From 658d7c69add4421058c6b64c84b6f21ca7ea0e87 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Sun, 22 Mar 2026 17:50:56 -0700
Subject: [PATCH 1/8] Add default_colors API to Theme DSL for setting terminal
 fg/bg

Themes can now declare default foreground/background colors via
t.default_colors(foreground:, background:) which calls
Curses.assume_default_colors during activation. Themes without
default_colors reset to terminal defaults (-1, -1).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 lib/textbringer/theme.rb             | 32 +++++++++++++++++
 lib/textbringer/themes/catppuccin.rb |  2 ++
 lib/textbringer/themes/github.rb     |  2 ++
 lib/textbringer/themes/gruvbox.rb    |  2 ++
 lib/textbringer/themes/sonokai.rb    |  2 ++
 test/textbringer/test_theme.rb       | 54 ++++++++++++++++++++++++++++
 6 files changed, 94 insertions(+)

diff --git a/lib/textbringer/theme.rb b/lib/textbringer/theme.rb
index dcadbfd7..e8683a9a 100644
--- a/lib/textbringer/theme.rb
+++ b/lib/textbringer/theme.rb
@@ -73,6 +73,7 @@ def initialize(name)
       @name = name
       @palettes = {}
       @face_definitions = []
+      @default_colors = nil
     end
 
     attr_reader :name
@@ -87,6 +88,10 @@ def face(name, **attrs)
       @face_definitions << [name, attrs]
     end
 
+    def default_colors(foreground:, background:)
+      @default_colors = { foreground: foreground, background: background }
+    end
+
     def activate
       mode = self.class.background_mode
       tier = self.class.color_tier
@@ -113,6 +118,33 @@ def activate
         Face.define(face_name, **resolved)
       end
       @@current = self
+      apply_default_colors(palette, tier)
+    end
+
+    private
+
+    def apply_default_colors(palette, tier)
+      if @default_colors
+        fg = resolve_default_color(@default_colors[:foreground], palette, tier)
+        bg = resolve_default_color(@default_colors[:background], palette, tier)
+      else
+        fg = "default"
+        bg = "default"
+      end
+      Curses.assume_default_colors(Color[fg], Color[bg])
+    end
+
+    def resolve_default_color(val, palette, tier)
+      if val.is_a?(Symbol)
+        color = palette.resolve(val, tier)
+        unless color
+          raise EditorError,
+                "Unknown palette color :#{val} for default_colors"
+        end
+        color
+      else
+        val || "default"
+      end
     end
 
     private_class_method def self.detect_background_via_osc11
diff --git a/lib/textbringer/themes/catppuccin.rb b/lib/textbringer/themes/catppuccin.rb
index b7167fa1..a7a54c08 100644
--- a/lib/textbringer/themes/catppuccin.rb
+++ b/lib/textbringer/themes/catppuccin.rb
@@ -68,6 +68,8 @@
     p.color :rosewater, hex: "#d78787", ansi: "red"
   end
 
+  t.default_colors foreground: :text, background: :base
+
   # Programming faces (from catppuccin/nvim syntax.lua)
   t.face :comment,                foreground: :overlay2
   t.face :preprocessing_directive, foreground: :pink
diff --git a/lib/textbringer/themes/github.rb b/lib/textbringer/themes/github.rb
index a3c481c0..cd6db30e 100644
--- a/lib/textbringer/themes/github.rb
+++ b/lib/textbringer/themes/github.rb
@@ -48,6 +48,8 @@
     p.color :darkblue, hex: "#c1daec", ansi: "blue"         # dcolors.darkblue = blue1
   end
 
+  t.default_colors foreground: :fg, background: :bg
+
   # Programming faces
   t.face :comment,                  foreground: :comment   # Comment = base2
   t.face :preprocessing_directive,  foreground: :red       # PreProc = red
diff --git a/lib/textbringer/themes/gruvbox.rb b/lib/textbringer/themes/gruvbox.rb
index 86b3285a..12f9c7f6 100644
--- a/lib/textbringer/themes/gruvbox.rb
+++ b/lib/textbringer/themes/gruvbox.rb
@@ -47,6 +47,8 @@
     p.color :orange, hex: "#d75f00", ansi: "red"
   end
 
