Feature: Implement Linux cursor type detection using XFixes extension

linux/ScreenHandler.h

@@ -12,6 +12,7 @@
 #include <atomic>
 #include <vector>
 #include <cstring>
+#include <cstdlib>
 #include <stdexcept>
 #include <memory>
 
@@ -389,6 +390,16 @@ static unsigned long VKtoKeySym(unsigned int vk)
     }
 }
 
+// XFixes cursor image structure (for cursor type detection)
+struct XFixesCursorImage {
+    short x, y;
+    unsigned short width, height;
+    unsigned short xhot, yhot;
+    unsigned long cursor_serial;
+    unsigned long* pixels;
+    // Atom cursor_name;  // Only in XFixes 2.0+
+};
+
 // X11 函数指针类型
 typedef Display* (*fn_XOpenDisplay)(const char*);
 typedef int (*fn_XCloseDisplay)(Display*);
@@ -405,12 +416,18 @@ typedef int (*fn_XSync)(Display*, int);
 typedef unsigned long (*fn_XKeysymToKeycode)(Display*, unsigned long);
 typedef int (*fn_XFlush)(Display*);
 typedef int (*fn_XClearArea)(Display*, Window, int, int, unsigned int, unsigned int, int);
+typedef int (*fn_XQueryPointer)(Display*, Window, Window*, Window*, int*, int*, int*, int*, unsigned int*);
+typedef int (*fn_XFree)(void*);
 
 // XTest 扩展函数指针类型（用于模拟鼠标/键盘输入）
 typedef int (*fn_XTestFakeMotionEvent)(Display*, int, int, int, unsigned long);
 typedef int (*fn_XTestFakeButtonEvent)(Display*, unsigned int, int, unsigned long);
 typedef int (*fn_XTestFakeKeyEvent)(Display*, unsigned int, int, unsigned long);
 
+// XFixes 扩展函数指针类型（用于光标类型检测）
+typedef int (*fn_XFixesQueryExtension)(Display*, int*, int*);
+typedef XFixesCursorImage* (*fn_XFixesGetCursorImage)(Display*);
+
 // X11 动态加载包装
 class X11Loader
 {
@@ -444,13 +461,19 @@ public:
     fn_XKeysymToKeycode pXKeysymToKeycode;
     fn_XFlush          pXFlush;
     fn_XClearArea      pXClearArea;
+    fn_XQueryPointer   pXQueryPointer;
+    fn_XFree           pXFree;
 
     // XTest 扩展（用于模拟输入）
     fn_XTestFakeMotionEvent pXTestFakeMotionEvent;
     fn_XTestFakeButtonEvent pXTestFakeButtonEvent;
     fn_XTestFakeKeyEvent    pXTestFakeKeyEvent;
 
-    X11Loader() : m_handle(nullptr), m_xtst_handle(nullptr)
+    // XFixes 扩展（用于光标类型检测）
+    fn_XFixesQueryExtension pXFixesQueryExtension;
+    fn_XFixesGetCursorImage pXFixesGetCursorImage;
+
+    X11Loader() : m_handle(nullptr), m_xtst_handle(nullptr), m_xfixes_handle(nullptr)
     {
         pXOpenDisplay = nullptr;
         pXCloseDisplay = nullptr;
@@ -471,9 +494,13 @@ public:
         pXKeysymToKeycode = nullptr;
         pXFlush = nullptr;
         pXClearArea = nullptr;
+        pXQueryPointer = nullptr;
+        pXFree = nullptr;
         pXTestFakeMotionEvent = nullptr;
         pXTestFakeButtonEvent = nullptr;
         pXTestFakeKeyEvent = nullptr;
+        pXFixesQueryExtension = nullptr;
+        pXFixesGetCursorImage = nullptr;
     }
 
     bool Load()
@@ -503,6 +530,8 @@ public:
         pXKeysymToKeycode = (fn_XKeysymToKeycode)dlsym(m_handle, "XKeysymToKeycode");
         pXFlush         = (fn_XFlush)dlsym(m_handle, "XFlush");
         pXClearArea     = (fn_XClearArea)dlsym(m_handle, "XClearArea");
+        pXQueryPointer  = (fn_XQueryPointer)dlsym(m_handle, "XQueryPointer");
+        pXFree          = (fn_XFree)dlsym(m_handle, "XFree");
 
