A new remote control command to change tab color

Fixes #1287

docs/changelog.rst

@@ -22,6 +22,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Allow the user to supply a custom Python function to draw tab bar. See
   :opt:`tab_bar_style`
 
+- A new remote control command to :program:`change the tab color <kitty @
+  set-tab-color>` (:iss:`1287`)
+
 - Add support for reporting mouse events with pixel co-ordinates using the
   ``SGR_PIXEL_PROTOCOL`` introduced in xterm 359
 

kitty/rc/set_tab_color.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPLv3 Copyright: 2020, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+from typing import TYPE_CHECKING, Dict, Optional
+
+from kitty.rgb import to_color
+
+from .base import (
+    MATCH_TAB_OPTION, ArgsType, Boss, ParsingOfArgsFailed, PayloadGetType,
+    PayloadType, RCOptions, RemoteCommand, ResponseType, Window
+)
+
+if TYPE_CHECKING:
+    from kitty.cli_stub import SetTabColorRCOptions as CLIOptions
+
+
+valid_color_names = frozenset('active_fg active_bg inactive_fg inactive_bg'.split())
+
+
+def parse_colors(args: ArgsType) -> Dict[str, Optional[int]]:
+    ans: Dict[str, Optional[int]] = {}
+    for spec in args:
+        key, val = spec.split('=', 1)
+        key = key.lower()
+        if key.lower() not in valid_color_names:
+            raise KeyError(f'{key} is not a valid color name')
+        if val.lower() == 'none':
+            col: Optional[int] = None
+        else:
+            q = to_color(val, validate=True)
+            if q is not None:
+                col = int(q)
+        ans[key.lower()] = col
+    return ans
+
+
+class SetTabColor(RemoteCommand):
+
+    '''
+    colors+: An object mapping names to colors as 24-bit RGB integers. A color value of null indicates it should be unset.
+    match: Which tab to change the color of
+    self: Boolean indicating whether to use the tab of the window the command is run in
+    '''
+
+    short_desc = 'Change the color of the specified tab(s) in the tab bar'
+    desc = f'''
+{short_desc}
+
+The foreground and background colors when active and inactive can be overridden using this command. \
+The syntax for specifying colors is: active_fg=color active_bg=color inactive_fg=color \
+inactive_bg=color. Where color can be either a color name or a value of the form #rrggbb or \
+the keyword NONE to revert to using the default colors.
+'''
+    options_spec = MATCH_TAB_OPTION + '''\n
+--self
+type=bool-set
+If specified close the tab this command is run in, rather than the active tab.
+'''
+    argspec = 'COLORS'
+
+    def message_to_kitty(self, global_opts: RCOptions, opts: 'CLIOptions', args: ArgsType) -> PayloadType:
+        try:
+            colors = parse_colors(args)
+        except Exception as err:
+            raise ParsingOfArgsFailed(str(err)) from err
+        if not colors:
+            raise ParsingOfArgsFailed('No colors specified')
+        return {'match': opts.match, 'self': opts.self, 'colors': colors}
+
+    def response_from_kitty(self, boss: Boss, window: Optional[Window], payload_get: PayloadGetType) -> ResponseType:
+        colors = payload_get('colors')
+        s = {k: None if colors[k] is None else int(colors[k]) for k in valid_color_names if k in colors}
+        for tab in self.tabs_for_match_payload(boss, window, payload_get):
+            if tab:
+                for k, v in s.items():
+                    setattr(tab, k, v)
+                tab.mark_tab_bar_dirty()
+
+
+set_tab_color = SetTabColor()

kitty/tab_bar.py

@@ -30,6 +30,10 @@ class TabBarData(NamedTuple):
     num_window_groups: int
     layout_name: str
     has_activity_since_last_focus: bool
+    active_fg: Optional[int]
+    active_bg: Optional[int]
+    inactive_fg: Optional[int]
+    inactive_bg: Optional[int]
 
 
 class DrawData(NamedTuple):
@@ -50,6 +54,24 @@ class DrawData(NamedTuple):
     powerline_style: PowerlineStyle
     tab_bar_edge: EdgeLiteral
 
