From 05c050b81e0687b25fc6e2a11d113c65b894fa5c Mon Sep 17 00:00:00 2001
From: sithlord48 <sithlord48@gmail.com>
Date: Mon, 2 Feb 2026 15:36:39 -0500
Subject: [PATCH] fix: handle back mouse on xwindows and windows based on :
 https://github.com/debauchee/barrier/commit/9f15b1bcf2953acf609f7580463bf13cdb23d008
 fixes: #5682

---
 src/lib/deskflow/MouseTypes.h        |  2 +-
 src/lib/platform/MSWindowsDesks.cpp  |  4 +-
 src/lib/platform/MSWindowsScreen.cpp |  4 +-
 src/lib/platform/MSWindowsScreen.h   |  2 +-
 src/lib/platform/XWindowsScreen.cpp  | 57 ++++++++++------------------
 5 files changed, 26 insertions(+), 43 deletions(-)

diff --git a/src/lib/deskflow/MouseTypes.h b/src/lib/deskflow/MouseTypes.h
index 0c045eabe..22cbd17df 100644
--- a/src/lib/deskflow/MouseTypes.h
+++ b/src/lib/deskflow/MouseTypes.h
@@ -28,4 +28,4 @@ static const ButtonID kMacButtonRight = 2;
 static const ButtonID kMacButtonMiddle = 3;
 //@}
 
-static const uint8_t NumButtonIDs = 5;
+static const uint8_t NumButtonIDs = 6;
diff --git a/src/lib/platform/MSWindowsDesks.cpp b/src/lib/platform/MSWindowsDesks.cpp
index e6a02544a..37f339beb 100644
--- a/src/lib/platform/MSWindowsDesks.cpp
+++ b/src/lib/platform/MSWindowsDesks.cpp
@@ -272,12 +272,12 @@ void MSWindowsDesks::fakeMouseButton(ButtonID button, bool press)
     flags = press ? MOUSEEVENTF_RIGHTDOWN : MOUSEEVENTF_RIGHTUP;
     break;
 
-  case kButtonExtra0 + 0:
+  case kButtonExtra0:
     data = XBUTTON1;
     flags = press ? MOUSEEVENTF_XDOWN : MOUSEEVENTF_XUP;
     break;
 
-  case kButtonExtra0 + 1:
+  case kButtonExtra1:
     data = XBUTTON2;
     flags = press ? MOUSEEVENTF_XDOWN : MOUSEEVENTF_XUP;
     break;
diff --git a/src/lib/platform/MSWindowsScreen.cpp b/src/lib/platform/MSWindowsScreen.cpp
index 57afe583d..0a318abff 100644
--- a/src/lib/platform/MSWindowsScreen.cpp
+++ b/src/lib/platform/MSWindowsScreen.cpp
@@ -1506,13 +1506,13 @@ ButtonID MSWindowsScreen::mapButtonFromEvent(WPARAM msg, LPARAM button) const
     switch (button) {
     case XBUTTON1:
       if (GetSystemMetrics(SM_CMOUSEBUTTONS) >= 4) {
-        return kButtonExtra0 + 0;
+        return kButtonExtra0;
       }
       break;
 
     case XBUTTON2:
       if (GetSystemMetrics(SM_CMOUSEBUTTONS) >= 5) {
-        return kButtonExtra0 + 1;
+        return kButtonExtra1;
       }
       break;
     }
diff --git a/src/lib/platform/MSWindowsScreen.h b/src/lib/platform/MSWindowsScreen.h
index 5430c3dba..ce2458df6 100644
--- a/src/lib/platform/MSWindowsScreen.h
+++ b/src/lib/platform/MSWindowsScreen.h
@@ -318,7 +318,7 @@ private:
   HotKeyToIDMap m_hotKeyToIDMap;
 
   // map of button state
-  bool m_buttons[1 + kButtonExtra0 + 1];
+  bool m_buttons[NumButtonIDs];
 
   // m_hasMouse is true if there's a mouse attached to the system or
   // mouse keys is simulating one.  we track this so we can force the
diff --git a/src/lib/platform/XWindowsScreen.cpp b/src/lib/platform/XWindowsScreen.cpp
index a52a59a16..4e708e25e 100644
--- a/src/lib/platform/XWindowsScreen.cpp
+++ b/src/lib/platform/XWindowsScreen.cpp
@@ -1743,51 +1743,34 @@ KeyID XWindowsScreen::mapKeyFromX(XKeyEvent *event) const
 
 ButtonID XWindowsScreen::mapButtonFromX(const XButtonEvent *event) const
 {
-  unsigned int button = event->button;
-
-  // first three buttons map to 1, 2, 3 (kButtonLeft, Middle, Right)
-  if (button >= 1 && button <= 3) {
-    return static_cast<ButtonID>(button);
-  }
-
-  // buttons 4 and 5 are ignored here.  they're used for the wheel.
-  // buttons 6, 7, etc and up map to 4, 5, etc.
-  else if (button >= 6) {
-    return static_cast<ButtonID>(button - 2);
-  }
-
-  // unknown button
-  else {
+  switch (unsigned int button = event->button; button) {
+  case 1:
+  case 2:
+  case 3:
+    return static_cast<ButtonID>(button); // Handle Left, Middle and Right buttons
+  case 8:
+    return kButtonExtra0; // Mouse 4
+  case 9:
+    return kButtonExtra1; // Mouse 5
+  default:
     return kButtonNone;
   }
 }
 
 unsigned int XWindowsScreen::mapButtonToX(ButtonID id) const
 {
-  // map button -1 to button 4 (+wheel)
-  if (id == static_cast<ButtonID>(-1)) {
-    id = 4;
-  }
-
-  // map button -2 to button 5 (-wheel)
-  else if (id == static_cast<ButtonID>(-2)) {
-    id = 5;
-  }
-
-  // map buttons 4, 5, etc. to 6, 7, etc. to make room for buttons
-  // 4 and 5 used to simulate the mouse wheel.
-  else if (id >= 4) {
-    id += 2;
-  }
-
-  // check button is in legal range
-  if (id < 1 || id > m_buttons.size()) {
-    // out of range
+  switch (id) {
+  case kButtonLeft:
+  case kButtonRight:
+  case kButtonMiddle:
+    return static_cast<uint>(id);
+  case kButtonExtra0:
+    return 8;
+  case kButtonExtra1:
+    return 9;
+  default:
     return 0;
   }
-
-  // map button
-  return static_cast<unsigned int>(id);
 }
 
 void XWindowsScreen::warpCursorNoFlush(int32_t x, int32_t y)