375 lines
12 KiB
Python
375 lines
12 KiB
Python
"""
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Collection of style transformations.
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Think of it as a kind of color post processing after the rendering is done.
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This could be used for instance to change the contrast/saturation; swap light
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and dark colors or even change certain colors for other colors.
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When the UI is rendered, these transformations can be applied right after the
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style strings are turned into `Attrs` objects that represent the actual
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formatting.
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"""
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from abc import ABCMeta, abstractmethod
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from colorsys import hls_to_rgb, rgb_to_hls
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from typing import Callable, Hashable, Optional, Sequence, Tuple, Union
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from prompt_toolkit.cache import memoized
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from prompt_toolkit.filters import FilterOrBool, to_filter
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from prompt_toolkit.utils import AnyFloat, to_float, to_str
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from .base import ANSI_COLOR_NAMES, Attrs
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from .style import parse_color
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__all__ = [
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"StyleTransformation",
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"SwapLightAndDarkStyleTransformation",
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"ReverseStyleTransformation",
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"SetDefaultColorStyleTransformation",
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"AdjustBrightnessStyleTransformation",
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"DummyStyleTransformation",
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"ConditionalStyleTransformation",
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"DynamicStyleTransformation",
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"merge_style_transformations",
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]
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class StyleTransformation(metaclass=ABCMeta):
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"""
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Base class for any style transformation.
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"""
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@abstractmethod
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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"""
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Take an `Attrs` object and return a new `Attrs` object.
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Remember that the color formats can be either "ansi..." or a 6 digit
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lowercase hexadecimal color (without '#' prefix).
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"""
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def invalidation_hash(self) -> Hashable:
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"""
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When this changes, the cache should be invalidated.
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"""
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return "%s-%s" % (self.__class__.__name__, id(self))
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class SwapLightAndDarkStyleTransformation(StyleTransformation):
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"""
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Turn dark colors into light colors and the other way around.
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This is meant to make color schemes that work on a dark background usable
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on a light background (and the other way around).
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Notice that this doesn't swap foreground and background like "reverse"
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does. It turns light green into dark green and the other way around.
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Foreground and background colors are considered individually.
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Also notice that when <reverse> is used somewhere and no colors are given
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in particular (like what is the default for the bottom toolbar), then this
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doesn't change anything. This is what makes sense, because when the
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'default' color is chosen, it's what works best for the terminal, and
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reverse works good with that.
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"""
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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"""
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Return the `Attrs` used when opposite luminosity should be used.
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"""
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# Reverse colors.
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attrs = attrs._replace(color=get_opposite_color(attrs.color))
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attrs = attrs._replace(bgcolor=get_opposite_color(attrs.bgcolor))
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return attrs
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class ReverseStyleTransformation(StyleTransformation):
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"""
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Swap the 'reverse' attribute.
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(This is still experimental.)
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"""
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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return attrs._replace(reverse=not attrs.reverse)
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class SetDefaultColorStyleTransformation(StyleTransformation):
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"""
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Set default foreground/background color for output that doesn't specify
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anything. This is useful for overriding the terminal default colors.
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:param fg: Color string or callable that returns a color string for the
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foreground.
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:param bg: Like `fg`, but for the background.
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"""
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def __init__(
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self, fg: Union[str, Callable[[], str]], bg: Union[str, Callable[[], str]]
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) -> None:
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self.fg = fg
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self.bg = bg
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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if attrs.bgcolor in ("", "default"):
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attrs = attrs._replace(bgcolor=parse_color(to_str(self.bg)))
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if attrs.color in ("", "default"):
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attrs = attrs._replace(color=parse_color(to_str(self.fg)))
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return attrs
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def invalidation_hash(self) -> Hashable:
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return (
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"set-default-color",
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to_str(self.fg),
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to_str(self.bg),
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)
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class AdjustBrightnessStyleTransformation(StyleTransformation):
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"""
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Adjust the brightness to improve the rendering on either dark or light
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backgrounds.