+  t.default_colors foreground: :fg1, background: :bg0
+
   # Programming faces
   t.face :comment,                foreground: :gray
   t.face :preprocessing_directive, foreground: :aqua
diff --git a/lib/textbringer/themes/sonokai.rb b/lib/textbringer/themes/sonokai.rb
index 0940556d..7a383581 100644
--- a/lib/textbringer/themes/sonokai.rb
+++ b/lib/textbringer/themes/sonokai.rb
@@ -26,6 +26,8 @@
     p.color :purple,   hex: "#d787d7", ansi: "magenta"
   end
 
+  t.default_colors foreground: :fg, background: :bg0
+
   # Programming faces (from sonokai highlight groups)
   t.face :comment,                foreground: :grey
   t.face :preprocessing_directive, foreground: :red
diff --git a/test/textbringer/test_theme.rb b/test/textbringer/test_theme.rb
index 6f38eed3..8f7f0bf4 100644
--- a/test/textbringer/test_theme.rb
+++ b/test/textbringer/test_theme.rb
@@ -106,6 +106,60 @@ def test_activate_with_inherit
     Face.delete(:derived_kw)
   end
 
+  def test_activate_sets_default_colors
+    Theme.define "test_defcol" do |t|
+      t.palette :dark do |p|
+        p.color :fg, hex: "#ffffff", ansi: "white"
+        p.color :bg, hex: "#000000", ansi: "black"
+      end
+      t.default_colors foreground: :fg, background: :bg
+      t.face :test_defcol_face, foreground: :fg
+    end
+    Theme["test_defcol"].activate
+    fg_num = Color["#ffffff"]
+    bg_num = Color["#000000"]
+    assert_equal([fg_num, bg_num], Curses.default_colors)
+  ensure
+    Face.delete(:test_defcol_face)
+  end
+
+  def test_activate_resets_default_colors_when_not_specified
+    Theme.define "test_with_defcol" do |t|
+      t.palette :dark do |p|
+        p.color :fg, hex: "#ffffff", ansi: "white"
+        p.color :bg, hex: "#000000", ansi: "black"
+      end
+      t.default_colors foreground: :fg, background: :bg
+      t.face :test_wdc_face, foreground: :fg
+    end
+    Theme["test_with_defcol"].activate
+    assert_not_equal([-1, -1], Curses.default_colors)
+
+    Theme.define "test_no_defcol" do |t|
+      t.palette :dark do |p|
+        p.color :fg, hex: "#ffffff", ansi: "white"
+      end
+      t.face :test_ndc_face, foreground: :fg
+    end
+    Theme["test_no_defcol"].activate
+    assert_equal([-1, -1], Curses.default_colors)
+  ensure
+    Face.delete(:test_wdc_face)
+    Face.delete(:test_ndc_face)
+  end
+
+  def test_activate_default_colors_raises_on_unknown_palette
+    Theme.define "test_bad_defcol" do |t|
+      t.palette :dark do |p|
+        p.color :fg, hex: "#ffffff", ansi: "white"
+      end
+      t.default_colors foreground: :nonexistent, background: :fg
+    end
+    assert_raise(EditorError) do
+      Theme["test_bad_defcol"].activate
+    end
+  end
+
   def test_load_default_activates_faces
     face = Face[:comment]
     assert_not_nil(face)

From a998b8efa6c9a346885d41c10d021a3953078273 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Sun, 22 Mar 2026 17:57:25 -0700
Subject: [PATCH 2/8] Add default_colors to tokyonight and molokai themes

Both original themes set Normal fg/bg; our ports were missing it.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 lib/textbringer/themes/molokai.rb    | 2 ++
 lib/textbringer/themes/tokyonight.rb | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/lib/textbringer/themes/molokai.rb b/lib/textbringer/themes/molokai.rb
index 7b760668..a3c5cbcf 100644
--- a/lib/textbringer/themes/molokai.rb
+++ b/lib/textbringer/themes/molokai.rb
@@ -27,6 +27,8 @@
     p.color :search,  hex: "#ffd787", ansi: "yellow"       # 222  Search bg
   end
 
+  t.default_colors foreground: :fg, background: :bg
+
   # Programming faces
   t.face :comment,                  foreground: :comment
   t.face :preprocessing_directive,  foreground: :green
diff --git a/lib/textbringer/themes/tokyonight.rb b/lib/textbringer/themes/tokyonight.rb
index abb6ee24..26bbc5ce 100644
--- a/lib/textbringer/themes/tokyonight.rb
+++ b/lib/textbringer/themes/tokyonight.rb
@@ -29,6 +29,8 @@
     p.color :blue5,   hex: "#89ddff", ansi: "cyan"         # Operator, punctuation delimiters
   end
 
