Merge pull request #5715 from Textualize/true-dim

True dim

Author: willmcgugan

CHANGELOG.md

@@ -16,6 +16,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Collapsible title now accepts str, Text, or Content https://github.com/Textualize/textual/pull/5697
 - Rich Text objects will be converted to Content in OptionList and other widgets https://github.com/Textualize/textual/pull/5712
+- Textual will always convert dim attributes to RGB by default
+
+### Added
+
+- Added `TEXTUAL_DIM_FACTOR` env var to set the opacity of the 'dim' ANSI attribute
 
 ## [3.0.1] - 2025-04-01
 

src/textual/_styles_cache.py

@@ -350,7 +350,9 @@ def post(segments: Iterable[Segment]) -> Iterable[Segment]:
                 ansi_theme = DEFAULT_TERMINAL_THEME
 
             if styles.tint.a:
-                segments = Tint.process_segments(segments, styles.tint, ansi_theme)
+                segments = Tint.process_segments(
+                    segments, styles.tint, ansi_theme, background
+                )
             if opacity != 1.0:
                 segments = _apply_opacity(segments, base_background, opacity)
             return segments

src/textual/constants.py

@@ -27,7 +27,9 @@ def _get_environ_bool(name: str) -> bool:
     return has_environ
 
 
-def _get_environ_int(name: str, default: int, minimum: int | None = None) -> int:
+def _get_environ_int(
+    name: str, default: int, minimum: int | None = None, maximum: int | None = None
+) -> int:
     """Retrieves an integer environment variable.
 
     Args:
@@ -48,6 +50,8 @@ def _get_environ_int(name: str, default: int, minimum: int | None = None) -> int
         return default
     if minimum is not None:
         return max(minimum, value)
+    if maximum is not None:
+        return min(maximum, value)
     return value
 
 
@@ -159,5 +163,10 @@ def _get_textual_animations() -> AnimationLevel:
 """
 
 SMOOTH_SCROLL: Final[bool] = _get_environ_int("TEXTUAL_SMOOTH_SCROLL", 1) == 1
-"""Should smooth scrolling be enabled? set `TEXTUAL_SMOOTH_SCROLL=0` to disable smooth
+"""Should smooth scrolling be enabled? set `TEXTUAL_SMOOTH_SCROLL=0` to disable smooth scrolling.
 """
+
+DIM_FACTOR: Final[float] = (
+    _get_environ_int("TEXTUAL_DIM_FACTOR", 66, minimum=0, maximum=100) / 100
+)
+"""Percentage to use as opacity when converting ANSI 'dim' attribute to RGB."""

src/textual/filter.py

@@ -22,6 +22,7 @@
 from rich.terminal_theme import TerminalTheme
 
 from textual.color import Color
+from textual.constants import DIM_FACTOR
 
 
 class LineFilter(ABC):
@@ -125,7 +126,9 @@ def apply(self, segments: list[Segment], background: Color) -> list[Segment]:
 
 
 @lru_cache(1024)
-def dim_color(background: RichColor, color: RichColor, factor: float) -> RichColor:
+def dim_color(
+    background: RichColor, color: RichColor, factor: float = DIM_FACTOR
+) -> RichColor:
     """Dim a color by blending towards the background
 
     Args:
@@ -227,7 +230,7 @@ def __init__(self, terminal_theme: TerminalTheme, enabled: bool = True):
         super().__init__(enabled=enabled)
 
     @lru_cache(1024)
-    def truecolor_style(self, style: Style) -> Style:
+    def truecolor_style(self, style: Style, background: RichColor) -> Style:
         """Replace system colors with truecolor equivalent.
 
         Args:
@@ -247,6 +250,10 @@ def truecolor_style(self, style: Style) -> Style:
             bgcolor = RichColor.from_rgb(
                 *bgcolor.get_truecolor(terminal_theme, foreground=False)
             )
+        # Convert dim style to RGB
+        if style.dim and color is not None:
+            color = dim_color(background, color)
+            style += NO_DIM
 
         return style + Style.from_color(color, bgcolor)
 
@@ -263,10 +270,16 @@ def apply(self, segments: list[Segment], background: Color) -> list[Segment]:
         _Segment = Segment
         truecolor_style = self.truecolor_style
 
+        background_rich_color = background.rich_color
+
         return [
             _Segment(
                 text,
-                None if style is None else truecolor_style(style),
+                (
+                    None
+                    if style is None
+                    else truecolor_style(style, background_rich_color)
+                ),
                 None,
             )
             for text, style, _ in segments

src/textual/renderables/text_opacity.py

@@ -52,14 +52,18 @@ def __init__(self, renderable: RenderableType, opacity: float = 1.0) -> None:
 
     @classmethod
     def process_segments(
-        cls, segments: Iterable[Segment], opacity: float, ansi_theme: TerminalTheme
+        cls,
+        segments: Iterable[Segment],
+        opacity: float,
+        ansi_theme: TerminalTheme,
     ) -> Iterable[Segment]:
         """Apply opacity to segments.
 
         Args:
             segments: Incoming segments.
             opacity: Opacity to apply.
             ansi_theme: Terminal theme.
+            background: Color of background.
 
         Returns:
             Segments with applied opacity.

src/textual/renderables/tint.py

@@ -7,7 +7,7 @@
 from rich.style import Style
 from rich.terminal_theme import TerminalTheme
 
-from textual.color import Color
+from textual.color import TRANSPARENT, Color
 from textual.filter import ANSIToTruecolor
 
 
@@ -30,14 +30,19 @@ def __init__(
 
     @classmethod
     def process_segments(
-        cls, segments: Iterable[Segment], color: Color, ansi_theme: TerminalTheme
+        cls,
+        segments: Iterable[Segment],
+        color: Color,
+        ansi_theme: TerminalTheme,
+        background: Color = TRANSPARENT,
     ) -> Iterable[Segment]:
         """Apply tint to segments.
 
         Args:
             segments: Incoming segments.
             color: Color of tint.
             ansi_theme: The TerminalTheme defining how to map ansi colors to hex.
+            background: Background color.
 
         Returns:
             Segments with applied tint.
@@ -54,7 +59,11 @@ def process_segments(
             if control:
                 yield segment
             else:
-                style = truecolor_style(style) if style is not None else NULL_STYLE
+                style = (
+                    truecolor_style(style, background)
+                    if style is not None
+                    else NULL_STYLE
+                )
                 yield _Segment(
                     text,
                     (