Fix scrolling with high resolution mouse/touchpads

Use helper class to accumulate "common steps" of 120 angle delta.

src/lib/lib.pro

@@ -218,6 +218,7 @@ SOURCES += \
     webtab/searchtoolbar.cpp \
     webtab/tabbedwebview.cpp \
     webtab/webtab.cpp \
+    tools/wheelhelper.cpp \
 
 HEADERS  += \
     3rdparty/fancytabwidget.h \
@@ -399,6 +400,7 @@ HEADERS  += \
     webtab/searchtoolbar.h \
     webtab/tabbedwebview.h \
     webtab/webtab.h \
+    tools/wheelhelper.h \
 
 FORMS    += \
     adblock/adblockaddsubscriptiondialog.ui \

src/lib/tabwidget/combotabbar.cpp

@@ -1,7 +1,7 @@
 /* ============================================================
-* QupZilla - WebKit based browser
+* QupZilla - Qt web browser
 * Copyright (C) 2013-2014 S. Razi Alavizadeh <s.r.alavizadeh@gmail.com>
-* Copyright (C) 2014-2016 David Rosca <nowrep@gmail.com>
+* Copyright (C) 2014-2017 David Rosca <nowrep@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -615,8 +615,24 @@ void ComboTabBar::wheelEvent(QWheelEvent* event)
 {
     event->accept();
 
-    if (qzSettings->alwaysSwitchTabsWithWheel) {
-        setCurrentNextEnabledIndex(event->delta() > 0 ? -1 : 1);
+    if (qzSettings->alwaysSwitchTabsWithWheel || (!m_mainTabBarWidget->isOverflowed() && !m_pinnedTabBarWidget->isOverflowed())) {
+        m_wheelHelper.processEvent(event);
+        while (WheelHelper::Direction direction = m_wheelHelper.takeDirection()) {
+            switch (direction) {
+            case WheelHelper::WheelUp:
+            case WheelHelper::WheelLeft:
+                setCurrentNextEnabledIndex(-1);
+                break;
+
+            case WheelHelper::WheelDown:
+            case WheelHelper::WheelRight:
+                setCurrentNextEnabledIndex(1);
+                break;
+
+            default:
+                break;
+            }
+        }
         return;
     }
 
@@ -636,10 +652,6 @@ void ComboTabBar::wheelEvent(QWheelEvent* event)
             m_mainTabBarWidget->scrollByWheel(event);
         }
     }
-
-    if (!m_mainTabBarWidget->isOverflowed() && !m_pinnedTabBarWidget->isOverflowed()) {
-        setCurrentNextEnabledIndex(event->delta() > 0 ? -1 : 1);
-    }
 }
 
 bool ComboTabBar::eventFilter(QObject* obj, QEvent* ev)

src/lib/tabwidget/combotabbar.h

@@ -1,7 +1,7 @@
 /* ============================================================
-* QupZilla - WebKit based browser
+* QupZilla - Qt web browser
 * Copyright (C) 2013-2014 S. Razi Alavizadeh <s.r.alavizadeh@gmail.com>
-* Copyright (C) 2014-2016 David Rosca <nowrep@gmail.com>
+* Copyright (C) 2014-2017 David Rosca <nowrep@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -20,6 +20,7 @@
 #define COMBOTABBAR_H
 
 #include "qzcommon.h"
+#include "wheelhelper.h"
 
 #include <QTabBar>
 #include <QScrollBar>
@@ -203,6 +204,8 @@ private:
     bool m_usesScrollButtons;
     bool m_blockCurrentChangedSignal;
 
+    WheelHelper m_wheelHelper;
+
     friend class TabBarHelper;
     friend class TabStackedWidget;
 };

src/lib/tools/buttonwithmenu.cpp

@@ -1,6 +1,6 @@
 /* ============================================================
-* QupZilla - WebKit based browser
-* Copyright (C) 2010-2014  David Rosca <nowrep@gmail.com>
+* QupZilla - Qt web browser
+* Copyright (C) 2010-2017 David Rosca <nowrep@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -122,13 +122,23 @@ void ButtonWithMenu::setCurrentIndex(int index, bool emitSignal)
 
 void ButtonWithMenu::wheelEvent(QWheelEvent* event)
 {
-    if (event->delta() > 0) {
+    m_wheelHelper.processEvent(event);
+    while (WheelHelper::Direction direction = m_wheelHelper.takeDirection()) {
+        switch (direction) {
+        case WheelHelper::WheelUp:
+        case WheelHelper::WheelLeft:
             selectPreviousItem();
-    }
-    else {
-        selectNextItem();
-    }
+            break;
 
+        case WheelHelper::WheelDown:
+        case WheelHelper::WheelRight:
+            selectNextItem();
+            break;
+
+        default:
+            break;
+        }
+    }
     event->accept();
 }
 

src/lib/tools/buttonwithmenu.h

@@ -1,6 +1,6 @@
 /* ============================================================
-* QupZilla - WebKit based browser
-* Copyright (C) 2010-2014  David Rosca <nowrep@gmail.com>
+* QupZilla - Qt web browser
+* Copyright (C) 2010-2017 David Rosca <nowrep@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
@@ -21,7 +21,7 @@
 #include <QVariant>
 
