fix(gui): horizontal scrolling in Linux (PR #2229)

* fix horizontal scrolling in linux

* improve code

---------

Co-authored-by: Skylot <118523+skylot@users.noreply.github.com>

jadx-gui/src/main/java/jadx/gui/ui/JadxEventQueue.java

@@ -0,0 +1,54 @@
+package jadx.gui.ui;
+
+import java.awt.AWTEvent;
+import java.awt.EventQueue;
+import java.awt.Toolkit;
+import java.awt.event.InputEvent;
+import java.awt.event.MouseEvent;
+import java.awt.event.MouseWheelEvent;
+
+import jadx.gui.utils.UiUtils;
+
+public class JadxEventQueue extends EventQueue {
+
+	private static final boolean IS_X_TOOLKIT = UiUtils.isXToolkit();
+
+	public static void register() {
+		if (IS_X_TOOLKIT) {
+			Toolkit.getDefaultToolkit().getSystemEventQueue().push(new JadxEventQueue());
+		}
+	}
+
+	private JadxEventQueue() {
+	}
+
+	@Override
+	protected void dispatchEvent(AWTEvent event) {
+		AWTEvent mappedEvent = mapEvent(event);
+		super.dispatchEvent(mappedEvent);
+	}
+
+	private static AWTEvent mapEvent(AWTEvent event) {
+		if (IS_X_TOOLKIT && event instanceof MouseEvent && ((MouseEvent) event).getButton() > 3) {
+			return mapXWindowMouseEvent((MouseEvent) event);
+		}
+		return event;
+	}
+
+	@SuppressWarnings({ "deprecation", "MagicConstant" })
+	private static AWTEvent mapXWindowMouseEvent(MouseEvent src) {
+		if (src.getButton() < 6) {
+			// buttons 4-5 come from touchpad, they must be converted to horizontal scrolling events
+			int modifiers = src.getModifiers() | InputEvent.SHIFT_DOWN_MASK;
+			return new MouseWheelEvent(src.getComponent(), MouseEvent.MOUSE_WHEEL, src.getWhen(), modifiers,
+					src.getX(), src.getY(), 0, false, MouseWheelEvent.WHEEL_UNIT_SCROLL,
+					src.getClickCount(), src.getButton() == 4 ? -1 : 1);
+		} else {
+			// Here we "shift" events with buttons `6` and `7` to similar events with buttons 4 and 5
+			// See `java.awt.InputEvent#BUTTON_DOWN_MASK`, 1<<14 is the 4th physical button, 1<<15 is the 5th.
+			int modifiers = src.getModifiers() | (1 << (8 + src.getButton()));
+			return new MouseEvent(src.getComponent(), src.getID(), src.getWhen(), modifiers,
+					src.getX(), src.getY(), 1, src.isPopupTrigger(), src.getButton() - 2);
+		}
+	}
+}

jadx-gui/src/main/java/jadx/gui/ui/MainWindow.java

@@ -250,6 +250,7 @@ public class MainWindow extends JFrame {
 		this.cacheManager = new CacheManager(settings);
 		this.shortcutsController = new ShortcutsController(settings);
 
+		JadxEventQueue.register();
 		resetCache();
 		FontUtils.registerBundledFonts();
 		setEditorTheme(settings.getEditorThemePath());

jadx-gui/src/main/java/jadx/gui/utils/SystemInfo.java

@@ -17,6 +17,7 @@ public class SystemInfo {
 	public static final boolean IS_WINDOWS = LOWER_OS_NAME.startsWith("windows");
 	public static final boolean IS_MAC = LOWER_OS_NAME.startsWith("mac");
 	public static final boolean IS_LINUX = LOWER_OS_NAME.startsWith("linux");
+	public static final boolean IS_UNIX = !IS_WINDOWS;
 
 	private SystemInfo() {
 	}

jadx-gui/src/main/java/jadx/gui/utils/UiUtils.java

@@ -394,6 +394,12 @@ public class UiUtils {
 		}
 	}
 
+	public static boolean isXToolkit() {
+		return SystemInfo.IS_UNIX
+				&& !SystemInfo.IS_MAC
+				&& "sun.awt.X11.XToolkit".equals(Toolkit.getDefaultToolkit().getClass().getName());
+	}
+
 	@TestOnly
 	public static void debugTimer(int periodInSeconds, Runnable action) {
 		if (!LOG.isDebugEnabled()) {