SYNERGY-1454 Scroll direction (#7140)

* SYNERGY-1454 Add a new checkbox into the setting dialog

* SYNERGY-1454 Save the new option

* SYNERGY-1454 Pass the new option to client

* SYNERGY-1454 Parse the new param on client side

* SYNERGY-1454 Invert scroll direction for macOS

* SYNERGY-1454 Scroll direction on Windows

* SYNERGY-1454 Remove unused code

* SYNERGY-1454 Scroll direction for Linux

* SYNERGY-1454 Simplify scroll direction for Mac

* SYNERGY-1454 Simplify scroll direction for Linux

* SYNERGY-1454 Simplify scroll direction for Windows

* SYNERGY-1454 ChangeLog

* SYNERGY-1454 Fix code smell

* SYNERGY-1434 Lower case for the first char of the option

* SYNERGY-1454 Fix indentations

Co-authored-by: Serhii Hadzhilov <gadzhilov.sergey@gmail.com>
Co-authored-by: Serhii Hadzhilov <serhii@symless.com>

ChangeLog

@@ -2,6 +2,7 @@ v1.14.3-snapshot
 ===========
 Bug fixes:
 - #7135 Fix issue with function keys on macOS
+- #7140 Configure scroll direction on a per-computer basis
 ===========
 
 v1.14.2-stable

src/gui/src/AppConfig.cpp

@@ -78,7 +78,8 @@ const char* AppConfig::m_SynergySettingsName[] = {
         "tlsCertPath",
         "tlsKeyLength",
         "preventSleep",
-        "languageSync"
+        "languageSync",
+        "invertScrollDirection"
 };
 
 static const char* logLevelNames[] =
@@ -243,6 +244,7 @@ void AppConfig::loadSettings()
     m_ServerHostname            = loadSetting(kServerHostname).toString();
     m_PreventSleep              = loadSetting(kPreventSleep, false).toBool();
     m_LanguageSync              = loadSetting(kLanguageSync, false).toBool();
+    m_InvertScrollDirection     = loadSetting(kInvertScrollDirection, false).toBool();
 
     //only change the serial key if the settings being loaded contains a key
     bool updateSerial = ConfigWriter::make()
@@ -305,6 +307,7 @@ void AppConfig::saveSettings()
         setSetting(kServerHostname, m_ServerHostname);
         setSetting(kPreventSleep, m_PreventSleep);
         setSetting(kLanguageSync, m_LanguageSync);
+        setSetting(kInvertScrollDirection, m_InvertScrollDirection);
     }
 
     m_unsavedChanges = false;
@@ -454,8 +457,16 @@ void AppConfig::setMinimizeToTray(bool newValue) {
     setSettingModified(m_MinimizeToTray, newValue);
 }
 
+bool AppConfig::getInvertScrollDirection() const {
+    return m_InvertScrollDirection;
+}
+
 bool AppConfig::getLanguageSync() const { return m_LanguageSync; }
 
+void AppConfig::setInvertScrollDirection(bool newValue) {
+    setSettingModified(m_InvertScrollDirection, newValue);
+}
+
 void AppConfig::setLanguageSync(bool newValue) {
     setSettingModified(m_LanguageSync, newValue);
 }

src/gui/src/AppConfig.h

@@ -112,6 +112,8 @@ class AppConfig: public QObject, public GUI::Config::ConfigBase
 
         void setAutoHide(bool b);
         bool getAutoHide();
+        void setInvertScrollDirection(bool b);
+        bool getInvertScrollDirection() const;
         void setLanguageSync(bool b);
         bool getLanguageSync() const;
         void setPreventSleep(bool b);
@@ -205,7 +207,8 @@ protected:
         kTLSCertPath,
         kTLSKeyLength,
         kPreventSleep,
-        kLanguageSync
+        kLanguageSync,
+        kInvertScrollDirection
     };
 
         void setScreenName(const QString& s);
@@ -248,6 +251,7 @@ protected:
         int m_LastExpiringWarningTime;
         bool m_ActivationHasRun;
         bool m_MinimizeToTray;
+        bool m_InvertScrollDirection  = false;
         bool m_LanguageSync           = true;
         bool m_PreventSleep           = false;
 

src/gui/src/MainWindow.cpp

@@ -811,6 +811,9 @@ bool MainWindow::clientArgs(QStringList& args, QString& app)
         args << "--sync-language";
     }
 
