Allow middle clicking on a tab to close it

Fixes #4151

docs/changelog.rst

@@ -76,6 +76,8 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Unicode input kitten: Implement scrolling when more results are found than
   the available display space (:pull:`4068`)
 
+- Allow middle clicking on a tab to close it (:iss:`4151`)
+
 - The command line option ``--watcher`` has been deprecated in favor of the
   :opt:`watcher` option in :file:`kitty.conf`. It has the advantage of
   applying to all windows, not just the initially created ones. Note that

kitty/boss.py

@@ -591,10 +591,10 @@ class Boss:
             run_update_check(get_options().update_check_interval * 60 * 60)
             self.update_check_started = True
 
-    def activate_tab_at(self, os_window_id: int, x: int, is_double: bool = False) -> int:
+    def handle_click_on_tab(self, os_window_id: int, x: int, button: int, modifiers: int, action: int) -> int:
         tm = self.os_window_map.get(os_window_id)
         if tm is not None:
-            tm.activate_tab_at(x, is_double)
+            tm.handle_click_on_tab(x, button, modifiers, action)
 
     def on_window_resize(self, os_window_id: int, w: int, h: int, dpi_changed: bool) -> None:
         if dpi_changed:

kitty/fast_data_types.pyi

@@ -1254,3 +1254,7 @@ def num_users() -> int:
 
 def redirect_mouse_handling(yes: bool) -> None:
     pass
+
+
+def get_click_interval() -> float:
+    pass

kitty/glfw.c

@@ -1424,6 +1424,11 @@ dbus_send_notification(PyObject *self UNUSED, PyObject *args) {
     unsigned long long notification_id = glfwDBusUserNotify(app_name, icon, summary, body, action_name, timeout, dbus_notification_created_callback, NULL);
     return PyLong_FromUnsignedLongLong(notification_id);
 }
+
+static PyObject*
+get_click_interval(PyObject *self UNUSED, PyObject *args UNUSED) {
+    return PyFloat_FromDouble(monotonic_t_to_s_double(OPT(click_interval)));
+}
 #endif
 
 id_type
@@ -1472,6 +1477,7 @@ static PyMethodDef module_methods[] = {
     METHODB(glfw_window_hint, METH_VARARGS),
     METHODB(get_primary_selection, METH_NOARGS),
     METHODB(x11_display, METH_NOARGS),
+    METHODB(get_click_interval, METH_NOARGS),
     METHODB(x11_window_id, METH_O),
     METHODB(set_primary_selection, METH_VARARGS),
 #ifndef __APPLE__

kitty/mouse.c

@@ -515,13 +515,10 @@ HANDLER(handle_event) {
 }
 
 static void
-handle_tab_bar_mouse(int button, int UNUSED modifiers) {
-    static monotonic_t last_click_at = 0;
-    if (button != GLFW_MOUSE_BUTTON_LEFT || !global_state.callback_os_window->mouse_button_pressed[button]) return;
-    monotonic_t now = monotonic();
-    bool is_double = now - last_click_at <= OPT(click_interval);
-    last_click_at = is_double ? 0 : now;
-    call_boss(activate_tab_at, "KdO", global_state.callback_os_window->id, global_state.callback_os_window->mouse_x, is_double ? Py_True : Py_False);
+handle_tab_bar_mouse(int button, int modifiers, int action) {
+    if (button > -1) {  // dont report motion events, as they are expensive and useless
+        call_boss(handle_click_on_tab, "Kdiii", global_state.callback_os_window->id, global_state.callback_os_window->mouse_x, button, modifiers, action);
+    }
 }
 
 static bool
@@ -737,7 +734,7 @@ mouse_event(const int button, int modifiers, int action) {
     w = window_for_event(&window_idx, &in_tab_bar);
     if (in_tab_bar) {
         mouse_cursor_shape = HAND;
-        handle_tab_bar_mouse(button, modifiers);
+        handle_tab_bar_mouse(button, modifiers, action);
         debug("handled by tab bar\n");
     } else if (w) {
         debug("grabbed: %d\n", w->render_data.screen->modes.mouse_tracking_mode != 0);

