Add a config option to hide window decorations under X11/Wayland

Fixes #607

docs/changelog.rst

@@ -47,7 +47,10 @@ Changelog
 - macOS: Fix the new OS window keyboard shortcut (:sc:`new_os_window`) not
   working if no kitty window currently has focus. (:iss:`524`)
 
-- Add a config option to set the EDITOR kitty uses (:iss:`580`)
+- Add a config option (:opt:`editor`) to set the EDITOR kitty uses (:iss:`580`)
+
+- Add a config option (:opt:`x11_hide_window_decorations`) to hide window
+  decorations under X11/Wayland (:iss:`607`)
 
 - Add an option to @set-window-title to make the title change non-permanent
   (:iss:`592`)

kitty/config_data.py

@@ -656,6 +656,14 @@ probably better off just hiding the titlebar with :opt:`macos_hide_titlebar`.
 o('macos_hide_titlebar', False, long_text=_('''
 Hide the kitty window's title bar on macOS.'''))
 
+
+o('x11_hide_window_decorations', False, long_text=_('''
+Hide the window decorations (title bar and window borders) on X11 and Wayland.
+Whether this works and exactly what effect it has depends on the window
+manager, as it is the job of the window manager/compositor to draw window
+decorations.'''))
+
+
 o('macos_option_as_alt', True, long_text=_('''
 Use the option key as an alt key. With this set to no, kitty will use
 the macOS native :kbd:`Option+Key` = unicode character behavior. This will

kitty/glfw.c

@@ -378,6 +378,9 @@ create_os_window(PyObject UNUSED *self, PyObject *args) {
 #ifndef __APPLE__
     glfwWindowHintString(GLFW_X11_INSTANCE_NAME, wm_class_name);
     glfwWindowHintString(GLFW_X11_CLASS_NAME, wm_class_class);
+    if (OPT(x11_hide_window_decorations)) {
+        glfwWindowHint(GLFW_DECORATED, GLFW_TRUE);
+    }
 #endif
 
     if (global_state.num_os_windows >= MAX_CHILDREN) {

kitty/state.c

@@ -385,6 +385,7 @@ PYWRAP1(set_options) {
     S(window_alert_on_bell, PyObject_IsTrue);
     S(macos_option_as_alt, PyObject_IsTrue);
     S(macos_hide_titlebar, PyObject_IsTrue);
+    S(x11_hide_window_decorations, PyObject_IsTrue);
     S(macos_hide_from_tasks, PyObject_IsTrue);
 
     PyObject *chars = PyObject_GetAttrString(opts, "select_by_word_characters");

kitty/state.h

@@ -23,7 +23,7 @@ typedef struct {
     color_type url_color, background, active_border_color, inactive_border_color, bell_border_color;
     double repaint_delay, input_delay;
     bool focus_follows_mouse;
-    bool macos_option_as_alt, macos_hide_titlebar, macos_hide_from_tasks;
+    bool macos_option_as_alt, macos_hide_titlebar, macos_hide_from_tasks, x11_hide_window_decorations;
     int adjust_line_height_px, adjust_column_width_px;
     float adjust_line_height_frac, adjust_column_width_frac;
     float background_opacity, dim_opacity;