GLFW: Add support for mouse input transparency

From upstream: d285a9fdeb.

glfw/cocoa_window.m

@@ -1854,6 +1854,12 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, bool enabled)
         [window->ns.object setLevel:NSNormalWindowLevel];
 }
 
+void _glfwPlatformSetWindowMousePassthrough(_GLFWwindow* window, bool enabled)
+{
+    window->mousePassthrough = enabled;
+    [window->ns.object setIgnoresMouseEvents:enabled];
+}
+
 float _glfwPlatformGetWindowOpacity(_GLFWwindow* window)
 {
     return (float) [window->ns.object alphaValue];

glfw/glfw3.h

@@ -932,11 +932,19 @@ extern "C" {
  *  [window attribute](@ref GLFW_FOCUS_ON_SHOW_attrib).
  */
 #define GLFW_FOCUS_ON_SHOW          0x0002000C
+
+/*! @brief Forward mouse input to window behind.
+ *
+ *  Mouse input forwarding[window hint](@ref GLFW_MOUSE_PASSTHROUGH_hint) or
+ *  [window attribute](@ref GLFW_MOUSE_PASSTHROUGH_attrib).
+ */
+#define GLFW_MOUSE_PASSTHROUGH      0x0002000D
+
 /*! @brief Occlusion window attribute
  *
  *  Occlusion [window attribute](@ref GLFW_OCCLUDED_attrib).
  */
-#define GLFW_OCCLUDED               0x0002000D
+#define GLFW_OCCLUDED               0x0002000E
 /*! @brief Framebuffer bit depth hint.
  *
  *  Framebuffer bit depth [hint](@ref GLFW_RED_BITS).
@@ -3741,6 +3749,7 @@ GLFWAPI int glfwGetWindowAttrib(GLFWwindow* window, int attrib);
  *  [GLFW_FLOATING](@ref GLFW_FLOATING_attrib),
  *  [GLFW_AUTO_ICONIFY](@ref GLFW_AUTO_ICONIFY_attrib) and
  *  [GLFW_FOCUS_ON_SHOW](@ref GLFW_FOCUS_ON_SHOW_attrib).
+ *  [GLFW_MOUSE_PASSTHROUGH](@ref GLFW_MOUSE_PASSTHROUGH_attrib)
  *
  *  Some of these attributes are ignored for full screen windows.  The new
  *  value will take effect if the window is later made windowed.

glfw/internal.h

@@ -303,6 +303,7 @@ struct _GLFWwndconfig
     bool          maximized;
     bool          centerCursor;
     bool          focusOnShow;
+    bool          mousePassthrough;
     bool          scaleToMonitor;
     struct {
         bool      retina;
@@ -413,6 +414,7 @@ struct _GLFWwindow
     bool                autoIconify;
     bool                floating;
     bool                focusOnShow;
+    bool                mousePassthrough;
     bool                shouldClose;
     void*               userPointer;
     GLFWid              id;
@@ -717,6 +719,7 @@ float _glfwPlatformGetWindowOpacity(_GLFWwindow* window);
 void _glfwPlatformSetWindowResizable(_GLFWwindow* window, bool enabled);
 void _glfwPlatformSetWindowDecorated(_GLFWwindow* window, bool enabled);
 void _glfwPlatformSetWindowFloating(_GLFWwindow* window, bool enabled);
+void _glfwPlatformSetWindowMousePassthrough(_GLFWwindow* window, bool enabled);
 void _glfwPlatformSetWindowOpacity(_GLFWwindow* window, float opacity);
 void _glfwPlatformUpdateIMEState(_GLFWwindow *w, int which, int a, int b, int c, int d);
 

glfw/null_window.c

@@ -372,6 +372,10 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, bool enabled)
     window->null.floating = enabled;
 }
 
+void _glfwPlatformSetWindowMousePassthrough(_GLFWwindow* window UNUSED, bool enabled UNUSED)
+{
+}
+
 float _glfwPlatformGetWindowOpacity(_GLFWwindow* window)
 {
     return window->null.opacity;

glfw/window.c

@@ -290,6 +290,8 @@ GLFWAPI GLFWwindow* glfwCreateWindow(int width, int height,
         }
     }
 