kitty/tabs.py

@@ -8,6 +8,7 @@ from collections import deque
 from contextlib import suppress
 from functools import partial
 from operator import attrgetter
+from time import monotonic
 from typing import (
     Any, Deque, Dict, Generator, Iterable, Iterator, List, NamedTuple,
     Optional, Pattern, Sequence, Tuple, Union, cast
@@ -18,9 +19,11 @@ from .child import Child
 from .cli_stub import CLIOptions
 from .constants import appname, kitty_exe
 from .fast_data_types import (
-    add_tab, attach_window, detach_window, get_boss, get_options,
-    mark_tab_bar_dirty, next_window_id, remove_tab, remove_window, ring_bell,
-    set_active_tab, set_active_window, swap_tabs, sync_os_window_title
+    GLFW_MOUSE_BUTTON_LEFT, GLFW_MOUSE_BUTTON_MIDDLE, GLFW_PRESS, GLFW_RELEASE,
+    add_tab, attach_window, detach_window, get_boss, get_click_interval,
+    get_options, mark_tab_bar_dirty, next_window_id, remove_tab, remove_window,
+    ring_bell, set_active_tab, set_active_window, swap_tabs,
+    sync_os_window_title
 )
 from .layout.base import Layout
 from .layout.interface import create_layout_object_for, evict_cached_layouts
@@ -32,6 +35,14 @@ from .window import Watchers, Window, WindowDict
 from .window_list import WindowList
 
 
+class TabMouseEvent(NamedTuple):
+    button: int = -1
+    modifiers: int = 0
+    action: int = GLFW_PRESS
+    at: float = -1000.
+    tab_idx: Optional[int] = None
+
+
 class TabDict(TypedDict):
     id: int
     is_focused: bool
@@ -657,6 +668,7 @@ class TabManager:  # {{{
     def __init__(self, os_window_id: int, args: CLIOptions, wm_class: str, wm_name: str, startup_session: Optional[SessionType] = None):
         self.os_window_id = os_window_id
         self.wm_class = wm_class
+        self.recent_mouse_events: Deque[TabMouseEvent] = deque()
         self.wm_name = wm_name
         self.last_active_tab_id = None
         self.args = args
@@ -965,13 +977,32 @@ class TabManager:  # {{{
             ))
         return ans
 
-    def activate_tab_at(self, x: int, is_double: bool = False) -> None:
+    def handle_click_on_tab(self, x: int, button: int, modifiers: int, action: int) -> None:
         i = self.tab_bar.tab_at(x)
+        now = monotonic()
         if i is None:
-            if is_double:
-                self.new_tab()
+            if button == GLFW_MOUSE_BUTTON_LEFT and action == GLFW_PRESS and len(self.recent_mouse_events) > 1:
+                ci = get_click_interval()
+                prev, prev2 = self.recent_mouse_events[-1], self.recent_mouse_events[-2]
+                if (
+                    prev.button == button and prev2.button == button and
+                    prev.action == GLFW_RELEASE and prev2.action == GLFW_PRESS and
+                    prev.tab_idx is None and prev2.tab_idx is None and
+                    now - prev.at <= ci and now - prev2.at <= 2 * ci
+                ):  # double click
+                    self.new_tab()
+                    self.recent_mouse_events.clear()
+                    return
         else:
-            self.set_active_tab_idx(i)
+            if action == GLFW_PRESS:
+                if button == GLFW_MOUSE_BUTTON_LEFT:
+                    self.set_active_tab_idx(i)
+                elif button == GLFW_MOUSE_BUTTON_MIDDLE:
+                    tab = self.tabs[i]
+                    get_boss().close_tab(tab)
+        self.recent_mouse_events.append(TabMouseEvent(button, modifiers, action, now, i))
+        if len(self.recent_mouse_events) > 5:
+            self.recent_mouse_events.popleft()
 
     @property
     def tab_bar_rects(self) -> Tuple[Border, ...]: