fix(code): inherit container background and adjust line number color

[Helbronner]

Overview: What does this pull request change?

This pull request fixes an issue (#4811 ) where custom formatter_style (especially in a light theme like xcode) was previously overridden by the hardcoded dark ManimColor("#222") default fill_color. It also updates the line number color logic to dynamically respect the active Pygments style.

Fixes #4811

Motivation and Explanation: Why and how do your changes improve the library?

Previously, specifying a light formatter_style (e.g., xcode) resulted in an incorrect dark container background because of the hardcoded ManimColor("#222") default.

This pull request resolves the issue by dynamically extracting the native background_color from the active Pygments style. Additionally, line number colors are now dynamically fetched from the style context (falling back to GRAY if unspecified) to prevent invisible white text on light backgrounds.

Q&A

Q: Why is the fill_color attribute preserved instead of deleted?
A: To maintain backward compatibility. While deprecating fill_color aligns with the WYSIWYG principle (since Pygments styles should dictate the theme), removing it immediately would break existing user configurations. It is recommended to deprecate this attribute now and remove it during a future major refactor of the Code class.

Links to added or changed documentation pages

Further Information and Comments

Verification

This fix successfully resolves the issue. Below is the demonstration of the expected behavior:

Test.mp4

Test Comparison

Category	Style	Before	After
Light	xcode
Light	solarized-light
Dark	lightbulb
Dark	dracula

Test Script

Code for verifying the fix

from typing import Any

from manim import *
from pygments.styles import STYLE_MAP


class Test(Scene):
    def construct(self):

        default_background_config: dict[str, Any] = {
            "buff": 0.3,
            # "fill_color": ManimColor("#222"),  # Here
            "stroke_color": WHITE,
            "corner_radius": 0.2,
            "stroke_width": 1,
            "fill_opacity": 1,
        }

        default_paragraph_config: dict[str, Any] = {
            "font": "Monospace",
            "font_size": 24,
            "line_spacing": 0.5,
            "disable_ligatures": True,
        }

        # file: str = "code_snippets.py"
        code_snippets: str = """from collections.abc import Iterator


# This is an example
class Math:
    @staticmethod
    def fib(n: int) -> Iterator[int]:
        \"""Fibonacci series up to n.\"""
        a, b = 0, 1
        while a < n:
            yield a
            a, b = b, a + b


result = sum(Math.fib(42))
print(f"The answer is {result}")
"""

        for style in list(STYLE_MAP.keys())[:]:
            mark: str = style
            rendered_code = Code(
                # code_file=file,
                code_string=mark + "\n\n" + code_snippets,
                language="python",
                formatter_style=style,  # Here
                tab_width=4,
                add_line_numbers=True,
                line_numbers_from=1,
                background="window",
                background_config=default_background_config,
                paragraph_config=default_paragraph_config,
            )

            self.add(rendered_code)
            self.wait(2)
            self.remove(rendered_code)

Related Resources

• Pygments Styles
• Pygments Styles Docs

Reviewer Checklist

• The PR title is descriptive enough for the changelog, and the PR is labeled correctly
• If applicable: newly added non-private functions and classes have a docstring including a short summary and a PARAMETERS section
• If applicable: newly added functions and classes are tested

Thanks for your time and review!