+    _glfwPlatformSetWindowMousePassthrough(window, wndconfig.mousePassthrough);
+
     return (GLFWwindow*) window;
 }
 
@@ -422,6 +424,9 @@ GLFWAPI void glfwWindowHint(int hint, int value)
         case GLFW_FOCUS_ON_SHOW:
             _glfw.hints.window.focusOnShow = value ? true : false;
             return;
+        case GLFW_MOUSE_PASSTHROUGH:
+            _glfw.hints.window.mousePassthrough = value ? true : false;
+            return;
         case GLFW_CLIENT_API:
             _glfw.hints.context.client = value;
             return;
@@ -905,6 +910,8 @@ GLFWAPI int glfwGetWindowAttrib(GLFWwindow* handle, int attrib)
             return _glfwPlatformWindowHovered(window);
         case GLFW_FOCUS_ON_SHOW:
             return window->focusOnShow;
+        case GLFW_MOUSE_PASSTHROUGH:
+            return window->mousePassthrough;
         case GLFW_TRANSPARENT_FRAMEBUFFER:
             return _glfwPlatformFramebufferTransparent(window);
         case GLFW_OCCLUDED:
@@ -985,6 +992,8 @@ GLFWAPI void glfwSetWindowAttrib(GLFWwindow* handle, int attrib, int value)
     }
     else if (attrib == GLFW_FOCUS_ON_SHOW)
         window->focusOnShow = value;
+    else if (attrib == GLFW_MOUSE_PASSTHROUGH)
+        _glfwPlatformSetWindowMousePassthrough(window, value);
     else
         _glfwInputError(GLFW_INVALID_ENUM, "Invalid window attribute 0x%08X", attrib);
 }

glfw/wl_window.c

@@ -1269,6 +1269,23 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window UNUSED, bool enabled UNU
                     "Wayland: Window attribute setting not implemented yet");
 }
 
+void _glfwPlatformSetWindowMousePassthrough(_GLFWwindow* window, bool enabled)
+{
+    if (enabled == window->mousePassthrough)
+        return;
+
+    if (enabled)
+    {
+        struct wl_region* region = wl_compositor_create_region(_glfw.wl.compositor);
+        wl_surface_set_input_region(window->wl.surface, region);
+        wl_region_destroy(region);
+    }
+    else
+        wl_surface_set_input_region(window->wl.surface, 0);
+    wl_surface_commit(window->wl.surface);
+    window->mousePassthrough = enabled;
+}
+
 float _glfwPlatformGetWindowOpacity(_GLFWwindow* window UNUSED)
 {
     return 1.f;

glfw/x11_init.c

@@ -327,6 +327,30 @@ static bool initExtensions(void)
         }
     }
 
+#if defined(__CYGWIN__)
+    _glfw.x11.xshape.handle = _glfw_dlopen("libXext-6.so");
+#else
+    _glfw.x11.xshape.handle = _glfw_dlopen("libXext.so.6");
+#endif
+    if (_glfw.x11.xshape.handle)
+    {
+        glfw_dlsym(_glfw.x11.xshape.QueryExtension, _glfw.x11.xshape.handle, "XShapeQueryExtension");
+        glfw_dlsym(_glfw.x11.xshape.ShapeCombineRegion, _glfw.x11.xshape.handle, "XShapeCombineRegion");
+        glfw_dlsym(_glfw.x11.xshape.QueryVersion, _glfw.x11.xshape.handle, "XShapeQueryVersion");
+
+        if (XShapeQueryExtension(_glfw.x11.display,
+            &_glfw.x11.xshape.errorBase,
+            &_glfw.x11.xshape.eventBase))
+        {
+            if (XShapeQueryVersion(_glfw.x11.display,
+                &_glfw.x11.xshape.major,
+                &_glfw.x11.xshape.minor))
+            {
+                _glfw.x11.xshape.available = true;
+            }
+        }
+    }
+
     _glfw.x11.xkb.major = 1;
     _glfw.x11.xkb.minor = 0;
     _glfw.x11.xkb.available = XkbQueryExtension(_glfw.x11.display,

glfw/x11_platform.h

@@ -125,6 +125,13 @@ typedef XRenderPictFormat* (* PFN_XRenderFindVisualFormat)(Display*,Visual const
 #define XRenderQueryVersion _glfw.x11.xrender.QueryVersion
 #define XRenderFindVisualFormat _glfw.x11.xrender.FindVisualFormat
 