+    def tab_fg(self, tab: TabBarData) -> int:
+        if tab.is_active:
+            if tab.active_fg is not None:
+                return tab.active_fg
+            return int(self.active_fg)
+        if tab.inactive_fg is not None:
+            return tab.inactive_fg
+        return int(self.inactive_fg)
+
+    def tab_bg(self, tab: TabBarData) -> int:
+        if tab.is_active:
+            if tab.active_bg is not None:
+                return tab.active_bg
+            return int(self.active_bg)
+        if tab.inactive_bg is not None:
+            return tab.inactive_bg
+        return int(self.inactive_bg)
+
 
 def as_rgb(x: int) -> int:
     return (x << 8) | 2
@@ -122,7 +144,8 @@ class SupSub:
 
 
 class ExtraData:
-    pass
+    prev_tab: Optional[TabBarData] = None
+    next_tab: Optional[TabBarData] = None
 
 
 def draw_title(draw_data: DrawData, screen: Screen, tab: TabBarData, index: int) -> None:
@@ -183,7 +206,7 @@ def draw_tab_with_slant(
 ) -> int:
     orig_fg = screen.cursor.fg
     left_sep, right_sep = ('', '') if draw_data.tab_bar_edge == 'top' else ('', '')
-    tab_bg = as_rgb(color_as_int(draw_data.active_bg if tab.is_active else draw_data.inactive_bg))
+    tab_bg = screen.cursor.bg
     slant_fg = as_rgb(color_as_int(draw_data.default_bg))
 
     def draw_sep(which: str) -> None:
@@ -224,8 +247,6 @@ def draw_tab_with_separator(
     before: int, max_title_length: int, index: int, is_last: bool,
     extra_data: ExtraData
 ) -> int:
-    tab_bg = draw_data.active_bg if tab.is_active else draw_data.inactive_bg
-    screen.cursor.bg = as_rgb(color_as_int(tab_bg))
     if draw_data.leading_spaces:
         screen.draw(' ' * draw_data.leading_spaces)
     draw_title(draw_data, screen, tab, index)
@@ -252,12 +273,13 @@ def draw_tab_with_fade(
     before: int, max_title_length: int, index: int, is_last: bool,
     extra_data: ExtraData
 ) -> int:
-    tab_bg = draw_data.active_bg if tab.is_active else draw_data.inactive_bg
+    orig_bg = screen.cursor.bg
+    tab_bg = color_from_int(orig_bg >> 8)
     fade_colors = [as_rgb(color_as_int(alpha_blend(tab_bg, draw_data.default_bg, alpha))) for alpha in draw_data.alpha]
     for bg in fade_colors:
         screen.cursor.bg = bg
         screen.draw(' ')
-    screen.cursor.bg = as_rgb(color_as_int(tab_bg))
+    screen.cursor.bg = orig_bg
     draw_title(draw_data, screen, tab, index)
     extra = screen.cursor.x - before - max_title_length
     if extra > 0:
@@ -290,29 +312,21 @@ def draw_tab_with_powerline(
     before: int, max_title_length: int, index: int, is_last: bool,
     extra_data: ExtraData
 ) -> int:
-    tab_bg = as_rgb(color_as_int(draw_data.active_bg if tab.is_active else draw_data.inactive_bg))
-    tab_fg = as_rgb(color_as_int(draw_data.active_fg if tab.is_active else draw_data.inactive_fg))
-    inactive_bg = as_rgb(color_as_int(draw_data.inactive_bg))
-    default_bg = as_rgb(color_as_int(draw_data.default_bg))
+    tab_bg = screen.cursor.bg
+    tab_fg = screen.cursor.fg
+    default_bg = as_rgb(int(draw_data.default_bg))
+    if extra_data.next_tab:
+        next_tab_bg = as_rgb(draw_data.tab_bg(extra_data.next_tab))
+        needs_soft_separator = next_tab_bg == tab_bg
+    else:
+        next_tab_bg = default_bg
+        needs_soft_separator = False
 
