Change the window border color if a bell occurs in an unfocused window. Can be disabled by setting the bell_border_color to be the same as the inactive_border_color.

CHANGELOG.rst

@@ -6,9 +6,13 @@ kitty is a feature full, cross-platform, *fast*, GPU based terminal emulator.
 version 0.9.1 [future]
 ------------------------------
 
-- Show a bell on the tab if a bell occurs in one of the windows in the tab and
+- Show a bell symbol on the tab if a bell occurs in one of the windows in the tab and
   the window is not the currently focused window
 
+- Change the window border color if a bell occurs in an unfocused window. Can
+  be disabled by setting the bell_border_color to be the same as the
+  inactive_border_color.
+
 - macOS: Add support for dead keys
 
 - Unicode input: When searching by name search for prefix matches as well as

kitty/border_vertex.glsl

@@ -3,6 +3,7 @@ uniform uvec2 viewport;
 uniform vec3 default_bg;
 uniform vec3 active_border_color;
 uniform vec3 inactive_border_color;
+uniform vec3 bell_border_color;
 in uvec4 rect;  // left, top, right, bottom
 in uint rect_color;
 out vec3 color;
@@ -37,5 +38,5 @@ void main() {
     gl_Position = vec4(to_opengl(rect[pos.x], rect[pos.y]), 0, 1);
     int rc = int(rect_color);
     vec3 window_bg = vec3(to_color(rect_color >> 24), to_color(rect_color >> 16), to_color(rect_color >> 8));
-    color = float(1 & rc) * default_bg + float((2 & rc) >> 1) * active_border_color + float((4 & rc) >> 2) * inactive_border_color + float((8 & rc) >> 3) * window_bg;
+    color = float(1 & rc) * default_bg + float((2 & rc) >> 1) * active_border_color + float((4 & rc) >> 2) * inactive_border_color + float((8 & rc) >> 3) * window_bg + float((16 & rc) >> 4) * bell_border_color;
 }

kitty/borders.py

@@ -64,7 +64,7 @@ def __call__(
                 g = w.geometry
                 if bw > 0 and draw_window_borders:
                     # Draw the border rectangles
-                    color = 2 if w is active_window else 4
+                    color = 2 if w is active_window else (16 if w.needs_attention else 4)
                     border(
                         self.os_window_id, self.tab_id,
                         color, bw, g.left - fw, g.top - fw, g.right + fw,

kitty/config.py

@@ -359,7 +359,7 @@ def url_style(x):
 
 for name in (
     'foreground background cursor active_border_color inactive_border_color'
-    ' selection_foreground selection_background url_color'
+    ' selection_foreground selection_background url_color bell_border_color'
 ).split():
     type_map[name] = to_color
 for i in range(256):

kitty/kitty.conf

@@ -202,6 +202,9 @@ active_border_color #00ff00
 # The color for the border of inactive windows
 inactive_border_color #cccccc
 
+# The color for the border of inactive windows in which a bell has occurred
+bell_border_color #ff5a00
+
 # Fade the text in inactive windows by the specified amount (a number between
 # zero and one, with 0 being fully faded).
 inactive_text_alpha 1.0

kitty/shaders.c

@@ -486,7 +486,7 @@ draw_cursor(CursorRenderInfo *cursor, bool is_focused) {
 // }}}
 
 // Borders {{{
-enum BorderUniforms { BORDER_viewport, BORDER_background_opacity, BORDER_default_bg, BORDER_active_border_color, BORDER_inactive_border_color, NUM_BORDER_UNIFORMS };
+enum BorderUniforms { BORDER_viewport, BORDER_background_opacity, BORDER_default_bg, BORDER_active_border_color, BORDER_inactive_border_color, BORDER_bell_border_color, NUM_BORDER_UNIFORMS };
 static GLint border_uniform_locations[NUM_BORDER_UNIFORMS] = {0};
 
 static void
@@ -500,6 +500,7 @@ init_borders_program() {
         else if SET_LOC(default_bg);
         else if SET_LOC(active_border_color);
         else if SET_LOC(inactive_border_color);
+        else if SET_LOC(bell_border_color);
         else { fatal("Unknown uniform in borders program: %s", p->uniforms[i].name); return; }
     }
     if (left) { fatal("Left over uniforms in borders program"); return; }
@@ -536,6 +537,7 @@ draw_borders(ssize_t vao_idx, unsigned int num_border_rects, BorderRect *rect_bu
             glUniform1f(border_uniform_locations[BORDER_background_opacity], OPT(background_opacity));
             glUniform3f(border_uniform_locations[BORDER_active_border_color], CV3(OPT(active_border_color)));
             glUniform3f(border_uniform_locations[BORDER_inactive_border_color], CV3(OPT(inactive_border_color)));
+            glUniform3f(border_uniform_locations[BORDER_bell_border_color], CV3(OPT(bell_border_color)));
         }
         glUniform2ui(border_uniform_locations[BORDER_viewport], viewport_width, viewport_height);
         color_type default_bg = num_visible_windows > 1 ? OPT(background) : active_window_bg;

kitty/state.c

@@ -369,6 +369,7 @@ PYWRAP1(set_options) {
     S(background, color_as_int);
     S(active_border_color, color_as_int);
     S(inactive_border_color, color_as_int);
+    S(bell_border_color, color_as_int);
     S(repaint_delay, repaint_delay);
     S(input_delay, repaint_delay);
     S(sync_to_monitor, PyObject_IsTrue);

kitty/state.h

@@ -20,7 +20,7 @@ typedef struct {
     unsigned int rectangle_select_modifiers;
     unsigned int url_style;
     char_type select_by_word_characters[256]; size_t select_by_word_characters_count;
-    color_type url_color, background, active_border_color, inactive_border_color;
+    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;

kitty/tabs.py

@@ -88,6 +88,7 @@ def active_window_idx(self, val):
                 new_active_window.focus_changed(True)
             tm = self.tab_manager_ref()
             if tm is not None:
+                self.relayout_borders()
                 tm.update_tab_bar()
 
     @property
@@ -113,6 +114,7 @@ def title_changed(self, window):
     def on_bell(self, window):
         tm = self.tab_manager_ref()
         if tm is not None:
+            self.relayout_borders()
             tm.update_tab_bar()
 
     def visible_windows(self):