         // 加载 XTest 扩展库（用于模拟鼠标/键盘输入）
         m_xtst_handle = dlopen("libXtst.so.6", RTLD_LAZY);
@@ -513,7 +542,15 @@ public:
             pXTestFakeKeyEvent    = (fn_XTestFakeKeyEvent)dlsym(m_xtst_handle, "XTestFakeKeyEvent");
         }
 
-        // 基本 X11 函数必须全部存在；XTest 函数可选（没有时无法控制输入）
+        // 加载 XFixes 扩展库（用于光标类型检测）
+        m_xfixes_handle = dlopen("libXfixes.so.3", RTLD_LAZY);
+        if (!m_xfixes_handle) m_xfixes_handle = dlopen("libXfixes.so", RTLD_LAZY);
+        if (m_xfixes_handle) {
+            pXFixesQueryExtension = (fn_XFixesQueryExtension)dlsym(m_xfixes_handle, "XFixesQueryExtension");
+            pXFixesGetCursorImage = (fn_XFixesGetCursorImage)dlsym(m_xfixes_handle, "XFixesGetCursorImage");
+        }
+
+        // 基本 X11 函数必须全部存在；XTest/XFixes 函数可选
         return pXOpenDisplay && pXCloseDisplay && pXGetImage && pXDestroyImage &&
                pXDefaultScreen && pXDisplayWidth && pXDisplayHeight && pXRootWindow &&
                pXSetErrorHandler && pXCreatePixmap && pXFreePixmap &&
@@ -527,8 +564,18 @@ public:
         return pXTestFakeMotionEvent && pXTestFakeButtonEvent && pXTestFakeKeyEvent;
     }
 
+    // 检查 XFixes 扩展是否可用
+    bool HasXFixes() const
+    {
+        return pXFixesGetCursorImage != nullptr;
+    }
+
     ~X11Loader()
     {
+        if (m_xfixes_handle) {
+            dlclose(m_xfixes_handle);
+            m_xfixes_handle = nullptr;
+        }
         if (m_xtst_handle) {
             dlclose(m_xtst_handle);
             m_xtst_handle = nullptr;
@@ -542,6 +589,7 @@ public:
 private:
     void* m_handle;
     void* m_xtst_handle;
+    void* m_xfixes_handle;
 };
 
 class ScreenHandler : public IOCPManager
@@ -1165,13 +1213,14 @@ private:
         uint8_t algo = m_bAlgorithm.load();
         memcpy(data, &algo, sizeof(uint8_t));
 
-        // 写入光标位置 (Linux 端简单置 0)
+        // 写入光标位置
         int32_t cursorX = 0, cursorY = 0;
+        GetCursorPosition(cursorX, cursorY);
         memcpy(data + 1, &cursorX, sizeof(int32_t));
         memcpy(data + 1 + sizeof(int32_t), &cursorY, sizeof(int32_t));
 
-        // 写入光标类型
+        // 写入光标类型 (使用 XFixes 检测)
-        uint8_t cursorType = 0;
+        uint8_t cursorType = GetCursorTypeIndex();
         memcpy(data + 1 + 2 * sizeof(int32_t), &cursorType, sizeof(uint8_t));
 
         uint32_t headerSize = 1 + 2 * sizeof(int32_t) + 1; // algo + cursor + cursorType
@@ -1231,9 +1280,10 @@ private:
         packet[1] = ALGORITHM_H264;
 
         int32_t cursorX = 0, cursorY = 0;
+        GetCursorPosition(cursorX, cursorY);
         memcpy(&packet[2], &cursorX, sizeof(int32_t));
         memcpy(&packet[6], &cursorY, sizeof(int32_t));
-        packet[10] = 0;  // cursorType
+        packet[10] = GetCursorTypeIndex();  // 使用 XFixes 检测光标类型
 
         memcpy(&packet[headerSize], encodedData, encodedSize);
         m_client->Send2Server((char*)packet.data(), packet.size());
@@ -1322,6 +1372,118 @@ private:
         return (uint64_t)ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
     }
 
