Added API and X11 implementation of cursor enter and leave callbacks.

src/input.c

@@ -436,3 +436,35 @@ GLFWAPI void glfwSetScrollCallback(GLFWscrollfun cbfun)
     _glfwLibrary.scrollCallback = cbfun;
 }
 
+
+//========================================================================
+// Set callback function for cursor enter events
+//========================================================================
+
+GLFWAPI void glfwSetCursorEnterCallback(GLFWcursorenterfun cbfun)
+{
+    if (!_glfwInitialized)
+    {
+        _glfwSetError(GLFW_NOT_INITIALIZED, NULL);
+        return;
+    }
+
+    _glfwLibrary.cursorEnterCallback = cbfun;
+}
+
+
+//========================================================================
+// Set callback function for cursor enter events
+//========================================================================
+
+GLFWAPI void glfwSetCursorLeaveCallback(GLFWcursorleavefun cbfun)
+{
+    if (!_glfwInitialized)
+    {
+        _glfwSetError(GLFW_NOT_INITIALIZED, NULL);
+        return;
+    }
+
+    _glfwLibrary.cursorLeaveCallback = cbfun;
+}
+

src/internal.h

@@ -240,6 +240,8 @@ struct _GLFWlibrary
     GLFWscrollfun        scrollCallback;
     GLFWkeyfun           keyCallback;
     GLFWcharfun          charCallback;
+    GLFWcursorenterfun   cursorEnterCallback;
+    GLFWcursorleavefun   cursorLeaveCallback;
 
     GLFWthreadmodel      threading;
     GLFWallocator        allocator;
@@ -352,6 +354,8 @@ void _glfwInputChar(_GLFWwindow* window, int character);
 void _glfwInputScroll(_GLFWwindow* window, int x, int y);
 void _glfwInputMouseClick(_GLFWwindow* window, int button, int action);
 void _glfwInputCursorMotion(_GLFWwindow* window, int x, int y);
+void _glfwInputCursorEnter(_GLFWwindow* window);
+void _glfwInputCursorLeave(_GLFWwindow* window);
 
 // OpenGL context helpers (opengl.c)
 int _glfwStringInExtensionString(const char* string, const GLubyte* extensions);

src/window.c

@@ -205,6 +205,25 @@ void _glfwInputWindowDamage(_GLFWwindow* window)
         _glfwLibrary.windowRefreshCallback(window);
 }
 
+//========================================================================
+// Register cursor enter events
+//========================================================================
+
+void _glfwInputCursorEnter(_GLFWwindow* window)
+{
+    if (_glfwLibrary.cursorEnterCallback)
+        _glfwLibrary.cursorEnterCallback(window);
+}
+
+//========================================================================
+// Register cursor leave events
+//========================================================================
+
+void _glfwInputCursorLeave(_GLFWwindow* window)
+{
+    if (_glfwLibrary.cursorLeaveCallback)
+        _glfwLibrary.cursorLeaveCallback(window);
+}
 
 //////////////////////////////////////////////////////////////////////////
 //////                        GLFW public API                       //////

src/x11_window.c

@@ -679,7 +679,8 @@ static GLboolean createWindow(_GLFWwindow* window,
         wa.border_pixel = 0;
         wa.event_mask = StructureNotifyMask | KeyPressMask | KeyReleaseMask |
             PointerMotionMask | ButtonPressMask | ButtonReleaseMask |
-            ExposureMask | FocusChangeMask | VisibilityChangeMask;
+            ExposureMask | FocusChangeMask | VisibilityChangeMask |
+            EnterWindowMask | LeaveWindowMask;
 
         if (wndconfig->mode == GLFW_WINDOWED)
         {
@@ -1180,6 +1181,37 @@ static void processSingleEvent(void)
             break;
         }
 
+        case EnterNotify:
+        {
+            // The mouse cursor enters the Window
+            window = findWindow(event.xcrossing.window);
+            if (window == NULL)
+            {
+                fprintf(stderr, "Cannot find GLFW window structure for EnterNotify event\n");
+                return;
+            }
+            if(window->cursorMode == GLFW_CURSOR_HIDDEN)
+            {
+                hideMouseCursor(window);
+            }
+            _glfwInputCursorEnter(window);
+            break;
+        }
+
+        case LeaveNotify:
+        {
+            // The mouse cursor leave the Window
+            window = findWindow(event.xcrossing.window);
+            if (window == NULL)
+            {
+                fprintf(stderr, "Cannot find GLFW window structure for LeaveNotify event\n");
+                return;
+            }
+            showMouseCursor(window);
+            _glfwInputCursorLeave(window);
+            break;
+        }
+
         case MotionNotify:
         {
             // The mouse cursor was moved