+    if (appConfig().getInvertScrollDirection()) {
+        args <<"--invert-scroll";
+    }
 
 #if !defined(SYNERGY_ENTERPRISE) && defined(SYNERGY_AUTOCONFIG)
     // check auto config first, if it is disabled or no server detected,

src/gui/src/SettingsDialog.cpp

@@ -53,6 +53,7 @@ SettingsDialog::SettingsDialog(QWidget* parent, AppConfig& config) :
     enableControls(appConfig().isWritable());
 
     m_pCheckBoxLanguageSync->setVisible(m_pMainWindow->synergyType() == MainWindow::synergyClient);
+    m_pCheckBoxScrollDirection->setVisible(m_pMainWindow->synergyType() == MainWindow::synergyClient);
 
     const auto& serveConfig = m_pMainWindow->serverConfig();
     m_pLineEditScreenName->setValidator(new validators::ScreenNameValidator(m_pLineEditScreenName, m_pLabelNameError, (&serveConfig.screens())));
@@ -69,6 +70,7 @@ SettingsDialog::SettingsDialog(QWidget* parent, AppConfig& config) :
     connect(m_pLineEditScreenName,      SIGNAL(textEdited(QString)),      this, SLOT(onChange()));
     connect(m_pComboElevate,            SIGNAL(currentIndexChanged(int)), this, SLOT(onChange()));
     connect(m_pCheckBoxLanguageSync,    SIGNAL(clicked()),                this, SLOT(onChange()));
+    connect(m_pCheckBoxScrollDirection, SIGNAL(clicked()),                this, SLOT(onChange()));
 
     adjustSize();
 }
@@ -92,6 +94,7 @@ void SettingsDialog::accept()
    appConfig().setTLSKeyLength(m_pComboBoxKeyLength->currentText());
    appConfig().setCryptoEnabled(m_pCheckBoxEnableCrypto->isChecked());
    appConfig().setLanguageSync(m_pCheckBoxLanguageSync->isChecked());
+   appConfig().setInvertScrollDirection(m_pCheckBoxScrollDirection->isChecked());
 
    appConfig().saveSettings();
    QDialog::accept();
@@ -150,6 +153,7 @@ void SettingsDialog::loadFromConfig() {
     m_pLineEditCertificatePath->setText(appConfig().getTLSCertPath());
     m_pCheckBoxEnableCrypto->setChecked(m_appConfig.getCryptoEnabled());
     m_pCheckBoxLanguageSync->setChecked(m_appConfig.getLanguageSync());
+    m_pCheckBoxScrollDirection->setChecked(m_appConfig.getInvertScrollDirection());
 
     //If the tls file exists test its key length
     if (QFile(appConfig().getTLSCertPath()).exists()) {
@@ -341,7 +345,8 @@ bool SettingsDialog::isModified()
       || appConfig().getTLSKeyLength()   != m_pComboBoxKeyLength->currentText()
       || appConfig().getCryptoEnabled()  != m_pCheckBoxEnableCrypto->isChecked()
       || appConfig().isSystemScoped()    != m_isSystemAtStart
-      || appConfig().getLanguageSync()   != m_pCheckBoxLanguageSync->isChecked())
+      || appConfig().getLanguageSync()   != m_pCheckBoxLanguageSync->isChecked()
+      || appConfig().getInvertScrollDirection() != m_pCheckBoxScrollDirection->isChecked())
    );
 }
 
@@ -363,6 +368,7 @@ void SettingsDialog::enableControls(bool enable) {
     m_pCheckBoxEnableCrypto->setEnabled(enable);
     m_labelAdminRightsMessage->setVisible(!enable);
     m_pCheckBoxLanguageSync->setEnabled(enable);
+    m_pCheckBoxScrollDirection->setEnabled(enable);
 
     if (enable) {
         m_pLabelLogPath->setEnabled(m_pCheckBoxLogToFile->isChecked());