+  t.default_colors foreground: :fg, background: :bg
+
   # Programming faces
   t.face :comment,                  foreground: :comment
   t.face :preprocessing_directive,  foreground: :cyan     # PreProc = c.cyan

From b39ed6f2f216f0f8ad5f050cac1e435eae56fbe0 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Sun, 22 Mar 2026 18:07:11 -0700
Subject: [PATCH 3/8] Add set_foreground_color and set_background_color
 commands

Emacs-compatible interactive commands for changing the terminal's
default foreground or background color independently. Window now
tracks current default colors so each command can update one without
resetting the other.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 lib/textbringer/commands/windows.rb | 14 ++++++++++++++
 lib/textbringer/window.rb           |  6 +++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/textbringer/commands/windows.rb b/lib/textbringer/commands/windows.rb
index 575d341b..bc53bbe6 100644
--- a/lib/textbringer/commands/windows.rb
+++ b/lib/textbringer/commands/windows.rb
@@ -84,6 +84,20 @@ module Commands
       end
     end
 
+    define_command(:set_foreground_color, doc: <<~EOD) do
+        Set the default foreground color.
+      EOD
+      |color = read_from_minibuffer("Foreground color: ")|
+      Window.set_default_colors(color, nil)
+    end
+
+    define_command(:set_background_color, doc: <<~EOD) do
+        Set the default background color.
+      EOD
+      |color = read_from_minibuffer("Background color: ")|
+      Window.set_default_colors(nil, color)
+    end
+
     define_command(:list_buffers, doc: <<~EOD) do |buffers = Buffer.list|
         List the existing buffers.
       EOD
diff --git a/lib/textbringer/window.rb b/lib/textbringer/window.rb
index 1cdae58a..6307692e 100644
--- a/lib/textbringer/window.rb
+++ b/lib/textbringer/window.rb
@@ -33,6 +33,8 @@ class Window
     @@minibuffer_selected = nil
     @@echo_area = nil
     @@has_colors = false
+    @@default_fg = "default"
+    @@default_bg = "default"
 
     def self.list(include_echo_area: false)
       if include_echo_area
@@ -133,7 +135,9 @@ def self.colors
     end
 
     def self.set_default_colors(fg, bg)
-      Curses.assume_default_colors(Color[fg], Color[bg])
+      @@default_fg = fg if fg
+      @@default_bg = bg if bg
+      Curses.assume_default_colors(Color[@@default_fg], Color[@@default_bg])
       Window.redraw
     end
 

From 1e104510eb23da876ff3994f3b12eb374226f611 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Sun, 22 Mar 2026 18:32:07 -0700
Subject: [PATCH 4/8] Use :default face instead of color_pair 0 for base text
 rendering

Curses.assume_default_colors only affects color_pair 0 and does not
reliably update the display when called after initial setup (e.g.
to keep terminal background transparency while using theme fg).

Now set_default_colors also defines a :default face with the
resolved fg/bg colors. All fallback sites in Window that previously
used attr_set(0, 0) now use Face[:default], ensuring theme colors
are applied consistently even when one component is overridden.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 lib/textbringer/window.rb | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/textbringer/window.rb b/lib/textbringer/window.rb
index 6307692e..0c8e9a30 100644
--- a/lib/textbringer/window.rb
+++ b/lib/textbringer/window.rb
@@ -138,7 +138,9 @@ def self.set_default_colors(fg, bg)
       @@default_fg = fg if fg
       @@default_bg = bg if bg
       Curses.assume_default_colors(Color[@@default_fg], Color[@@default_bg])
-      Window.redraw
+      Face.define(:default,
+                  foreground: @@default_fg, background: @@default_bg)
+      Window.redraw if @@started
     end
 
     def self.load_faces
@@ -712,7 +714,8 @@ def redisplay_mode_line
       @mode_line.addstr(" #{line},#{column}")
       @mode_line.addstr(" (#{@buffer.mode_names.join(' ')})")
       @mode_line.addstr(" " * (columns - @mode_line.curx))
-      @mode_line.attr_set(0, 0)
+      default = Face[:default]
+      @mode_line.attr_set(default&.text_attrs || 0, default&.color_pair || 0)
       @mode_line.noutrefresh
     end
 