+    // 获取光标位置
+    void GetCursorPosition(int32_t& x, int32_t& y)
+    {
+        x = 0;
+        y = 0;
+
+        // 检查是否正在运行和资源是否有效
+        if (!m_running.load() || m_destroyed.load()) {
+            static bool warned = false;
+            if (!warned) {
+                Mprintf("*** GetCursorPosition: skipped (running=%d, destroyed=%d)\n",
+                        m_running.load(), m_destroyed.load());
+                warned = true;
+            }
+            return;
+        }
+
+        Display* display = m_display;  // 局部拷贝
+        if (!display || !m_x11.pXQueryPointer) {
+            static bool warned = false;
+            if (!warned) {
+                Mprintf("*** GetCursorPosition: display=%p, pXQueryPointer=%p\n",
+                        (void*)display, (void*)m_x11.pXQueryPointer);
+                warned = true;
+            }
+            return;
+        }
+
+        Window root_return, child_return;
+        int root_x, root_y, win_x, win_y;
+        unsigned int mask;
+
+        if (m_x11.pXQueryPointer(display, m_root, &root_return, &child_return,
+                                  &root_x, &root_y, &win_x, &win_y, &mask)) {
+            x = root_x;
+            y = root_y;
+
+            // Clamp to screen bounds
+            if (x < 0) x = 0;
+            if (y < 0) y = 0;
+            if (x >= m_width) x = m_width - 1;
+            if (y >= m_height) y = m_height - 1;
+        }
+    }
+
+    // 获取光标类型索引（映射到 Windows 光标类型）
+    // Windows cursor type indices (from CursorInfo.h):
+    // 0: IDC_APPSTARTING, 1: IDC_ARROW, 2: IDC_CROSS, 3: IDC_HAND,
+    // 4: IDC_HELP, 5: IDC_IBEAM, 6: IDC_ICON, 7: IDC_NO,
+    // 8: IDC_SIZE, 9: IDC_SIZEALL, 10: IDC_SIZENESW, 11: IDC_SIZENS,
+    // 12: IDC_SIZENWSE, 13: IDC_SIZEWE, 14: IDC_UPARROW, 15: IDC_WAIT
+    uint8_t GetCursorTypeIndex()
+    {
+        // Cache result and throttle to avoid performance impact
+        static uint8_t cachedIndex = 1;  // Default: IDC_ARROW
+        static uint64_t lastCheckTime = 0;
+        static unsigned long lastCursorSerial = 0;
+
+        // Throttle: check at most every 100ms
+        uint64_t now = GetTickMs();
+        if ((now - lastCheckTime) < 100) {
+            return cachedIndex;
+        }
+        lastCheckTime = now;
+
+        // Check if XFixes is available and XFree is loaded
+        if (!m_x11.HasXFixes() || !m_x11.pXFree || !m_display) {
+            return 1;  // IDC_ARROW
+        }
+
+        // Get current cursor image
+        XFixesCursorImage* cursorImg = m_x11.pXFixesGetCursorImage(m_display);
+        if (!cursorImg) {
+            return cachedIndex;
+        }
+
+        // Check if cursor changed (using serial number)
+        if (cursorImg->cursor_serial == lastCursorSerial) {
+            // Cursor hasn't changed, use cached value
+            // Note: We need to free the cursor image
+            // XFixes allocates this with Xlib's allocator
+            m_x11.pXFree(cursorImg);
+            return cachedIndex;
+        }
+        lastCursorSerial = cursorImg->cursor_serial;
+
+        // Analyze cursor characteristics to determine type
+        uint8_t index = 1;  // Default to IDC_ARROW
+
+        unsigned short w = cursorImg->width;
+        unsigned short h = cursorImg->height;
+        unsigned short xhot = cursorImg->xhot;
+        unsigned short yhot = cursorImg->yhot;
+
+        // Heuristic-based cursor type detection (conservative approach):
+        // Only detect distinctive cursor types to minimize false positives
+
+        // IBEAM (text cursor): very narrow, tall cursor
+        if (w <= 8 && h >= 12 && xhot <= w/2 + 1) {
+            index = 5;  // IDC_IBEAM
+        }
+        // HAND (pointing): hotspot at top-left area (finger tip)
+        else if (w >= 18 && h >= 20 && xhot <= 10 && yhot <= 5) {
+            index = 3;  // IDC_HAND
+        }
+        // All other cursors default to ARROW
+
+        cachedIndex = index;
+        m_x11.pXFree(cursorImg);
+        return index;
+    }
+
     // 截屏主循环
     void CaptureLoop()
     {