src/gui/src/SettingsDialogBase.ui

@@ -337,10 +337,33 @@ background-color: rgba(192,192,192, 0.1);
       <enum>QFrame::Raised</enum>
      </property>
      <layout class="QGridLayout" name="gridLayout_3">
-      <item row="0" column="1">
+      <item row="4" column="0">
-       <widget class="QComboBox" name="m_pComboLanguage"/>
+       <widget class="QLabel" name="m_pLabelElevate">
+        <property name="sizePolicy">
+         <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
+          <horstretch>0</horstretch>
+          <verstretch>0</verstretch>
+         </sizepolicy>
+        </property>
+        <property name="text">
+         <string>Elevate privileges</string>
+        </property>
+       </widget>
       </item>
-      <item row="1" column="0" colspan="3">
+      <item row="5" column="0">
+       <spacer name="verticalSpacer_6">
+        <property name="orientation">
+         <enum>Qt::Vertical</enum>
+        </property>
+        <property name="sizeHint" stdset="0">
+         <size>
+          <width>20</width>
+          <height>40</height>
+         </size>
+        </property>
+       </spacer>
+      </item>
+      <item row="2" column="0" colspan="3">
        <widget class="QCheckBox" name="m_pCheckBoxLanguageSync">
         <property name="text">
          <string>&amp;Use server's keyboard language on this machine</string>
@@ -369,20 +392,7 @@ background-color: rgba(192,192,192, 0.1);
         </property>
        </widget>
       </item>
-      <item row="3" column="0">
+      <item row="4" column="1">
-       <widget class="QLabel" name="m_pLabelElevate">
-        <property name="sizePolicy">
-         <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
-          <horstretch>0</horstretch>
-          <verstretch>0</verstretch>
-         </sizepolicy>
-        </property>
-        <property name="text">
-         <string>Elevate privileges</string>
-        </property>
-       </widget>
-      </item>
-      <item row="3" column="1">
        <widget class="QComboBox" name="m_pComboElevate">
         <property name="toolTip">
          <string>Specify when the Synergy service should run at an elevated privilege level</string>
@@ -407,18 +417,15 @@ background-color: rgba(192,192,192, 0.1);
         </item>
        </widget>
       </item>
-      <item row="4" column="0">
+      <item row="0" column="1">
-       <spacer name="verticalSpacer_6">
+       <widget class="QComboBox" name="m_pComboLanguage"/>
-        <property name="orientation">
+      </item>
-         <enum>Qt::Vertical</enum>
+      <item row="1" column="0" colspan="3">
+       <widget class="QCheckBox" name="m_pCheckBoxScrollDirection">
+        <property name="text">
+         <string>Invert scroll direction on this computer</string>
         </property>
-        <property name="sizeHint" stdset="0">
+       </widget>
-         <size>
-          <width>20</width>
-          <height>40</height>
-         </size>
-        </property>
-       </spacer>
       </item>
      </layout>
     </widget>
@@ -1008,7 +1015,6 @@ font-weight: bold;</string>
  </tabstops>
  <resources>
   <include location="../res/Synergy.qrc"/>
-  <include location="../res/Synergy.qrc"/>
  </resources>
  <connections>
   <connection>

src/lib/arch/unix/ArchSystemUnix.cpp

@@ -19,10 +19,6 @@
 #include "arch/unix/ArchSystemUnix.h"
 
 #include <sys/utsname.h>
-#include <stdio.h>
-#include <array>
-#include <memory>
-#include <string>
 #ifndef __APPLE__
 #include <QtDBus>
 #endif
@@ -86,24 +82,6 @@ ArchSystemUnix::getLibsUsed(void) const
     return "not implemented.\nuse lsof on shell";
 }
 
-std::string
-ArchSystemUnix::runCommand(const std::string& cmd)
-{
-    std::array<char, 128> buffer;
-    std::string result;
-    std::unique_ptr<FILE, decltype(&pclose)> pipe(popen(cmd.c_str(), "r"), &pclose);
-    if (!pipe)
-    {
-        return "";
-    }
-
-    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr)
-    {
-        result += buffer.data();
-    }
-    return result;
-}
-
 #ifndef __APPLE__
 bool
 ArchSystemUnix::DBusInhibitScreenCall(InhibitScreenServices serviceID, bool state, std::string& error)

src/lib/arch/unix/ArchSystemUnix.h

@@ -35,8 +35,6 @@ public:
     virtual void setting(const std::string&, const std::string&) const;
     virtual std::string getLibsUsed(void) const;
 
-    static std::string  runCommand(const std::string& cmd);
-
 #ifndef __APPLE__
     enum class InhibitScreenServices {
         kScreenSaver,

src/lib/platform/MSWindowsScreen.cpp

@@ -46,7 +46,6 @@
 #include <Shlobj.h>
 #include <comutil.h>
 #include <algorithm>
-#include <thread>
 
