Allow changing the cursor trail threshold time independently of input_delay

kitty/child-monitor.c

@@ -751,7 +751,7 @@ prepare_to_render_os_window(OSWindow *os_window, monotonic_t now, unsigned int *
                 WD.screen->cursor_render_info.is_focused = os_window->is_focused;
                 set_os_window_title_from_window(w, os_window);
                 *active_window_bg = window_bg;
-                if (OPT(enable_cursor_trail) && update_cursor_trail(&tab->cursor_trail, w, now, os_window)) {
+                if (OPT(cursor_trail) && update_cursor_trail(&tab->cursor_trail, w, now, os_window)) {
                     needs_render = true;
                     set_maximum_wait(OPT(repaint_delay));
                 }
@@ -812,7 +812,7 @@ render_prepared_os_window(OSWindow *os_window, unsigned int active_window_id, co
             w->cursor_opacity_at_last_render = WD.screen->cursor_render_info.opacity; w->last_cursor_shape = WD.screen->cursor_render_info.shape;
         }
     }
-    if (OPT(enable_cursor_trail) && tab->cursor_trail.needs_render) draw_cursor_trail(&tab->cursor_trail);
+    if (OPT(cursor_trail) && tab->cursor_trail.needs_render) draw_cursor_trail(&tab->cursor_trail);
     if (os_window->live_resize.in_progress) draw_resizing_text(os_window);
     swap_window_buffers(os_window);
     os_window->last_active_tab = os_window->active_tab; os_window->last_num_tabs = os_window->num_tabs; os_window->last_active_window_id = active_window_id;

kitty/cursor_trail.c

@@ -56,7 +56,7 @@ update_cursor_trail(CursorTrail *ct, Window *w, monotonic_t now, OSWindow *os_wi
             ct->corner_y[i] = EDGE(y, ci[i][1]);
         }
     }
-    else if (OPT(input_delay) < now - WD.screen->cursor->updated_at && ct->updated_at < now) {
+    else if (OPT(cursor_trail) < now - WD.screen->cursor->updated_at && ct->updated_at < now) {
         float cursor_center_x = (EDGE(x, 0) + EDGE(x, 1)) * 0.5f;
         float cursor_center_y = (EDGE(y, 0) + EDGE(y, 1)) * 0.5f;
         float cursor_diag_2 = norm(EDGE(x, 1) - EDGE(x, 0), EDGE(y, 1) - EDGE(y, 0)) * 0.5f;

kitty/options/definition.py

@@ -350,11 +350,17 @@ inactivity. Set to zero to never stop blinking.
 '''
     )
 
-opt('enable_cursor_trail', 'no',
+opt('cursor_trail', '0',
-    option_type='to_bool', ctype='bool',
+    option_type='positive_int', ctype='time-ms',
     long_text='''
-Enables or disables the cursor trail effect. When set to `yes`, a trailing
+Set this to a value larger than zero to enable a "cursor trail" animation.
-effect is rendered behind the cursor as it moves, creating a motion trail.
+This is an animation that shows a "trail" following the movement of the text cursor.
+It makes it easy to follow large cursor jumps and makes for a cool visual effect
+of the cursor zooming around the screen. The actual value of this option
+controls when the animation is trigerred. It is a number of milliseconds. The
+trail animation only follows cursors that have stayed in their position for longer
+than the specified number of milliseconds. This prevents trails from appearing
+for cursors that rapidly change their positions during UI updates in complex applications.
 '''
     )
 
@@ -362,8 +368,8 @@ opt('cursor_trail_decay', '0.1 0.3',
     option_type='cursor_trail_decay',
     ctype='!cursor_trail_decay',
     long_text='''
-Controls the decay times for the cursor trail effect when  :code:`enable_cursor_trail`
+Controls the decay times for the cursor trail effect when the :opt:`cursor_trail`
-is set to  :code:`yes`. This option accepts two positive float values specifying the
+is enabled. This option accepts two positive float values specifying the
 fastest and slowest decay times in seconds. The first value corresponds to the
 fastest decay time (minimum), and the second value corresponds to the slowest
 decay time (maximum). The second value must be equal to or greater than the

kitty/options/parse.py

@@ -931,6 +931,9 @@ class Parser:
     def cursor_text_color(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['cursor_text_color'] = cursor_text_color(val)
 
