macOS: Allow hiding the titlebar only instead of all window decorations

Thanks to @ntruong for writing cb8279ec54 and  6807411365, the code was very helpful.

kitty/cocoa_window.m

@@ -500,6 +500,26 @@ cocoa_hide_window_title(void *w)
     } // autoreleasepool
 }
 
+void
+cocoa_hide_titlebar(void *w)
+{
+    @autoreleasepool {
+
+    cocoa_hide_window_title(w);
+
+    NSWindow *window = (NSWindow*)w;
+
+    [window standardWindowButton: NSWindowCloseButton].hidden = true;
+    [window standardWindowButton: NSWindowMiniaturizeButton].hidden = true;
+    [window standardWindowButton: NSWindowZoomButton].hidden = true;
+
+    [window setTitlebarAppearsTransparent:YES];
+    [window setStyleMask:
+        [window styleMask] | NSWindowStyleMaskFullSizeContentView];
+
+    } // autoreleasepool
+}
+
 static PyMethodDef module_methods[] = {
     {"cocoa_get_lang", (PyCFunction)cocoa_get_lang, METH_NOARGS, ""},
     {"cocoa_set_new_window_trigger", (PyCFunction)cocoa_set_new_window_trigger, METH_VARARGS, ""},

kitty/config_data.py

@@ -662,8 +662,18 @@ Fade the text in inactive windows by the specified amount (a number between
 zero and one, with zero being fully faded).
 '''))
 
-o('hide_window_decorations', False, long_text=_('''
+
-Hide the window decorations (title-bar and window borders).
+def hide_window_decorations(x):
+    if x == 'titlebar-only':
+        return 0b10
+    elif to_bool(x):
+        return 0b01
+    return 0b00
+
+
+o('hide_window_decorations', 'no', option_type=hide_window_decorations, long_text=_('''
+Hide the window decorations (title-bar and window borders) with :code:`yes`.
+On macOS, :code:`titlebar-only` can be used to only hide the titlebar.
 Whether this works and exactly what effect it has depends on the
 window manager/operating system.
 '''))

kitty/glfw.c

@@ -14,6 +14,7 @@ extern bool cocoa_make_window_resizable(void *w, bool);
 extern void cocoa_focus_window(void *w);
 extern void cocoa_create_global_menu(void);
 extern void cocoa_hide_window_title(void *w);
+extern void cocoa_hide_titlebar(void *w);
 extern void cocoa_set_activation_policy(bool);
 extern void cocoa_set_titlebar_color(void *w, color_type color);
 extern bool cocoa_alt_option_key_pressed(unsigned long);
@@ -513,7 +514,7 @@ create_os_window(PyObject UNUSED *self, PyObject *args) {
         // We don't use depth and stencil buffers
         glfwWindowHint(GLFW_DEPTH_BITS, 0);
         glfwWindowHint(GLFW_STENCIL_BITS, 0);
-        if (OPT(hide_window_decorations)) glfwWindowHint(GLFW_DECORATED, false);
+        if (OPT(hide_window_decorations) & 1) glfwWindowHint(GLFW_DECORATED, false);
 #ifdef __APPLE__
         cocoa_set_activation_policy(OPT(macos_hide_from_tasks));
         glfwWindowHint(GLFW_COCOA_GRAPHICS_SWITCHING, true);
@@ -652,7 +653,9 @@ create_os_window(PyObject UNUSED *self, PyObject *args) {
     glfwSetDropCallback(glfw_window, drop_callback);
 #ifdef __APPLE__
     if (glfwGetCocoaWindow) {
-        if (!(OPT(macos_show_window_title_in) & WINDOW)) {
+        if (OPT(hide_window_decorations) & 2) {
+            cocoa_hide_titlebar(glfwGetCocoaWindow(glfw_window));
+        } else if (!(OPT(macos_show_window_title_in) & WINDOW)) {
             cocoa_hide_window_title(glfwGetCocoaWindow(glfw_window));
         }
         cocoa_make_window_resizable(glfwGetCocoaWindow(glfw_window), OPT(macos_window_resizable));

kitty/state.c

@@ -476,7 +476,7 @@ PYWRAP1(set_options) {
 #define SS(name, dest, convert) { GA(name); dest = convert(ret); Py_DECREF(ret); if (PyErr_Occurred()) return NULL; }
 #define S(name, convert) SS(name, OPT(name), convert)
     SS(kitty_mod, kitty_mod, PyLong_AsLong);
-    S(hide_window_decorations, PyObject_IsTrue);
+    S(hide_window_decorations, PyLong_AsUnsignedLong);
     S(visual_bell_duration, parse_s_double_to_monotonic_t);
     S(enable_audio_bell, PyObject_IsTrue);
     S(focus_follows_mouse, PyObject_IsTrue);

kitty/state.h

@@ -28,7 +28,8 @@ typedef struct {
     color_type url_color, background, foreground, active_border_color, inactive_border_color, bell_border_color;
     color_type mark1_foreground, mark1_background, mark2_foreground, mark2_background, mark3_foreground, mark3_background;
     monotonic_t repaint_delay, input_delay;
-    bool focus_follows_mouse, hide_window_decorations;
+    bool focus_follows_mouse;
+    unsigned int hide_window_decorations;
     bool macos_hide_from_tasks, macos_quit_when_last_window_closed, macos_window_resizable, macos_traditional_fullscreen;
     unsigned int macos_option_as_alt;
     float macos_thicken_font;