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For dark backgrounds, it's best to increase `min_brightness`. For light
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backgrounds it's best to decrease `max_brightness`. Usually, only one
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setting is adjusted.
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This will only change the brightness for text that has a foreground color
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defined, but no background color. It works best for 256 or true color
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output.
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.. note:: Notice that there is no universal way to detect whether the
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application is running in a light or dark terminal. As a
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developer of an command line application, you'll have to make
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this configurable for the user.
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:param min_brightness: Float between 0.0 and 1.0 or a callable that returns
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a float.
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:param max_brightness: Float between 0.0 and 1.0 or a callable that returns
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a float.
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"""
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def __init__(
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self, min_brightness: AnyFloat = 0.0, max_brightness: AnyFloat = 1.0
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) -> None:
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self.min_brightness = min_brightness
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self.max_brightness = max_brightness
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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min_brightness = to_float(self.min_brightness)
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max_brightness = to_float(self.max_brightness)
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assert 0 <= min_brightness <= 1
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assert 0 <= max_brightness <= 1
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# Don't do anything if the whole brightness range is acceptable.
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# This also avoids turning ansi colors into RGB sequences.
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if min_brightness == 0.0 and max_brightness == 1.0:
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return attrs
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# If a foreground color is given without a background color.
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no_background = not attrs.bgcolor or attrs.bgcolor == "default"
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has_fgcolor = attrs.color and attrs.color != "ansidefault"
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if has_fgcolor and no_background:
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# Calculate new RGB values.
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r, g, b = self._color_to_rgb(attrs.color or "")
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hue, brightness, saturation = rgb_to_hls(r, g, b)
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brightness = self._interpolate_brightness(
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brightness, min_brightness, max_brightness
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)
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r, g, b = hls_to_rgb(hue, brightness, saturation)
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new_color = "%02x%02x%02x" % (int(r * 255), int(g * 255), int(b * 255))
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attrs = attrs._replace(color=new_color)
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return attrs
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def _color_to_rgb(self, color: str) -> Tuple[float, float, float]:
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"""
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Parse `style.Attrs` color into RGB tuple.
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"""
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# Do RGB lookup for ANSI colors.
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try:
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from prompt_toolkit.output.vt100 import ANSI_COLORS_TO_RGB
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r, g, b = ANSI_COLORS_TO_RGB[color]
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return r / 255.0, g / 255.0, b / 255.0
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except KeyError:
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pass
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# Parse RRGGBB format.
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return (
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int(color[0:2], 16) / 255.0,
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int(color[2:4], 16) / 255.0,
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int(color[4:6], 16) / 255.0,
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)
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# NOTE: we don't have to support named colors here. They are already
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# transformed into RGB values in `style.parse_color`.
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def _interpolate_brightness(
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self, value: float, min_brightness: float, max_brightness: float
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) -> float:
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"""
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Map the brightness to the (min_brightness..max_brightness) range.
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"""
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return min_brightness + (max_brightness - min_brightness) * value
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def invalidation_hash(self) -> Hashable:
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return (
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"adjust-brightness",
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to_float(self.min_brightness),
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to_float(self.max_brightness),
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)
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class DummyStyleTransformation(StyleTransformation):
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"""
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Don't transform anything at all.
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"""
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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return attrs
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def invalidation_hash(self) -> Hashable:
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# Always return the same hash for these dummy instances.
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return "dummy-style-transformation"
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class DynamicStyleTransformation(StyleTransformation):
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"""
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StyleTransformation class that can dynamically returns any
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`StyleTransformation`.
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:param get_style_transformation: Callable that returns a
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:class:`.StyleTransformation` instance.