 // suppress warning about GetVersionEx, which is used indirectly in this compilation unit.
 #pragma warning(disable: 4996)
@@ -341,11 +340,6 @@ MSWindowsScreen::leave()
     // tell desk that we're leaving and tell it the keyboard layout
     m_desks->leave(m_keyLayout);
 
-    // Forcefully update scrolling direction
-    // Will keep server updated when moving cursor
-    allowScrollDirectionUpdate();
-    updateScrollDirection();
-
     if (m_isPrimary) {
 
         // warp to center
@@ -831,8 +825,8 @@ MSWindowsScreen::fakeMouseRelativeMove(SInt32 dx, SInt32 dy) const
 void
 MSWindowsScreen::fakeMouseWheel(SInt32 xDelta, SInt32 yDelta) const
 {
-    xDelta = mapScrollFromSynergy(xDelta);
+    xDelta *= ClientApp::instance().args().m_clientScrollDirection;
-    yDelta = mapScrollFromSynergy(yDelta);
+    yDelta *= ClientApp::instance().args().m_clientScrollDirection;
     m_desks->fakeMouseWheel(xDelta, yDelta);
 }
 
@@ -1485,8 +1479,6 @@ MSWindowsScreen::onMouseWheel(SInt32 xDelta, SInt32 yDelta)
     // ignore message if posted prior to last mark change
     if (!ignore()) {
         LOG((CLOG_DEBUG1 "event: button wheel delta=%+d,%+d", xDelta, yDelta));
-        xDelta = mapScrollToSynergy(xDelta);
-        yDelta = mapScrollToSynergy(yDelta);
         sendEvent(m_events->forIPrimaryScreen().wheel(), WheelInfo::alloc(xDelta, yDelta));
     }
     return true;
@@ -2036,56 +2028,3 @@ MSWindowsScreen::isModifierRepeat(KeyModifierMask oldState, KeyModifierMask stat
 
     return result;
 }
-
-SInt32
-MSWindowsScreen::mapScrollToSynergy(SInt32 delta) const
-{
-    // for mouse wheel the delta will be a multiple of WHEEL_DELTA
-    if (delta % WHEEL_DELTA == 0)
-    {
-        return delta * m_scrollDirectionMouse;
-    }
-    else
-    {
-        return delta * m_scrollDirectionTouchpad;
-    }
-}
-
-SInt32
-MSWindowsScreen::mapScrollFromSynergy(SInt32 delta) const
-{
-    // use mouse scrolling direction to invert
-    if (m_scrollDirectionMouse < 0)
-        return -delta;
-    return delta;
-}
-
-void
-MSWindowsScreen::updateScrollDirection()
-{
-    static const TCHAR* const touchpadScrollDirectionNames[] = {
-        _T("SOFTWARE"),
-        _T("Microsoft"),
-        _T("Windows"),
-        _T("CurrentVersion"),
-        _T("PrecisionTouchPad"),
-        NULL
-    };
-
-    if (m_shouldUpdateScrollDirection)
-    {
-        m_shouldUpdateScrollDirection = false;
-
-        std::thread scrollDirectionUpdateThread([&] {
-            HKEY key = ArchMiscWindows::openKey(HKEY_CURRENT_USER, touchpadScrollDirectionNames);
-            if (key)
-            {
-                DWORD scroll = ArchMiscWindows::readValueInt(key, _T("ScrollDirection"));
-                ArchMiscWindows::closeKey(key);
-                if (scroll == 0) m_scrollDirectionTouchpad = 1;
-                else m_scrollDirectionTouchpad = -1;
-            }
-        });
-        scrollDirectionUpdateThread.detach();
-    }
-}

src/lib/platform/MSWindowsScreen.h

@@ -141,7 +141,6 @@ public:
     virtual const String&    
                         getDropTarget() const;
     String              getSecureInputApp() const override;
-    void                updateScrollDirection() override;
 
 protected:
     // IPlatformScreen overrides
@@ -249,9 +248,6 @@ private: // HACK
     // send drag info and data back to server
     void                sendDragThread(void*);
 
-    SInt32              mapScrollToSynergy(SInt32 delta) const;
-    SInt32              mapScrollFromSynergy(SInt32 delta) const;
-
 private:
     struct HotKeyItem {
     public:
@@ -371,9 +367,5 @@ private:
     Thread*            m_sendDragThread;
 