@@ -952,6 +955,7 @@ def get_char
     end
 
     def apply_face_attrs(win, face)
+      face ||= Face[:default]
       win.attr_set(face&.text_attrs || 0, face&.color_pair || 0)
     end
 
@@ -971,7 +975,8 @@ def apply_window_attrs(win)
         end
         win.attr_set(text_attrs, face.color_pair)
       else
-        win.attr_set(0, 0)
+        default = Face[:default]
+        win.attr_set(default&.text_attrs || 0, default&.color_pair || 0)
       end
     end
   end
@@ -1020,7 +1025,8 @@ def redisplay
           @window.addstr(@buffer.input_method_status)
         end
         @window.setpos(0, 0)
-        @window.attr_set(0, 0)
+        default = Face[:default]
+        @window.attr_set(default&.text_attrs || 0, default&.color_pair || 0)
         @in_region = false
         @in_isearch = false
         @current_hl_face = nil

From 969ac5d215701b76d88d0f18f66809fc6a9804b7 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Sun, 22 Mar 2026 18:38:34 -0700
Subject: [PATCH 5/8] Validate before caching in set_default_colors, handle
 empty input

- Resolve colors via Color[] before updating @@default_fg/@@default_bg
  so invalid input does not corrupt the cache
- Treat empty strings as nil (no-op) to handle blank minibuffer input
- Add tests for partial update (nil preserves other side) and empty
  string handling

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 lib/textbringer/window.rb       | 15 ++++++++++-----
 test/textbringer/test_window.rb | 22 ++++++++++++++++++++++
 2 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/lib/textbringer/window.rb b/lib/textbringer/window.rb
index 0c8e9a30..227b5920 100644
--- a/lib/textbringer/window.rb
+++ b/lib/textbringer/window.rb
@@ -135,11 +135,16 @@ def self.colors
     end
 
     def self.set_default_colors(fg, bg)
-      @@default_fg = fg if fg
-      @@default_bg = bg if bg
-      Curses.assume_default_colors(Color[@@default_fg], Color[@@default_bg])
-      Face.define(:default,
-                  foreground: @@default_fg, background: @@default_bg)
+      fg = nil if fg.respond_to?(:empty?) && fg.empty?
+      bg = nil if bg.respond_to?(:empty?) && bg.empty?
+      new_fg = fg || @@default_fg
+      new_bg = bg || @@default_bg
+      fg_color = Color[new_fg]
+      bg_color = Color[new_bg]
+      Curses.assume_default_colors(fg_color, bg_color)
+      @@default_fg = new_fg
+      @@default_bg = new_bg
+      Face.define(:default, foreground: new_fg, background: new_bg)
       Window.redraw if @@started
     end
 
diff --git a/test/textbringer/test_window.rb b/test/textbringer/test_window.rb
index d0c482ad..cb5b4e8b 100644
--- a/test/textbringer/test_window.rb
+++ b/test/textbringer/test_window.rb
@@ -432,6 +432,28 @@ def test_s_set_default_colors
     assert_equal([-1, -1], Curses.default_colors)
   end
 
+  def test_s_set_default_colors_partial_update
+    Window.set_default_colors("red", "blue")
+    assert_equal([1, 4], Curses.default_colors)
+
+    # Update only bg, fg should be preserved
+    Window.set_default_colors(nil, "default")
+    assert_equal([1, -1], Curses.default_colors)
+
+    # Update only fg, bg should be preserved
+    Window.set_default_colors("green", nil)
+    assert_equal([2, -1], Curses.default_colors)
+  end
+
+  def test_s_set_default_colors_empty_string_ignored
+    Window.set_default_colors("red", "blue")
+    assert_equal([1, 4], Curses.default_colors)
+
+    # Empty string should be treated as nil (no change)
+    Window.set_default_colors("", "")
+    assert_equal([1, 4], Curses.default_colors)
+  end
+
   private
 
   def window_string(window)

From 9f479d55b36bcf54ec75744713bd0a8252e18927 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Mon, 23 Mar 2026 10:44:22 +0900
Subject: [PATCH 6/8] Window.set_default_colors should be used to update
 @@default_fg/@@default_bg