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"""
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def __init__(
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self, get_style_transformation: Callable[[], Optional[StyleTransformation]]
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) -> None:
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self.get_style_transformation = get_style_transformation
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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style_transformation = (
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self.get_style_transformation() or DummyStyleTransformation()
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)
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return style_transformation.transform_attrs(attrs)
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def invalidation_hash(self) -> Hashable:
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style_transformation = (
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self.get_style_transformation() or DummyStyleTransformation()
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)
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return style_transformation.invalidation_hash()
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class ConditionalStyleTransformation(StyleTransformation):
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"""
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Apply the style transformation depending on a condition.
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"""
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def __init__(
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self, style_transformation: StyleTransformation, filter: FilterOrBool
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) -> None:
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self.style_transformation = style_transformation
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self.filter = to_filter(filter)
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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if self.filter():
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return self.style_transformation.transform_attrs(attrs)
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return attrs
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def invalidation_hash(self) -> Hashable:
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return (self.filter(), self.style_transformation.invalidation_hash())
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class _MergedStyleTransformation(StyleTransformation):
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def __init__(self, style_transformations: Sequence[StyleTransformation]) -> None:
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self.style_transformations = style_transformations
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def transform_attrs(self, attrs: Attrs) -> Attrs:
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for transformation in self.style_transformations:
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attrs = transformation.transform_attrs(attrs)
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return attrs
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def invalidation_hash(self) -> Hashable:
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return tuple(t.invalidation_hash() for t in self.style_transformations)
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def merge_style_transformations(
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style_transformations: Sequence[StyleTransformation],
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) -> StyleTransformation:
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"""
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Merge multiple transformations together.
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"""
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return _MergedStyleTransformation(style_transformations)
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# Dictionary that maps ANSI color names to their opposite. This is useful for
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# turning color schemes that are optimized for a black background usable for a
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# white background.
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OPPOSITE_ANSI_COLOR_NAMES = {
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"ansidefault": "ansidefault",
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"ansiblack": "ansiwhite",
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"ansired": "ansibrightred",
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"ansigreen": "ansibrightgreen",
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"ansiyellow": "ansibrightyellow",
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"ansiblue": "ansibrightblue",
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"ansimagenta": "ansibrightmagenta",
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"ansicyan": "ansibrightcyan",
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"ansigray": "ansibrightblack",
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"ansiwhite": "ansiblack",
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"ansibrightred": "ansired",
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"ansibrightgreen": "ansigreen",
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"ansibrightyellow": "ansiyellow",
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"ansibrightblue": "ansiblue",
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"ansibrightmagenta": "ansimagenta",
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"ansibrightcyan": "ansicyan",
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"ansibrightblack": "ansigray",
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}
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assert set(OPPOSITE_ANSI_COLOR_NAMES.keys()) == set(ANSI_COLOR_NAMES)
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assert set(OPPOSITE_ANSI_COLOR_NAMES.values()) == set(ANSI_COLOR_NAMES)
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@memoized()
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def get_opposite_color(colorname: Optional[str]) -> Optional[str]:
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"""
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Take a color name in either 'ansi...' format or 6 digit RGB, return the
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color of opposite luminosity (same hue/saturation).
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This is used for turning color schemes that work on a light background
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usable on a dark background.
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"""
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if colorname is None: # Because color/bgcolor can be None in `Attrs`.
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return None
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# Special values.
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if colorname in ("", "default"):
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return colorname
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# Try ANSI color names.
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try:
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return OPPOSITE_ANSI_COLOR_NAMES[colorname]
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except KeyError:
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# Try 6 digit RGB colors.
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r = int(colorname[:2], 16) / 255.0
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g = int(colorname[2:4], 16) / 255.0
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b = int(colorname[4:6], 16) / 255.0
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h, l, s = rgb_to_hls(r, g, b)
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l = 1 - l
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r, g, b = hls_to_rgb(h, l, s)
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r = int(r * 255)
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g = int(g * 255)
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b = int(b * 255)
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return "%02x%02x%02x" % (r, g, b)
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