From c76db4bfb44ab9544dab49097a28e07ed06a93dd Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 25 Dec 2023 17:20:52 +0530
Subject: [PATCH] Wayland: Redraw titlebar title on font size change

Fixes #6945
---
 glfw/glfw.py         | 1 +
 glfw/wl_window.c     | 5 +++++
 kitty/glfw-wrapper.c | 3 +++
 kitty/glfw-wrapper.h | 4 ++++
 kitty/glfw.c         | 4 ++++
 kitty/state.c        | 3 +++
 6 files changed, 20 insertions(+)

diff --git a/glfw/glfw.py b/glfw/glfw.py
index 393e66a9e..f308657b9 100755
--- a/glfw/glfw.py
+++ b/glfw/glfw.py
@@ -262,6 +262,7 @@ def generate_wrappers(glfw_header: str) -> None:
     void glfwWaylandActivateWindow(GLFWwindow *handle, const char *activation_token)
     void glfwWaylandRunWithActivationToken(GLFWwindow *handle, GLFWactivationcallback cb, void *cb_data)
     bool glfwWaylandSetTitlebarColor(GLFWwindow *handle, uint32_t color, bool use_system_color)
+    void glfwWaylandRedrawCSDWindowTitle(GLFWwindow *handle)
     unsigned long long glfwDBusUserNotify(const char *app_name, const char* icon, const char *summary, const char *body, \
 const char *action_text, int32_t timeout, GLFWDBusnotificationcreatedfun callback, void *data)
     void glfwDBusSetUserNotificationHandler(GLFWDBusnotificationactivatedfun handler)
diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index 3775a4ef0..331e9cc12 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -2332,3 +2332,8 @@ GLFWAPI bool glfwWaylandSetTitlebarColor(GLFWwindow *handle, uint32_t color, boo
     }
     return false;
 }
+
+GLFWAPI void glfwWaylandRedrawCSDWindowTitle(GLFWwindow *handle) {
+    _GLFWwindow* window = (_GLFWwindow*) handle;
+    change_csd_title(window);
+}
diff --git a/kitty/glfw-wrapper.c b/kitty/glfw-wrapper.c
index f9a70d7db..f14c24cdc 100644
--- a/kitty/glfw-wrapper.c
+++ b/kitty/glfw-wrapper.c
@@ -479,6 +479,9 @@ load_glfw(const char* path) {
     *(void **) (&glfwWaylandSetTitlebarColor_impl) = dlsym(handle, "glfwWaylandSetTitlebarColor");
     if (glfwWaylandSetTitlebarColor_impl == NULL) dlerror(); // clear error indicator
 
+    *(void **) (&glfwWaylandRedrawCSDWindowTitle_impl) = dlsym(handle, "glfwWaylandRedrawCSDWindowTitle");
+    if (glfwWaylandRedrawCSDWindowTitle_impl == NULL) dlerror(); // clear error indicator
+
     *(void **) (&glfwDBusUserNotify_impl) = dlsym(handle, "glfwDBusUserNotify");
     if (glfwDBusUserNotify_impl == NULL) dlerror(); // clear error indicator
 
diff --git a/kitty/glfw-wrapper.h b/kitty/glfw-wrapper.h
index 88b3a2e71..4cd275e90 100644
--- a/kitty/glfw-wrapper.h
+++ b/kitty/glfw-wrapper.h
@@ -2291,6 +2291,10 @@ typedef bool (*glfwWaylandSetTitlebarColor_func)(GLFWwindow*, uint32_t, bool);
 GFW_EXTERN glfwWaylandSetTitlebarColor_func glfwWaylandSetTitlebarColor_impl;
 #define glfwWaylandSetTitlebarColor glfwWaylandSetTitlebarColor_impl
 
+typedef void (*glfwWaylandRedrawCSDWindowTitle_func)(GLFWwindow*);
+GFW_EXTERN glfwWaylandRedrawCSDWindowTitle_func glfwWaylandRedrawCSDWindowTitle_impl;
+#define glfwWaylandRedrawCSDWindowTitle glfwWaylandRedrawCSDWindowTitle_impl
+
 typedef unsigned long long (*glfwDBusUserNotify_func)(const char*, const char*, const char*, const char*, const char*, int32_t, GLFWDBusnotificationcreatedfun, void*);
 GFW_EXTERN glfwDBusUserNotify_func glfwDBusUserNotify_impl;
 #define glfwDBusUserNotify glfwDBusUserNotify_impl
diff --git a/kitty/glfw.c b/kitty/glfw.c
index e38bdcbc4..3e55723b0 100644
--- a/kitty/glfw.c
+++ b/kitty/glfw.c
@@ -1686,6 +1686,10 @@ request_window_attention(id_type kitty_window_id, bool audio_bell) {
 
 void
 set_os_window_title(OSWindow *w, const char *title) {
+    if (!title) {
+        if (global_state.is_wayland) glfwWaylandRedrawCSDWindowTitle(w->handle);
+        return;
+    }
     static char buf[2048];
     strip_csi_(title, buf, arraysz(buf));
     glfwSetWindowTitle(w->handle, buf);
diff --git a/kitty/state.c b/kitty/state.c
index bb1b47023..f10735665 100644
--- a/kitty/state.c
+++ b/kitty/state.c
@@ -1035,6 +1035,9 @@ PYWRAP1(os_window_font_size) {
                 }
             }
             os_window_update_size_increments(os_window);
+        // On Wayland with CSD title needs to be re-rendered in a different font size
+        if (os_window->window_title && global_state.is_wayland) set_os_window_title(os_window, NULL);
+
         }
         return Py_BuildValue("d", os_window->font_sz_in_pts);
     END_WITH_OS_WINDOW