A new "slant" style for the tab bar

docs/changelog.rst

@@ -4,6 +4,12 @@ Changelog
 |kitty| is a feature-rich, cross-platform, *fast*, GPU based terminal.
 To update |kitty|, :doc:`follow the instructions <binary>`.
 
+0.23.0 [future]
+----------------------
+
+- A new style for the tab bar that makes tabs looks like the tabs in a physical
+  tabbed file, see :opt:`tab_bar_style`
+
 0.22.2 [2021-08-02]
 ----------------------
 

kitty/options/definition.py

@@ -872,15 +872,16 @@ tab.
 
 
 opt('tab_bar_style', 'fade',
-    choices=('fade', 'hidden', 'powerline', 'separator'), ctype='!tab_bar_style',
+    choices=('fade', 'hidden', 'powerline', 'separator', 'slant'), ctype='!tab_bar_style',
     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
+into the background color, in the slant style tabs look like the tabs in file
-configurable separator, and the powerline shows the tabs as a continuous line.
+folder, in the separator style, tabs are separated by a configurable separator,
-If you use the hidden style, you might want to create a mapping for the
+the powerline shows the tabs as a continuous line. If you use the hidden
-:ref:`action-select_tab` action which presents you with a list of tabs
+style, you might want to create a mapping for the :ref:`action-select_tab`
-and allows for easy switching to a tab.
+action which presents you with a list of tabs and allows for easy switching to
+a tab.
 '''
     )
 

kitty/options/parse.py

@@ -1167,7 +1167,7 @@ class Parser:
             raise ValueError(f"The value {val} is not a valid choice for tab_bar_style")
         ans["tab_bar_style"] = val
 
-    choices_for_tab_bar_style = frozenset(('fade', 'hidden', 'powerline', 'separator'))
+    choices_for_tab_bar_style = frozenset(('fade', 'hidden', 'powerline', 'separator', 'slant'))
 
     def tab_fade(self, val: str, ans: typing.Dict[str, typing.Any]) -> None:
         ans['tab_fade'] = tab_fade(val)

kitty/options/types.py

@@ -23,7 +23,7 @@ if typing.TYPE_CHECKING:
     choices_for_pointer_shape_when_dragging = typing.Literal['arrow', 'beam', 'hand']
     choices_for_pointer_shape_when_grabbed = typing.Literal['arrow', 'beam', 'hand']
     choices_for_strip_trailing_spaces = typing.Literal['always', 'never', 'smart']
-    choices_for_tab_bar_style = typing.Literal['fade', 'hidden', 'powerline', 'separator']
+    choices_for_tab_bar_style = typing.Literal['fade', 'hidden', 'powerline', 'separator', 'slant']
     choices_for_tab_powerline_style = typing.Literal['angled', 'round', 'slanted']
     choices_for_tab_switch_strategy = typing.Literal['last', 'left', 'previous', 'right']
 else:

kitty/tab_bar.py

@@ -13,7 +13,7 @@ from .fast_data_types import (
 from .layout.base import Rect
 from .rgb import Color, alpha_blend, color_as_sgr, color_from_int, to_color
 from .types import WindowGeometry, run_once
-from .typing import PowerlineStyle
+from .typing import PowerlineStyle, EdgeLiteral
 from .utils import color_as_int, log_error
 from .window import calculate_gl_geometry
 
@@ -44,6 +44,7 @@ class DrawData(NamedTuple):
     active_title_template: Optional[str]
     tab_activity_symbol: Optional[str]
     powerline_style: PowerlineStyle
+    tab_bar_edge: EdgeLiteral
 
 
 def as_rgb(x: int) -> int:
@@ -164,6 +165,44 @@ def draw_title(draw_data: DrawData, screen: Screen, tab: TabBarData, index: int)
         screen.draw(title)
 
 
+def draw_tab_with_slant(draw_data: DrawData, screen: Screen, tab: TabBarData, before: int, max_title_length: int, index: int, is_last: bool) -> int:
+    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))
+    slant_fg = as_rgb(color_as_int(draw_data.default_bg))
+
+    def draw_sep(which: str) -> None:
+        screen.cursor.bg = tab_bg
+        screen.cursor.fg = slant_fg
+        screen.draw(which)
+        screen.cursor.bg = tab_bg
+        screen.cursor.fg = 0
+
+    max_title_length += 1
+    if max_title_length <= 1:
+        screen.draw('…')
+    elif max_title_length == 2:
+        screen.draw('…|')
+    elif max_title_length < 6:
+        draw_sep(left_sep)
+        screen.draw((' ' if max_title_length == 5 else '') + '…' + (' ' if max_title_length >= 4 else ''))
+        draw_sep(right_sep)
+    else:
+        draw_sep(left_sep)
+        screen.draw(' ')
+        draw_title(draw_data, screen, tab, index)
+        extra = screen.cursor.x - before - max_title_length
+        if extra >= 0:
+            screen.cursor.x -= extra + 3
+            screen.draw('…')
+        elif extra == -1:
+            screen.cursor.x -= 2
+            screen.draw('…')
+        screen.draw(' ')
+        draw_sep(right_sep)
+
+    return screen.cursor.x
+
+
 def draw_tab_with_separator(draw_data: DrawData, screen: Screen, tab: TabBarData, before: int, max_title_length: int, index: int, is_last: bool) -> 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))
@@ -332,12 +371,15 @@ class TabBar:
             opts.tab_bar_background or opts.background, opts.tab_title_template,
             opts.active_tab_title_template,
             opts.tab_activity_symbol,
-            opts.tab_powerline_style
+            opts.tab_powerline_style,
+            'top' if opts.tab_bar_edge == 1 else 'bottom'
         )
         if opts.tab_bar_style == 'separator':
             self.draw_func = draw_tab_with_separator
         elif opts.tab_bar_style == 'powerline':
             self.draw_func = draw_tab_with_powerline
+        elif opts.tab_bar_style == 'slant':
+            self.draw_func = draw_tab_with_slant
         else:
             self.draw_func = draw_tab_with_fade