     PrimaryKeyDownList    m_primaryKeyDownList;
-
+    MSWindowsPowerManager m_powerManager;
-    // -1 for natural scrolling direction, 1 otherwise
-    SInt32                    m_scrollDirectionMouse = 1;
-    SInt32                    m_scrollDirectionTouchpad = 1;
-    MSWindowsPowerManager     m_powerManager;
 };

src/lib/platform/OSXScreen.h

@@ -338,10 +338,6 @@ private:
     Thread*                m_getDropTargetThread;
     String                    m_dropTarget;
 
-    void                      updateScrollDirection() override;
-    // -1 for natural scrolling direction, 1 otherwise
-    SInt32                    m_scrollDirection = 1;
-    
 #if defined(MAC_OS_X_VERSION_10_7)
     Mutex*                    m_carbonLoopMutex;
     CondVar<bool>*            m_carbonLoopReady;

src/lib/platform/OSXScreen.mm

@@ -1460,7 +1460,7 @@ OSXScreen::mapScrollWheelToSynergy(SInt32 x) const
 {
 	// return accelerated scrolling
 	double d = (1.0 + getScrollSpeed()) * x;
-	return static_cast<SInt32>(m_scrollDirection * 120.0 * d);
+	return static_cast<SInt32>(120.0 * d);
 }
 
 SInt32
@@ -1468,7 +1468,8 @@ OSXScreen::mapScrollWheelFromSynergy(SInt32 x) const
 {
 	// use server's acceleration with a little boost since other platforms
 	// take one wheel step as a larger step than the mac does.
-	return static_cast<SInt32>(m_scrollDirection * 3.0 * x / 120.0);
+	auto result = static_cast<SInt32>(3.0 * x / 120.0);
+	return (result * ClientApp::instance().args().m_clientScrollDirection);
 }
 
 double
@@ -2214,17 +2215,6 @@ getProcessName(int pid)
     return buf;
 }
 
-void
-OSXScreen::updateScrollDirection()
-{
-	if(m_shouldUpdateScrollDirection)
-	{
-		LOG((CLOG_DEBUG "updated scrolling direction"));
-		m_scrollDirection = [[[NSUserDefaults standardUserDefaults] objectForKey:@"com.apple.swipescrolldirection"] boolValue] ? -1 : 1;
-		m_shouldUpdateScrollDirection = false;
-	}
-}
-
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 
 void

src/lib/platform/XWindowsScreen.cpp

@@ -25,6 +25,8 @@
 #include "platform/XWindowsUtil.h"
 #include "synergy/Clipboard.h"
 #include "synergy/KeyMap.h"
+#include "synergy/ClientApp.h"
+#include "synergy/ClientArgs.h"
 #include "synergy/XScreen.h"
 #include "synergy/ArgsBase.h"
 #include "synergy/App.h"
@@ -39,7 +41,6 @@
 #include <cstring>
 #include <cstdlib>
 #include <algorithm>
-#include <thread>
 #if X_DISPLAY_MISSING
 #	error X11 is required to build synergy
 #else
@@ -875,11 +876,7 @@ XWindowsScreen::fakeMouseWheel(SInt32, SInt32 yDelta) const
 		return;
 	}
 
-	// use mouse scroll direction for inversion
+	yDelta *= ClientApp::instance().args().m_clientScrollDirection;
-	if( m_scrollDirectionMouse < 0 )
-	{
-		yDelta = -yDelta;
-	}
 