-    separator_symbol, separator_alt_symbol = powerline_symbols.get(draw_data.powerline_style, ('', ''))
+    separator_symbol, soft_separator_symbol = powerline_symbols.get(draw_data.powerline_style, ('', ''))
     min_title_length = 1 + 2
-
-    if screen.cursor.x + min_title_length >= screen.columns:
-        screen.cursor.x -= 2
-        screen.cursor.bg = default_bg
-        screen.cursor.fg = inactive_bg
-        screen.draw(f'{separator_symbol}   ')
-        return screen.cursor.x
-
     start_draw = 2
-    if tab.is_active and screen.cursor.x >= 2:
-        screen.cursor.x -= 2
-        screen.cursor.fg = inactive_bg
-        screen.cursor.bg = tab_bg
-        screen.draw(f'{separator_symbol} ')
-        screen.cursor.fg = tab_fg
-    elif screen.cursor.x == 0:
+
+    if screen.cursor.x == 0:
         screen.cursor.bg = tab_bg
         screen.draw(' ')
         start_draw = 1
@@ -327,13 +341,10 @@ def draw_tab_with_powerline(
             screen.cursor.x -= extra + 1
             screen.draw('…')
 
-    if tab.is_active or is_last:
+    if not needs_soft_separator:
         screen.draw(' ')
         screen.cursor.fg = tab_bg
-        if is_last:
-            screen.cursor.bg = default_bg
-        else:
-            screen.cursor.bg = inactive_bg
+        screen.cursor.bg = next_tab_bg
         screen.draw(separator_symbol)
     else:
         prev_fg = screen.cursor.fg
@@ -344,7 +355,7 @@ def draw_tab_with_powerline(
             c2 = draw_data.inactive_bg.contrast(draw_data.inactive_fg)
             if c1 < c2:
                 screen.cursor.fg = default_bg
-        screen.draw(f' {separator_alt_symbol}')
+        screen.draw(f' {soft_separator_symbol}')
         screen.cursor.fg = prev_fg
 
     end = screen.cursor.x
@@ -516,8 +527,10 @@ class TabBar:
         ed = ExtraData()
 
         for i, t in enumerate(data):
-            s.cursor.bg = self.active_bg if t.is_active else 0
-            s.cursor.fg = self.active_fg if t.is_active else 0
+            ed.prev_tab = data[i - 1] if i > 0 else None
+            ed.next_tab = data[i + 1] if i + 1 < len(data) else None
+            s.cursor.bg = as_rgb(self.draw_data.tab_bg(t))
+            s.cursor.fg = as_rgb(self.draw_data.tab_fg(t))
             s.cursor.bold, s.cursor.italic = self.active_font_style if t.is_active else self.inactive_font_style
             before = s.cursor.x
             end = self.draw_func(self.draw_data, s, t, before, max_title_length, i + 1, t is last_tab, ed)

kitty/tabs.py

@@ -77,6 +77,11 @@ def add_active_id_to_history(items: Deque[int], item_id: int, maxlen: int = 64)
 
 class Tab:  # {{{
 
+    active_fg: Optional[int] = None
+    active_bg: Optional[int] = None
+    inactive_fg: Optional[int] = None
+    inactive_bg: Optional[int] = None
+
     def __init__(
         self,
         tab_manager: 'TabManager',
@@ -922,7 +927,8 @@ class TabManager:  # {{{
             ans.append(TabBarData(
                 title, t is at, needs_attention,
                 len(t), t.num_window_groups, t.current_layout.name or '',
-                has_activity_since_last_focus
+                has_activity_since_last_focus, t.active_fg, t.active_bg,
+                t.inactive_fg, t.inactive_bg
             ))
         return ans