCurrentIndexChange = oldIgnore;
 }
 
+void SideBySideDiffEditorWidget::syncCursor(SideDiffEditorWidget *source, SideDiffEditorWidget *dest)
+{
+    const QTextCursor sourceCursor = source->textCursor();
+    const int sourceLine = sourceCursor.blockNumber();
+    const int sourceColumn = sourceCursor.positionInBlock();
+    QTextCursor destCursor = dest->textCursor();
+    const QTextBlock destBlock = dest->document()->findBlockByNumber(sourceLine);
+    const int destColumn = qMin(sourceColumn, destBlock.length());
+    const int destPosition = destBlock.position() + destColumn;
+    destCursor.setPosition(destPosition);
+    dest->setTextCursor(destCursor);
+
+}
+
 } // namespace Internal
 } // namespace DiffEditor
 

src/plugins/diffeditor/sidebysidediffeditorwidget.h

@@ -95,6 +95,8 @@ private:
     void rightHSliderChanged();
     void leftCursorPositionChanged();
     void rightCursorPositionChanged();
+    void handlePositionChange(SideDiffEditorWidget *source, SideDiffEditorWidget *dest);
+    void syncCursor(SideDiffEditorWidget *source, SideDiffEditorWidget *dest);
 
     void showDiff();
 

src/plugins/diffeditor/unifieddiffeditorwidget.cpp

@@ -58,7 +58,6 @@ UnifiedDiffEditorWidget::UnifiedDiffEditorWidget(QWidget *parent)
     DisplaySettings settings = displaySettings();
     settings.m_textWrapping = false;
     settings.m_displayLineNumbers = true;
-    settings.m_highlightCurrentLine = false;
     settings.m_markTextChanges = false;
     settings.m_highlightBlocks = false;
     SelectableTextEditorWidget::setDisplaySettings(settings);
@@ -133,6 +132,8 @@ void UnifiedDiffEditorWidget::setDisplaySettings(const DisplaySettings &ds)
     DisplaySettings settings = displaySettings();
     settings.m_visualizeWhitespace = ds.m_visualizeWhitespace;
     settings.m_displayFoldingMarkers = ds.m_displayFoldingMarkers;
+    settings.m_scrollBarHighlights = ds.m_scrollBarHighlights;
+    settings.m_highlightCurrentLine = ds.m_highlightCurrentLine;
     SelectableTextEditorWidget::setDisplaySettings(settings);
 }
 

src/plugins/texteditor/texteditor.cpp

@@ -72,7 +72,7 @@
 #include <coreplugin/infobar.h>
 #include <coreplugin/manhattanstyle.h>
 #include <coreplugin/find/basetextfind.h>
-#include <coreplugin/find/highlightscrollbar.h>
+#include <coreplugin/find/highlightscrollbarcontroller.h>
 #include <utils/algorithm.h>
 #include <utils/asconst.h>
 #include <utils/textutils.h>
@@ -759,7 +759,7 @@ public:
     QFutureWatcher<FileSearchResultList> *m_searchWatcher = nullptr;
     QVector<SearchResult> m_searchResults;
     QTimer m_scrollBarUpdateTimer;
-    HighlightScrollBar *m_highlightScrollBar = nullptr;
+    HighlightScrollBarController *m_highlightScrollBarController = nullptr;
     bool m_scrollBarUpdateScheduled = false;
 };
 
@@ -814,6 +814,7 @@ TextEditorWidgetPrivate::~TextEditorWidgetPrivate()
                         this, &TextEditorWidgetPrivate::markRemoved);
     q->disconnect(this);
     delete m_toolBar;
+    delete m_highlightScrollBarController;
 }
 
 } // namespace Internal
@@ -904,15 +905,15 @@ void TextEditorWidget::setTextDocument(const QSharedPointer<TextDocument> &doc)
 void TextEditorWidgetPrivate::setupScrollBar()
 {
     if (m_displaySettings.m_scrollBarHighlights) {
-        if (m_highlightScrollBar)
+        if (!m_highlightScrollBarController)
-            return;
+            m_highlightScrollBarController = new HighlightScrollBarController();
-        m_highlightScrollBar = new HighlightScrollBar(Qt::Vertical, q);
+
-        q->setVerticalScrollBar(m_highlightScrollBar);
+        m_highlightScrollBarController->setScrollArea(q);
         highlightSearchResultsInScrollBar();
         scheduleUpdateHighlightScrollBar();
-    } else if (m_highlightScrollBar) {
+    } else if (m_highlightScrollBarController) {
-        q->setVerticalScrollBar(new QScrollBar(Qt::Vertical, q));
+        delete m_highlightScrollBarController;
-        m_highlightScrollBar = 0;
+        m_highlightScrollBarController = nullptr;
     }
 }
 
@@ -5311,14 +5312,14 @@ void TextEditorWidgetPrivate::updateHighlights()
 
 void TextEditorWidgetPrivate::updateCurrentLineInScrollbar()
 {
-    if (m_highlightCurrentLine && m_highlightScrollBar) {
+    if (m_highlightCurrentLine && m_highlightScrollBarController) {
-        m_highlightScrollBar->removeHighlights(Constants::SCROLL_BAR_CURRENT_LINE);
+        m_highlightScrollBarController->removeHighlights(Constants::SCROLL_BAR_CURRENT_LINE);
-        if (m_highlightScrollBar->maximum() > 0) {
+        if (m_highlightScrollBarController->scrollBar()->maximum() > 0) {
             const QTextCursor &tc = q->textCursor();
             if (QTextLayout *layout = tc.block().layout()) {
                 const int pos = q->textCursor().block().firstLineNumber() +
                         layout->lineForTextPosition(tc.positionInBlock()).lineNumber();
-                m_highlightScrollBar->addHighlight({Constants::SCROLL_BAR_CURRENT_LINE, pos,
+                m_highlightScrollBarController->addHighlight({Constants::SCROLL_BAR_CURRENT_LINE, pos,
                                                     Theme::TextEditor_CurrentLine_ScrollBarColor,
                                                     Highlight::HighestPriority});
             }
@@ -6213,7 +6214,7 @@ void TextEditorWidgetPrivate::highlightSearchResultsSlot(const QString &txt, Fin
 
     m_delayedUpdateTimer.start(50);
 