+    def cursor_trail(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
+        ans['cursor_trail'] = positive_int(val)
+
     def cursor_trail_decay(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['cursor_trail_decay'] = cursor_trail_decay(val)
 
@@ -966,9 +969,6 @@ class Parser:
     def enable_audio_bell(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['enable_audio_bell'] = to_bool(val)
 
-    def enable_cursor_trail(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
-        ans['enable_cursor_trail'] = to_bool(val)
-
     def enabled_layouts(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['enabled_layouts'] = to_layout_names(val)
 

kitty/options/to-c-generated.h

@@ -162,15 +162,15 @@ convert_from_opts_cursor_stop_blinking_after(PyObject *py_opts, Options *opts) {
 }
 
 static void
-convert_from_python_enable_cursor_trail(PyObject *val, Options *opts) {
+convert_from_python_cursor_trail(PyObject *val, Options *opts) {
-    opts->enable_cursor_trail = PyObject_IsTrue(val);
+    opts->cursor_trail = parse_ms_long_to_monotonic_t(val);
 }
 
 static void
-convert_from_opts_enable_cursor_trail(PyObject *py_opts, Options *opts) {
+convert_from_opts_cursor_trail(PyObject *py_opts, Options *opts) {
-    PyObject *ret = PyObject_GetAttrString(py_opts, "enable_cursor_trail");
+    PyObject *ret = PyObject_GetAttrString(py_opts, "cursor_trail");
     if (ret == NULL) return;
-    convert_from_python_enable_cursor_trail(ret, opts);
+    convert_from_python_cursor_trail(ret, opts);
     Py_DECREF(ret);
 }
 
@@ -1149,7 +1149,7 @@ convert_opts_from_python_opts(PyObject *py_opts, Options *opts) {
     if (PyErr_Occurred()) return false;
     convert_from_opts_cursor_stop_blinking_after(py_opts, opts);
     if (PyErr_Occurred()) return false;
-    convert_from_opts_enable_cursor_trail(py_opts, opts);
+    convert_from_opts_cursor_trail(py_opts, opts);
     if (PyErr_Occurred()) return false;
     convert_from_opts_cursor_trail_decay(py_opts, opts);
     if (PyErr_Occurred()) return false;

kitty/options/types.py

@@ -334,6 +334,7 @@ option_names = (  # {{{
  'cursor_shape_unfocused',
  'cursor_stop_blinking_after',
  'cursor_text_color',
+ 'cursor_trail',
  'cursor_trail_decay',
  'cursor_underline_thickness',
  'default_pointer_shape',
@@ -344,7 +345,6 @@ option_names = (  # {{{
  'dynamic_background_opacity',
  'editor',
  'enable_audio_bell',
- 'enable_cursor_trail',
  'enabled_layouts',
  'env',
  'exe_search_path',
@@ -512,6 +512,7 @@ class Options:
     cursor_shape_unfocused: int = 4
     cursor_stop_blinking_after: float = 15.0
     cursor_text_color: typing.Optional[kitty.fast_data_types.Color] = Color(17, 17, 17)
+    cursor_trail: int = 0
     cursor_trail_decay: typing.Tuple[float, float] = (0.1, 0.3)
     cursor_underline_thickness: float = 2.0
     default_pointer_shape: choices_for_default_pointer_shape = 'beam'
@@ -522,7 +523,6 @@ class Options:
     dynamic_background_opacity: bool = False
     editor: str = '.'
     enable_audio_bell: bool = True
-    enable_cursor_trail: bool = False
     enabled_layouts: typing.List[str] = ['fat', 'grid', 'horizontal', 'splits', 'stack', 'tall', 'vertical']
     file_transfer_confirmation_bypass: str = ''
     focus_follows_mouse: bool = False

kitty/state.h

@@ -46,7 +46,7 @@ typedef struct {
     CursorShape cursor_shape, cursor_shape_unfocused;
     float cursor_beam_thickness;
     float cursor_underline_thickness;
-    bool enable_cursor_trail;
+    monotonic_t cursor_trail;
     float cursor_trail_decay_fast;
     float cursor_trail_decay_slow;
     unsigned int url_style;