diff kitten: New option to control the background color for filler lines in the margin

Fixes #2518

Author: kovidgoyal

docs/changelog.rst

@@ -19,6 +19,9 @@ To update |kitty|, :doc:`follow the instructions <binary>`.
 - Render known country flags designated by a pair of unicode codepoints
   in two cells instead of four.
 
+- diff kitten: New option to control the background color for filler lines in
+  the margin (:iss:`2518`)
+
 
 0.17.2 [2020-03-29]
 --------------------

kittens/diff/config.py

@@ -19,7 +19,7 @@
 
 defaults: Optional[DiffOptions] = None
 
-formats = {
+formats: Dict[str, str] = {
     'title': '',
     'margin': '',
     'text': '',
@@ -35,6 +35,7 @@ def set_formats(opts: DiffOptions) -> None:
     formats['added'] = '48' + color_as_sgr(opts.added_bg)
     formats['removed'] = '48' + color_as_sgr(opts.removed_bg)
     formats['filler'] = '48' + color_as_sgr(opts.filler_bg)
+    formats['margin_filler'] = '48' + color_as_sgr(opts.margin_filler_bg or opts.filler_bg)
     formats['hunk_margin'] = '38' + color_as_sgr(opts.margin_fg) + ';48' + color_as_sgr(opts.hunk_margin_bg)
     formats['hunk'] = '38' + color_as_sgr(opts.margin_fg) + ';48' + color_as_sgr(opts.hunk_bg)
     formats['removed_highlight'] = '48' + color_as_sgr(opts.highlight_removed_bg)

kittens/diff/config_data.py

@@ -9,7 +9,9 @@
 from typing import Any, Dict, Sequence, Union
 
 from kitty.conf.definition import Option, Shortcut, option_func
-from kitty.conf.utils import positive_int, python_string, to_color
+from kitty.conf.utils import (
+    positive_int, python_string, to_color, to_color_or_none
+)
 
 # }}}
 
@@ -78,6 +80,8 @@ def syntax_aliases(raw: str) -> Dict[str, str]:
 c('added_margin_bg', '#cdffd8')
 
 c('filler_bg', '#fafbfc', long_text=_('Filler (empty) line background'))
+c('margin_filler_bg', 'none', option_type=to_color_or_none, long_text=_(
+    'Filler (empty) line background in margins, defaults to the filler background'))
 
 c('hunk_margin_bg', '#dbedff', long_text=_('Hunk header colors'))
 c('hunk_bg', '#f1f8ff')

kittens/diff/render.py

@@ -141,6 +141,7 @@ def formatted(text: str) -> str:
 removed_margin_format = format_func('removed_margin')
 added_margin_format = format_func('added_margin')
 filler_format = format_func('filler')
+margin_filler_format = format_func('margin_filler')
 hunk_margin_format = format_func('hunk_margin')
 hunk_format = format_func('hunk')
 highlight_map = {'remove': ('removed_highlight', 'removed'), 'add': ('added_highlight', 'added')}
@@ -214,7 +215,7 @@ def split_with_highlights(line: str, width: int, highlights: List, bg_highlight:
     return _split_with_highlights(line, truncate_pts, highlights, bg_highlight)
 
 
-margin_bg_map = {'filler': filler_format, 'remove': removed_margin_format, 'add': added_margin_format, 'context': margin_format}
+margin_bg_map = {'filler': margin_filler_format, 'remove': removed_margin_format, 'add': added_margin_format, 'context': margin_format}
 text_bg_map = {'filler': filler_format, 'remove': removed_format, 'add': added_format, 'context': text_format}