Adding powerline style tabs

kitty/config_data.py

@@ -679,10 +679,10 @@ Which edge to show the tab bar on, top or bottom'''))
 o('tab_bar_margin_width', 0.0, option_type=positive_float, long_text=_('''
 The margin to the left and right of the tab bar (in pts)'''))
 
-o('tab_bar_style', 'fade', option_type=choices('fade', 'separator', 'hidden'), long_text=_('''
-The tab bar style, can be one of: :code:`fade`, :code:`separator` or :code:`hidden`. In the fade style,
-each tab's edges fade into the background color, in the separator style, tabs are
-separated by a configurable separator.
+o('tab_bar_style', 'fade', option_type=choices('fade', 'separator', 'powerline', 'hidden'), long_text=_('''
+The tab bar style, can be one of: :code:`fade`, :code:`separator`, :code:`powerline`, or :code:`hidden`.
+In the fade style, each tab's edges fade into the background color, in the separator style, tabs are
+separated by a configurable separator, and the powerline shows the tabs as a continuous line.
 '''))
 
 o('tab_bar_min_tabs', 2, option_type=lambda x: max(1, positive_int(x)), long_text=_('''

kitty/tab_bar.py

@@ -18,7 +18,7 @@ from .rgb import alpha_blend, color_from_int
 TabBarData = namedtuple('TabBarData', 'title is_active needs_attention')
 DrawData = namedtuple(
     'DrawData', 'leading_spaces sep trailing_spaces bell_on_tab'
-    ' bell_fg alpha active_bg inactive_bg default_bg title_template')
+    ' bell_fg alpha active_fg active_bg inactive_fg inactive_bg default_bg title_template')
 
 
 def as_rgb(x):
@@ -41,7 +41,7 @@ def draw_title(draw_data, screen, tab, index):
     screen.draw(title)
 
 
-def draw_tab_with_separator(draw_data, screen, tab, before, max_title_length, index):
+def draw_tab_with_separator(draw_data, screen, tab, before, max_title_length, index, is_last):
     if draw_data.leading_spaces:
         screen.draw(' ' * draw_data.leading_spaces)
     draw_title(draw_data, screen, tab, index)
@@ -60,7 +60,7 @@ def draw_tab_with_separator(draw_data, screen, tab, before, max_title_length, in
     return end
 
 
-def draw_tab_with_fade(draw_data, screen, tab, before, max_title_length, index):
+def draw_tab_with_fade(draw_data, screen, tab, before, max_title_length, index, is_last):
     tab_bg = draw_data.active_bg if tab.is_active else draw_data.inactive_bg
     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:
@@ -87,6 +87,55 @@ def draw_tab_with_fade(draw_data, screen, tab, before, max_title_length, index):
     return end
 
 
+def draw_tab_with_powerline(draw_data, screen, tab, before, max_title_length, index, is_last):
+    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))
+
+    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('   ')
+        return screen.cursor.x
+
+    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(' ')
+        screen.cursor.fg = tab_fg
+    elif screen.cursor.x == 0:
+        screen.draw(' ')
+
+    if min_title_length >= max_title_length:
+        screen.draw('…')
+    else:
+        draw_title(draw_data, screen, tab, index)
+        extra = screen.cursor.x + 2 - before - max_title_length
+        if extra > 0 and extra + 1 < screen.cursor.x:
+            screen.cursor.x -= extra + 1
+            screen.draw('…')
+
+    if tab.is_active or is_last:
+        screen.draw(' ')
+        screen.cursor.fg = tab_bg
+        if is_last:
+            screen.cursor.bg = default_bg
+        else:
+            screen.cursor.bg = inactive_bg
+        screen.draw('')
+    else:
+        screen.draw(' ')
+
+    end = screen.cursor.x
+    screen.draw(' ')
+    return end
+
+
 class TabBar:
 
     def __init__(self, os_window_id, opts):
@@ -123,10 +172,16 @@ class TabBar:
         self.bell_fg = as_rgb(0xff0000)
         self.draw_data = DrawData(
             self.leading_spaces, self.sep, self.trailing_spaces, self.opts.bell_on_tab, self.bell_fg,
-            self.opts.tab_fade, self.opts.active_tab_background, self.opts.inactive_tab_background,
+            self.opts.tab_fade, self.opts.active_tab_foreground, self.opts.active_tab_background,
+            self.opts.inactive_tab_foreground, self.opts.inactive_tab_background,
             self.opts.background, self.opts.tab_title_template
         )
-        self.draw_func = draw_tab_with_separator if self.opts.tab_bar_style == 'separator' else draw_tab_with_fade
+        if self.opts.tab_bar_style == 'separator':
+            self.draw_func = draw_tab_with_separator
+        elif self.opts.tab_bar_style == 'powerline':
+            self.draw_func = draw_tab_with_powerline
+        else:
+            self.draw_func = draw_tab_with_fade
 
     def patch_colors(self, spec):
         if 'active_tab_foreground' in spec:
@@ -179,7 +234,7 @@ class TabBar:
             s.cursor.fg = self.active_fg if t.is_active else 0
             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)
+            end = self.draw_func(self.draw_data, s, t, before, max_title_length, i + 1, t is last_tab)
             cr.append((before, end))
             if s.cursor.x > s.columns - max_title_length and t is not last_tab:
                 s.draw('…')