 	// choose button depending on rotation direction
 	const unsigned int xButton = mapButtonToX(static_cast<ButtonID>(
@@ -1638,13 +1635,11 @@ XWindowsScreen::onMouseRelease(const XButtonEvent& xbutton)
 	}
 	else if (xbutton.button == 4) {
 		// wheel forward (away from user)
-		// invert for natural scroll setting
+		sendEvent(m_events->forIPrimaryScreen().wheel(), WheelInfo::alloc(0, 120));
-		sendEvent(m_events->forIPrimaryScreen().wheel(), WheelInfo::alloc(0, 120 * m_scrollDirectionMouse));
 	}
 	else if (xbutton.button == 5) {
 		// wheel backward (toward user)
-		// invert for natural scroll setting
+		sendEvent(m_events->forIPrimaryScreen().wheel(), WheelInfo::alloc(0, -120));
-		sendEvent(m_events->forIPrimaryScreen().wheel(), WheelInfo::alloc(0, -120 * m_scrollDirectionMouse));
 	}
 	// XXX -- support x-axis scrolling
 }
@@ -2169,28 +2164,3 @@ XWindowsScreen::selectXIRawMotion()
 	free(mask.mask);
 }
 #endif
-
-void
-XWindowsScreen::updateScrollDirection()
-{
-	if (m_shouldUpdateScrollDirection)
-	{
-		m_shouldUpdateScrollDirection = false;
-
-		std::thread scrollDirectionUpdateThread([this]{
-			std::string mouseScroll = ArchSystemUnix::runCommand("gsettings get org.gnome.desktop.peripherals.mouse natural-scroll");
-			if(mouseScroll == "false\n")
-				m_scrollDirectionMouse = 1;
-			else if(mouseScroll == "true\n")
-				m_scrollDirectionMouse = -1;
-
-			std::string touchpadScroll = ArchSystemUnix::runCommand("gsettings get org.gnome.desktop.peripherals.touchpad natural-scroll");
-			if(touchpadScroll == "false\n")
-				m_scrollDirectionTouchpad = 1;
-			else if(touchpadScroll == "true\n")
-				m_scrollDirectionTouchpad = -1;
-		});
-		scrollDirectionUpdateThread.detach();
-	}
-}
-

src/lib/platform/XWindowsScreen.h

@@ -88,8 +88,6 @@ public:
     virtual bool        isPrimary() const;
     String              getSecureInputApp() const override;
 
-    void                updateScrollDirection() override;
-
 protected:
     // IPlatformScreen overrides
     virtual void        handleSystemEvent(const Event&, void*);
@@ -255,9 +253,5 @@ private:
     // pointer to (singleton) screen.  this is only needed by
     // ioErrorHandler().
     static XWindowsScreen*    s_screen;
-
-    // -1 for natural scrolling direction, 1 otherwise
-    SInt32                    m_scrollDirectionMouse = 1;
-    SInt32                    m_scrollDirectionTouchpad = 1;
     XWindowsPowerManager      m_powerManager;
 };

src/lib/synergy/ArgParser.cpp

@@ -114,6 +114,9 @@ ArgParser::parseClientArgs(lib::synergy::ClientArgs& args, int argc, const char*
         else if (isArg(i, argc, argv, nullptr, "--sync-language")) {
             args.m_enableLangSync = true;
         }
+        else if (isArg(i, argc, argv, nullptr, "--invert-scroll")) {
+            args.m_clientScrollDirection = lib::synergy::ClientScrollDirection::INVERT_SERVER;
+        }
         else {
             if (i + 1 == argc) {
                 args.m_synergyAddress = argv[i];

src/lib/synergy/ClientApp.cpp

@@ -127,6 +127,7 @@ ClientApp::help()
         "Usage: %s"
         " [--yscroll <delta>]"
         " [--sync-language]"
+        " [--invert-scroll]"
         WINAPI_ARG
         HELP_SYS_ARGS
         HELP_COMMON_ARGS
@@ -140,6 +141,7 @@ ClientApp::help()
         "      --yscroll <delta>    defines the vertical scrolling delta, which is\n"
         "                             120 by default.\n"
         "      --sync-language      set this parameter to enable language synchronization.\n"
+        "      --invert-scroll      invert scroll direction on this computer.\n"
         HELP_COMMON_INFO_2
         "\n"
         "* marks defaults.\n"

src/lib/synergy/ClientArgs.h

@@ -23,6 +23,11 @@
 
 namespace lib {
     namespace synergy {
+        enum ClientScrollDirection {
+           SERVER = 1,
+           INVERT_SERVER = -1
+        };
+
         class ClientArgs : public ArgsBase {
 
             /// Public functions
@@ -32,10 +37,14 @@ namespace lib {
             ~ClientArgs() override;
 
         public:
-            int                  m_yscroll           = 0;
+            int                   m_yscroll        = 0;
-            bool                 m_enableLangSync    = false;       /// @brief Should keyboard input be in same language as on server
+            bool                  m_enableLangSync = false;       /// @brief Should keyboard input be in same language as on server
 
-        private:
+            /**
+             * @brief m_clientScrollDirection
+             * This option is responcible for scroll direction on client side.
+             */
+            ClientScrollDirection m_clientScrollDirection = ClientScrollDirection::SERVER;
 
         };
     }

src/lib/synergy/IPlatformScreen.h

@@ -139,20 +139,6 @@ public:
     */
     virtual String      getSecureInputApp() const = 0;
 