---
 lib/textbringer/theme.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/textbringer/theme.rb b/lib/textbringer/theme.rb
index e8683a9a..f633d750 100644
--- a/lib/textbringer/theme.rb
+++ b/lib/textbringer/theme.rb
@@ -131,7 +131,7 @@ def apply_default_colors(palette, tier)
         fg = "default"
         bg = "default"
       end
-      Curses.assume_default_colors(Color[fg], Color[bg])
+      Window.set_default_colors(fg, bg)
     end
 
     def resolve_default_color(val, palette, tier)

From 4d159ab7a76e24bd38cc0ea3dfb39f4c6be2eeab Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Mon, 23 Mar 2026 10:44:56 +0900
Subject: [PATCH 7/8] Empty string should be treated as error

---
 lib/textbringer/window.rb       | 6 +-----
 test/textbringer/test_window.rb | 7 ++++---
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/lib/textbringer/window.rb b/lib/textbringer/window.rb
index 227b5920..35558668 100644
--- a/lib/textbringer/window.rb
+++ b/lib/textbringer/window.rb
@@ -135,13 +135,9 @@ def self.colors
     end
 
     def self.set_default_colors(fg, bg)
-      fg = nil if fg.respond_to?(:empty?) && fg.empty?
-      bg = nil if bg.respond_to?(:empty?) && bg.empty?
       new_fg = fg || @@default_fg
       new_bg = bg || @@default_bg
-      fg_color = Color[new_fg]
-      bg_color = Color[new_bg]
-      Curses.assume_default_colors(fg_color, bg_color)
+      Curses.assume_default_colors(Color[new_fg], Color[new_bg])
       @@default_fg = new_fg
       @@default_bg = new_bg
       Face.define(:default, foreground: new_fg, background: new_bg)
diff --git a/test/textbringer/test_window.rb b/test/textbringer/test_window.rb
index cb5b4e8b..188baa33 100644
--- a/test/textbringer/test_window.rb
+++ b/test/textbringer/test_window.rb
@@ -449,9 +449,10 @@ def test_s_set_default_colors_empty_string_ignored
     Window.set_default_colors("red", "blue")
     assert_equal([1, 4], Curses.default_colors)
 
-    # Empty string should be treated as nil (no change)
-    Window.set_default_colors("", "")
-    assert_equal([1, 4], Curses.default_colors)
+    # Empty string should be treated as error
+    assert_raise(EditorError) do
+      Window.set_default_colors("", "")
+    end
   end
 
   private

From 6207487c15de5e7674ec84b7d32372b04590ab80 Mon Sep 17 00:00:00 2001
From: Shugo Maeda <shugo@ruby-lang.org>
Date: Sun, 22 Mar 2026 19:01:28 -0700
Subject: [PATCH 8/8] Fix Windows test failure by using Color[] instead of
 hardcoded values

PDCurses (Windows) assigns different numbers to color constants than
ncurses (e.g. COLOR_RED=4 vs 1). Use Color["red"] etc. to resolve
platform-appropriate values in assertions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 test/textbringer/test_window.rb | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/test/textbringer/test_window.rb b/test/textbringer/test_window.rb
index 188baa33..b99f36dd 100644
--- a/test/textbringer/test_window.rb
+++ b/test/textbringer/test_window.rb
@@ -433,21 +433,26 @@ def test_s_set_default_colors
   end
 
   def test_s_set_default_colors_partial_update
+    red = Color["red"]
+    blue = Color["blue"]
+    green = Color["green"]
     Window.set_default_colors("red", "blue")
-    assert_equal([1, 4], Curses.default_colors)
+    assert_equal([red, blue], Curses.default_colors)
 
     # Update only bg, fg should be preserved
     Window.set_default_colors(nil, "default")
-    assert_equal([1, -1], Curses.default_colors)
+    assert_equal([red, -1], Curses.default_colors)
 
     # Update only fg, bg should be preserved
     Window.set_default_colors("green", nil)
-    assert_equal([2, -1], Curses.default_colors)
+    assert_equal([green, -1], Curses.default_colors)
   end
 
   def test_s_set_default_colors_empty_string_ignored
+    red = Color["red"]
+    blue = Color["blue"]
     Window.set_default_colors("red", "blue")
-    assert_equal([1, 4], Curses.default_colors)
+    assert_equal([red, blue], Curses.default_colors)
 
     # Empty string should be treated as error
     assert_raise(EditorError) do