Implement background blur for KDE on X11 as well

glfw/glfw.py

@@ -250,6 +250,7 @@ def generate_wrappers(glfw_header: str) -> None:
     uint32_t glfwGetCocoaKeyEquivalent(uint32_t glfw_key, int glfw_mods, int* cocoa_mods)
     void glfwCocoaRequestRenderFrame(GLFWwindow *w, GLFWcocoarenderframefun callback)
     int glfwCocoaSetBackgroundBlur(GLFWwindow *w, int blur_radius)
+    bool glfwSetX11WindowBlurred(GLFWwindow *w, bool enable_blur)
     void* glfwGetX11Display(void)
     int32_t glfwGetX11Window(GLFWwindow* window)
     void glfwSetPrimarySelectionString(GLFWwindow* window, const char* string)

glfw/glfw3.h

@@ -1047,6 +1047,7 @@ typedef enum {
  *  [window hint](@ref GLFW_X11_CLASS_NAME_hint).
  */
 #define GLFW_X11_INSTANCE_NAME      0x00024002
+#define GLFW_X11_BLUR               0x00024003
 
 #define GLFW_WAYLAND_APP_ID         0x00025001
 /*! @} */

glfw/internal.h

@@ -319,6 +319,7 @@ struct _GLFWwndconfig
     struct {
         char      className[256];
         char      instanceName[256];
+        int       enable_blur;
     } x11;
     struct {
         char      appId[256];

glfw/window.c

@@ -336,6 +336,7 @@ void glfwDefaultWindowHints(void)
     _glfw.hints.window.ns.color_space = 0;
     // no blur
     _glfw.hints.window.ns.blur_radius = 0;
+    _glfw.hints.window.x11.enable_blur = 0;
 }
 
 GLFWAPI void glfwWindowHint(int hint, int value)
@@ -422,6 +423,9 @@ GLFWAPI void glfwWindowHint(int hint, int value)
         case GLFW_COCOA_BLUR_RADIUS:
             _glfw.hints.window.ns.blur_radius = value;
             return;
+        case GLFW_X11_BLUR:
+            _glfw.hints.window.x11.enable_blur = value;
+            return;
         case GLFW_COCOA_GRAPHICS_SWITCHING:
             _glfw.hints.context.nsgl.offline = value ? true : false;
             return;

glfw/x11_init.c

@@ -651,6 +651,7 @@ int _glfwPlatformInit(void)
     _glfw.x11.root = RootWindow(_glfw.x11.display, _glfw.x11.screen);
     _glfw.x11.context = XUniqueContext();
     _glfw.x11.RESOURCE_MANAGER = XInternAtom(_glfw.x11.display, "RESOURCE_MANAGER", True);
+    _glfw.x11._KDE_NET_WM_BLUR_BEHIND_REGION = None;
     XSelectInput(_glfw.x11.display, _glfw.x11.root, PropertyChangeMask);
 
     _glfwGetSystemContentScaleX11(&_glfw.x11.contentScaleX, &_glfw.x11.contentScaleY, false);

glfw/x11_platform.h

@@ -299,6 +299,8 @@ typedef struct _GLFWlibraryX11
 
     // XRM database atom
     Atom            RESOURCE_MANAGER;
+    // KDE window blur
+    Atom _KDE_NET_WM_BLUR_BEHIND_REGION;
     // Atoms for MIME types
     AtomArray mime_atoms, clipboard_atoms, primary_atoms;
 

glfw/x11_window.c

@@ -64,6 +64,7 @@
 // covers GLX functions
 //
 static unsigned _glfwDispatchX11Events(void);
+GLFWAPI bool glfwSetX11WindowBlurred(GLFWwindow *w, bool enable_blur);
 
 static void
 handleEvents(monotonic_t timeout) {
@@ -713,6 +714,10 @@ static bool createNativeWindow(_GLFWwindow* window,
     _glfwPlatformGetWindowPos(window, &window->x11.xpos, &window->x11.ypos);
     _glfwPlatformGetWindowSize(window, &window->x11.width, &window->x11.height);
 
+    if (_glfw.hints.window.x11.enable_blur) {
+        glfwSetX11WindowBlurred((GLFWwindow*)window, 1);
+    }
+
     return true;
 }
 
@@ -2687,7 +2692,7 @@ _glfwDispatchX11Events(void) {
         if (window->x11.lastCursorPosX != width / 2 ||
             window->x11.lastCursorPosY != height / 2)
         {
-            _glfwPlatformSetCursorPos(window, width / 2, height / 2);
+            _glfwPlatformSetCursorPos(window, width / 2.f, height / 2.f);
         }
     }
 
@@ -3215,6 +3220,26 @@ GLFWAPI void glfwSetX11WindowAsDock(int32_t x11_window_id) {
                     PropModeReplace, (unsigned char*) &type, 1);
 }
 