+typedef Bool (* PFN_XShapeQueryExtension)(Display*,int*,int*);
+typedef Status (* PFN_XShapeQueryVersion)(Display*dpy,int*,int*);
+typedef void (* PFN_XShapeCombineRegion)(Display*,Window,int,int,int,Region,int);
+#define XShapeQueryExtension _glfw.x11.xshape.QueryExtension
+#define XShapeQueryVersion _glfw.x11.xshape.QueryVersion
+#define XShapeCombineRegion _glfw.x11.xshape.ShapeCombineRegion
+
 typedef VkFlags VkXlibSurfaceCreateFlagsKHR;
 typedef VkFlags VkXcbSurfaceCreateFlagsKHR;
 
@@ -377,6 +384,18 @@ typedef struct _GLFWlibraryX11
         PFN_XRenderFindVisualFormat FindVisualFormat;
     } xrender;
 
+    struct {
+        bool        available;
+        void*       handle;
+        int         major;
+        int         minor;
+        int         eventBase;
+        int         errorBase;
+        PFN_XShapeQueryExtension QueryExtension;
+        PFN_XShapeCombineRegion ShapeCombineRegion;
+        PFN_XShapeQueryVersion QueryVersion;
+    } xshape;
+
     EventLoopData eventLoopData;
 
 } _GLFWlibraryX11;

glfw/x11_window.c

@@ -2586,6 +2586,32 @@ void _glfwPlatformSetWindowFloating(_GLFWwindow* window, bool enabled)
     XFlush(_glfw.x11.display);
 }
 
+void _glfwPlatformSetWindowMousePassthrough(_GLFWwindow* window, bool enabled)
+{
+    if (!_glfw.x11.xshape.available)
+        return;
+
+    if (enabled == window->mousePassthrough)
+        return;
+
+    int width = 0;
+    int height = 0;
+    if (!enabled)
+        _glfwPlatformGetWindowSize(window, &width, &height);
+
+    XRectangle rect;
+    rect.x = 0;
+    rect.y = 0;
+    rect.width = (unsigned short)width;
+    rect.height = (unsigned short)height;
+
+    Region region = XCreateRegion();
+    XUnionRectWithRegion(&rect, region, region);
+    XShapeCombineRegion(_glfw.x11.display, window->x11.handle, 2/*ShapeInput*/, 0, 0, region, 0/*ShapeSet*/);
+    XDestroyRegion(region);
+    window->mousePassthrough = enabled;
+}
+
 float _glfwPlatformGetWindowOpacity(_GLFWwindow* window)
 {
     float opacity = 1.f;

kitty/glfw-wrapper.h

@@ -670,11 +670,19 @@
  *  [window attribute](@ref GLFW_FOCUS_ON_SHOW_attrib).
  */
 #define GLFW_FOCUS_ON_SHOW          0x0002000C
+
+/*! @brief Forward mouse input to window behind.
+ *
+ *  Mouse input forwarding[window hint](@ref GLFW_MOUSE_PASSTHROUGH_hint) or
+ *  [window attribute](@ref GLFW_MOUSE_PASSTHROUGH_attrib).
+ */
+#define GLFW_MOUSE_PASSTHROUGH      0x0002000D
+
 /*! @brief Occlusion window attribute
  *
  *  Occlusion [window attribute](@ref GLFW_OCCLUDED_attrib).
  */
-#define GLFW_OCCLUDED               0x0002000D
+#define GLFW_OCCLUDED               0x0002000E
 /*! @brief Framebuffer bit depth hint.
  *
  *  Framebuffer bit depth [hint](@ref GLFW_RED_BITS).