-    //! Allow updating wheel scrolling direction
-    /*!
-    Sets a flag to allow updating the scrolling direction automatically
-    when scrolling
-    */
-    virtual void        allowScrollDirectionUpdate() = 0;
-
-    //! Update the scrolling direction if allowed
-    /*!
-    If relevant flag is set should read a system settings to apply a
-    correct scrolling direction
-    */
-    virtual void        updateScrollDirection() = 0;
-
     //@}
     //! @name accessors
     //@{

src/lib/synergy/PlatformScreen.h

@@ -102,9 +102,6 @@ public:
     virtual const String&
                         getDropTarget() const { throw std::runtime_error("getDropTarget not implemented"); }
 
-    void                allowScrollDirectionUpdate() override { m_shouldUpdateScrollDirection = true; }
-    void                updateScrollDirection() override = 0;
-
 protected:
     //! Update mouse buttons
     /*!
@@ -127,5 +124,4 @@ protected:
     String                m_draggingFilename;
     bool                m_draggingStarted;
     bool                m_fakeDraggingStarted;
-    bool                m_shouldUpdateScrollDirection = false;
 };

src/lib/synergy/Screen.cpp

@@ -114,11 +114,6 @@ Screen::enter(KeyModifierMask toggleMask)
     // now on screen
     m_entered = true;
 
-    // Forcefully update scrolling direction
-    // Will keep clients updated when moving cursor
-    m_screen->allowScrollDirectionUpdate();
-    m_screen->updateScrollDirection();
-
     m_screen->enter();
     if (m_isPrimary) {
         enterPrimary();
@@ -134,11 +129,6 @@ Screen::leave()
     assert(m_entered == true);
     LOG((CLOG_INFO "leaving screen"));
 
-    // Forcefully update scrolling direction
-    // Will keep server updated when moving cursor
-    m_screen->allowScrollDirectionUpdate();
-    m_screen->updateScrollDirection();
-
     if (!m_screen->leave()) {
         return false;
     }
@@ -222,11 +212,6 @@ Screen::keyUp(KeyID, KeyModifierMask, KeyButton button)
 void
 Screen::mouseDown(ButtonID button)
 {
-	// No other convinient way to check if scroll direction was changed
-	// If mouse button is pressed is good enough indication to allow checking
-	// for scroll direction
-	m_screen->allowScrollDirectionUpdate();
-
     m_screen->fakeMouseButton(button, true);
 }
 
@@ -251,12 +236,9 @@ Screen::mouseRelativeMove(SInt32 dx, SInt32 dy)
 }
 
 void
-Screen::mouseWheel(SInt32 xDelta, SInt32 yDelta)
+Screen::mouseWheel(SInt32 xDelta, SInt32 yDelta) const
 {
     assert(!m_isPrimary);
-    // update scroll direction if necessary
-    m_screen->updateScrollDirection();
-
     m_screen->fakeMouseWheel(xDelta, yDelta);
 }
 

src/lib/synergy/Screen.h

@@ -177,7 +177,7 @@ public:
     to the right and negative for motion towards the user or to the left.
     Each wheel click should generate a delta of +/-120.
     */
-    void                mouseWheel(SInt32 xDelta, SInt32 yDelta);
+    void                mouseWheel(SInt32 xDelta, SInt32 yDelta) const;
 
     //! Notify of options changes
     /*!

src/test/unittests/synergy/ClientArgsParsingTests.cpp

@@ -68,6 +68,17 @@ TEST(ClientArgsParsingTests, parseClientArgs_setLangSync)
     EXPECT_TRUE(clientArgs.m_enableLangSync);
 }
 
+TEST(ClientArgsParsingTests, parseClientArgs_setInvertScroll)
+{
+    NiceMock<MockArgParser> argParser;
+    lib::synergy::ClientArgs clientArgs;
+    const int argc = 2;
+    std::array<const char*, argc> kLangCmd = { "stub", "--invert-scroll" };
+
+    argParser.parseClientArgs(clientArgs, argc, kLangCmd.data());
+    EXPECT_EQ(clientArgs.m_clientScrollDirection, lib::synergy::ClientScrollDirection::INVERT_SERVER);
+}
+
 TEST(ClientArgsParsingTests, parseClientArgs_setCommonArgs)
 {
     NiceMock<MockArgParser> argParser;