-    if (m_highlightScrollBar)
+    if (m_highlightScrollBarController)
         m_scrollBarUpdateTimer.start(50);
 }
 
@@ -6241,22 +6242,22 @@ void TextEditorWidgetPrivate::searchFinished()
 
 void TextEditorWidgetPrivate::adjustScrollBarRanges()
 {
-    if (!m_highlightScrollBar)
+    if (!m_highlightScrollBarController)
         return;
     const float lineSpacing = QFontMetricsF(q->font()).lineSpacing();
     if (lineSpacing == 0)
         return;
 
     const float offset = q->contentOffset().y();
-    m_highlightScrollBar->setVisibleRange((q->viewport()->rect().height() - offset) / lineSpacing);
+    m_highlightScrollBarController->setVisibleRange((q->viewport()->rect().height() - offset) / lineSpacing);
-    m_highlightScrollBar->setRangeOffset(offset / lineSpacing);
+    m_highlightScrollBarController->setRangeOffset(offset / lineSpacing);
 }
 
 void TextEditorWidgetPrivate::highlightSearchResultsInScrollBar()
 {
-    if (!m_highlightScrollBar)
+    if (!m_highlightScrollBarController)
         return;
-    m_highlightScrollBar->removeHighlights(Constants::SCROLL_BAR_SEARCH_RESULT);
+    m_highlightScrollBarController->removeHighlights(Constants::SCROLL_BAR_SEARCH_RESULT);
     m_searchResults.clear();
 
     if (m_searchWatcher) {
@@ -6318,7 +6319,7 @@ Highlight::Priority textMarkPrioToScrollBarPrio(const TextMark::Priority &prio)
 
 void TextEditorWidgetPrivate::addSearchResultsToScrollBar(QVector<SearchResult> results)
 {
-    if (!m_highlightScrollBar)
+    if (!m_highlightScrollBarController)
         return;
     foreach (SearchResult result, results) {
         const QTextBlock &block = q->document()->findBlock(result.start);
@@ -6326,7 +6327,7 @@ void TextEditorWidgetPrivate::addSearchResultsToScrollBar(QVector<SearchResult>
             const int firstLine = block.layout()->lineForTextPosition(result.start - block.position()).lineNumber();
             const int lastLine = block.layout()->lineForTextPosition(result.start - block.position() + result.length).lineNumber();
             for (int line = firstLine; line <= lastLine; ++line) {
-                m_highlightScrollBar->addHighlight(
+                m_highlightScrollBarController->addHighlight(
                     {Constants::SCROLL_BAR_SEARCH_RESULT, block.firstLineNumber() + line,
                             Theme::TextEditor_SearchResult_ScrollBarColor, Highlight::HighPriority});
             }
@@ -6343,10 +6344,10 @@ Highlight markToHighlight(TextMark *mark, int lineNumber)
 void TextEditorWidgetPrivate::updateHighlightScrollBarNow()
 {
     m_scrollBarUpdateScheduled = false;
-    if (!m_highlightScrollBar)
+    if (!m_highlightScrollBarController)
         return;
 
-    m_highlightScrollBar->removeAllHighlights();
+    m_highlightScrollBarController->removeAllHighlights();
 
     updateCurrentLineInScrollbar();
 
@@ -6359,7 +6360,7 @@ void TextEditorWidgetPrivate::updateHighlightScrollBarNow()
             continue;
         const QTextBlock &block = q->document()->findBlockByNumber(mark->lineNumber() - 1);
         if (block.isVisible())
-            m_highlightScrollBar->addHighlight(markToHighlight(mark, block.firstLineNumber()));
+            m_highlightScrollBarController->addHighlight(markToHighlight(mark, block.firstLineNumber()));
     }
 }
 
@@ -8376,6 +8377,11 @@ int TextEditorWidget::centerVisibleLine() const
     return block.isValid() ? block.blockNumber() : -1;
 }
 
+HighlightScrollBarController *TextEditorWidget::highlightScrollBarController() const
+{
+    return d->m_highlightScrollBarController;
+}
+
 bool TextEditorWidget::isMissingSyntaxDefinition() const
 {
     return d->m_isMissingSyntaxDefinition;

src/plugins/texteditor/texteditor.h

@@ -51,6 +51,10 @@ class QRect;
 class QTextBlock;
 QT_END_NAMESPACE
 
+namespace Core {
+class HighlightScrollBarController;
+}
+
 namespace TextEditor {
 class TextDocument;
 class BaseHoverHandler;
@@ -458,6 +462,8 @@ public:
     /*! Returns the line visible closest to the vertical center of the editor. */
     int centerVisibleLine() const;
 
+    Core::HighlightScrollBarController *highlightScrollBarController() const;
+
 signals:
     void assistFinished(); // Used in tests.
     void readOnlyChanged();