+GLFWAPI bool glfwSetX11WindowBlurred(GLFWwindow *w, bool enable_blur) {
+    _GLFW_REQUIRE_INIT_OR_RETURN(0);
+    _GLFWwindow *window = (_GLFWwindow*)w;
+    if (_glfw.x11._KDE_NET_WM_BLUR_BEHIND_REGION == None) {
+        _glfw.x11._KDE_NET_WM_BLUR_BEHIND_REGION = XInternAtom(_glfw.x11.display, "_KDE_NET_WM_BLUR_BEHIND_REGION", False);
+    }
+    if (_glfw.x11._KDE_NET_WM_BLUR_BEHIND_REGION != None) {
+        uint32_t data = 0;
+        if (enable_blur) {
+            XChangeProperty(_glfw.x11.display, window->x11.handle, _glfw.x11._KDE_NET_WM_BLUR_BEHIND_REGION,
+                    XA_CARDINAL, 32, PropModeReplace, (unsigned char*) &data, 1);
+        } else {
+            XDeleteProperty(_glfw.x11.display, window->x11.handle, _glfw.x11._KDE_NET_WM_BLUR_BEHIND_REGION);
+        }
+        return true;
+    }
+    return false;
+}
+
+
 GLFWAPI void glfwSetX11WindowStrut(int32_t x11_window_id, uint32_t dimensions[12]) {
     _GLFW_REQUIRE_INIT();
     XChangeProperty(_glfw.x11.display, x11_window_id,

kitty/glfw-wrapper.c

@@ -446,6 +446,9 @@ load_glfw(const char* path) {
     *(void **) (&glfwCocoaSetBackgroundBlur_impl) = dlsym(handle, "glfwCocoaSetBackgroundBlur");
     if (glfwCocoaSetBackgroundBlur_impl == NULL) dlerror(); // clear error indicator
 
+    *(void **) (&glfwSetX11WindowBlurred_impl) = dlsym(handle, "glfwSetX11WindowBlurred");
+    if (glfwSetX11WindowBlurred_impl == NULL) dlerror(); // clear error indicator
+
     *(void **) (&glfwGetX11Display_impl) = dlsym(handle, "glfwGetX11Display");
     if (glfwGetX11Display_impl == NULL) dlerror(); // clear error indicator
 

kitty/glfw-wrapper.h

@@ -785,6 +785,7 @@ typedef enum {
  *  [window hint](@ref GLFW_X11_CLASS_NAME_hint).
  */
 #define GLFW_X11_INSTANCE_NAME      0x00024002
+#define GLFW_X11_BLUR               0x00024003
 
 #define GLFW_WAYLAND_APP_ID         0x00025001
 /*! @} */
@@ -2224,6 +2225,10 @@ typedef int (*glfwCocoaSetBackgroundBlur_func)(GLFWwindow*, int);
 GFW_EXTERN glfwCocoaSetBackgroundBlur_func glfwCocoaSetBackgroundBlur_impl;
 #define glfwCocoaSetBackgroundBlur glfwCocoaSetBackgroundBlur_impl
 
+typedef bool (*glfwSetX11WindowBlurred_func)(GLFWwindow*, bool);
+GFW_EXTERN glfwSetX11WindowBlurred_func glfwSetX11WindowBlurred_impl;
+#define glfwSetX11WindowBlurred glfwSetX11WindowBlurred_impl
+
 typedef void* (*glfwGetX11Display_func)(void);
 GFW_EXTERN glfwGetX11Display_func glfwGetX11Display_impl;
 #define glfwGetX11Display glfwGetX11Display_impl

kitty/glfw.c

@@ -900,14 +900,16 @@ create_os_window(PyObject UNUSED *self, PyObject *args, PyObject *kw) {
 #endif
     }
 
+    const bool set_blur = OPT(background_blur) > 0 && OPT(background_opacity) < 1.f;
 #ifdef __APPLE__
     glfwWindowHint(GLFW_COCOA_COLOR_SPACE, OPT(macos_colorspace));
-    if (OPT(background_blur) > 0 && OPT(background_opacity) < 1.f) {
+    if (set_blur) {
         glfwWindowHint(GLFW_COCOA_BLUR_RADIUS, MIN(OPT(background_blur), 128));
     } else {
         glfwWindowHint(GLFW_COCOA_BLUR_RADIUS, 0);
     }
 #else
+    if (!global_state.is_wayland) glfwWindowHint(GLFW_X11_BLUR, set_blur);
     glfwWindowHintString(GLFW_X11_INSTANCE_NAME, wm_class_name);
     glfwWindowHintString(GLFW_X11_CLASS_NAME, wm_class_class);
     glfwWindowHintString(GLFW_WAYLAND_APP_ID, wm_class_class);
@@ -1088,12 +1090,11 @@ os_window_update_size_increments(OSWindow *window) {
 
 void
 update_background_blur(OSWindow *os_window) {
+    const bool should_blur = os_window->background_opacity < 1.f && OPT(background_blur) > 0 && os_window->is_semi_transparent;
 #ifdef __APPLE__
-    int new_blur_radius = 0;
-    if (os_window->background_opacity < 1.f && OPT(background_blur) > -1) new_blur_radius = OPT(background_blur);
-    glfwCocoaSetBackgroundBlur(os_window->handle, new_blur_radius);
+    glfwCocoaSetBackgroundBlur(os_window->handle, should_blur ? OPT(background_blur) : 0);
 #else
-    (void)os_window;
+    if (!global_state.is_wayland) glfwSetX11WindowBlurred(os_window->handle, should_blur);
 #endif
 }
 

kitty/options/definition.py

@@ -1379,7 +1379,8 @@
 control the :italic:`blur radius` (amount of blurring). Setting it to too high
 a value will cause severe performance issues and/or rendering artifacts.
 Usually, values up to 64 work well. Note that this might cause performance issues,
-depending on how the platform implements it, so use with care.
+depending on how the platform implements it, so use with care. Currently supported
+on macOS and KDE/X11.
 ''')
 
 opt('background_image', 'none',