 #include "toolbutton.h"
-#include "qzcommon.h"
+#include "wheelhelper.h"
 
 // Only to be used in WebSearchBar
 class ButtonWithMenu : public ToolButton
@@ -88,6 +88,7 @@ private:
     QMenu* m_menu;
     QVector<Item> m_items;
     Item m_currentItem;
+    WheelHelper m_wheelHelper;
 };
 
 // Hint to QVector to use std::realloc on item moving

src/lib/tools/wheelhelper.cpp

@@ -0,0 +1,78 @@
+/* ============================================================
+* QupZilla - Qt web browser
+* Copyright (C) 2017 David Rosca <nowrep@gmail.com>
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+* ============================================================ */
+#include "wheelhelper.h"
+
+#include <QWheelEvent>
+
+WheelHelper::WheelHelper()
+{
+}
+
+void WheelHelper::reset()
+{
+    m_wheelDelta = 0;
+    m_directions.clear();
+}
+
+void WheelHelper::processEvent(QWheelEvent *event)
+{
+    int delta = event->angleDelta().x() ? event->angleDelta().x() : event->angleDelta().y();
+    bool directionY = delta == event->angleDelta().y();
+
+    // When scroll to both directions, prefer the major one
+    if (event->angleDelta().x() && event->angleDelta().y()) {
+        if (std::abs(event->angleDelta().y()) > std::abs(event->angleDelta().x())) {
+            delta = event->angleDelta().y();
+            directionY = true;
+        } else {
+            delta = event->angleDelta().x();
+            directionY = false;
+        }
+    }
+
+    // Reset when direction changes
+    if ((delta < 0 && m_wheelDelta > 0) || (delta > 0 && m_wheelDelta < 0)) {
+        m_wheelDelta = 0;
+    }
+
+    m_wheelDelta += delta;
+
+    // Angle delta 120 for common "one click"
+    // See: http://qt-project.org/doc/qt-5/qml-qtquick-wheelevent.html#angleDelta-prop
+    while (m_wheelDelta >= 120) {
+        m_wheelDelta -= 120;
+        if (directionY) {
+            m_directions.enqueue(WheelUp);
+        } else {
+            m_directions.enqueue(WheelLeft);
+        }
+    }
+    while (m_wheelDelta <= -120) {
+        m_wheelDelta += 120;
+        if (directionY) {
+            m_directions.enqueue(WheelDown);
+        } else {
+            m_directions.enqueue(WheelRight);
+        }
+    }
+}
+
+WheelHelper::Direction WheelHelper::takeDirection()
+{
+    return m_directions.isEmpty() ? None : m_directions.dequeue();
+}

src/lib/tools/wheelhelper.h

@@ -0,0 +1,49 @@
+/* ============================================================
+* QupZilla - Qt web browser
+* Copyright (C) 2017 David Rosca <nowrep@gmail.com>
+*
+* This program is free software: you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation, either version 3 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program.  If not, see <http://www.gnu.org/licenses/>.
+* ============================================================ */
+#ifndef WHEELHELPER_H
+#define WHEELHELPER_H
+
+#include <QQueue>
+
+#include "qzcommon.h"
+
+class QWheelEvent;
+
+class QUPZILLA_EXPORT WheelHelper
+{
+public:
+    enum Direction {
+        None = 0,
+        WheelUp,
+        WheelDown,
+        WheelLeft,
+        WheelRight
+    };
+
+    explicit WheelHelper();
+
+    void reset();
+    void processEvent(QWheelEvent *event);
+    Direction takeDirection();
+
+private:
+    int m_wheelDelta = 0;
+    QQueue<Direction> m_directions;
+};
+
+#endif // WHEELHELPER_H

src/lib/webengine/webview.cpp

@@ -1019,11 +1019,29 @@ void WebView::_wheelEvent(QWheelEvent *event)
     }
 
     if (event->modifiers() & Qt::ControlModifier) {
-        event->delta() > 0 ? zoomIn() : zoomOut();
+        m_wheelHelper.processEvent(event);
+        while (WheelHelper::Direction direction = m_wheelHelper.takeDirection()) {
+            switch (direction) {
+            case WheelHelper::WheelUp:
+            case WheelHelper::WheelLeft:
+                zoomIn();
+                break;
+
+            case WheelHelper::WheelDown:
+            case WheelHelper::WheelRight:
+                zoomOut();
+                break;
+
+            default:
+                break;
+            }
+        }
         event->accept();
         return;
     }
 
+    m_wheelHelper.reset();
+
     // QtWebEngine ignores QApplication::wheelScrollLines() and instead always scrolls 3 lines
     if (event->spontaneous()) {
         const qreal multiplier = QApplication::wheelScrollLines() / 3.0;

src/lib/webengine/webview.h

@@ -23,6 +23,7 @@
 
 #include "qzcommon.h"
 #include "loadrequest.h"
+#include "wheelhelper.h"
 
 class WebPage;
 class LoadRequest;
@@ -189,6 +190,7 @@ private:
     bool m_firstLoad;
 
     QPointer<QWidget> m_rwhvqt;
+    WheelHelper m_wheelHelper;
 
     static bool s_forceContextMenuOnMouseRelease;
 };