pyansistring

pyansistring gives you a string type that keeps styling securely attached while you use familiar, native Python string operations. Whether you are building a simple CLI tool, visualizing data in a complex terminal dashboard, or exporting styled output to the web, pyansistring handles the math and formatting for you.

Features

• ANSIString class that subclasses Python str.
• Style-preserving operations for concatenation, slicing, splitting, joining, replacing, stripping, case transforms, and formatting (f-strings, .format()).
• SGR styling and attributes: bold, dim, italic, underline, strikethrough, invert, and advanced underline modes (single, double, curly, dotted, dashed).
• Color channels: 4-bit ANSI, 8-bit palette, and 24-bit RGB for foreground, background, and underlines.
• Targeting modes: apply to full strings, slice ranges, or word matches (case-sensitive or insensitive).
• Gradient engine: RGB or HSL interpolation, coordinate-based gradients for multiline text, and out-of-bounds handling.
• SVG export: render text or path modes with per-character coloring and optional custom fonts.
• ANSI parsing: convert raw ANSI-encoded strings back into ANSIString instances with styles intact.
• Large constants base: extensive predefined color constants and palettes, plus SGR/regex helpers for easy access.

Requirements

• Python 3.11+

Installation

Install the base package:

pip install pyansistring

Install extras when needed:

pip install pyansistring[svg]            # For SVG export
pip install pyansistring[all]            # Install all optional dependencies

Quick Start

from pyansistring import ANSIString, Foreground, Background, SGR

text = (
    ANSIString("Hello, World!")
    .fg_4b(Foreground.YELLOW)
    .bg_4b(Background.BLUE)
    .style(SGR.BOLD)
)

print(text)

Usage Examples

The examples below are generated by examples/generate_usage_svg.py.

Unstyled text

from pyansistring import ANSIString

print(ANSIString("Hello, World!"))

Whole-string styling

from pyansistring import ANSIString, Foreground, Background, SGR

print(
    ANSIString("Hello, World!")
    .fg_4b(Foreground.YELLOW)
    .bg_4b(Background.BLUE)
    .style(SGR.BOLD)
)

Style by slice

from pyansistring import ANSIString, Foreground, Background, SGR

print(
    ANSIString("Hello, World!")
    .fg_4b(Foreground.YELLOW, (0, 5), (7, 12))
    .bg_4b(Background.BLUE, (7, 12))
    .style(SGR.BOLD, (7, 12))
)

Style by words

from pyansistring import ANSIString, Foreground, Background, SGR

print(
    ANSIString("Hello, World!")
    .fg_4b_words(Foreground.YELLOW, "Hello", "World")
    .bg_4b_words(Background.BLUE, "World")
    .style_words(SGR.BOLD, "Hello", "World")
)

SGR attributes

from pyansistring import ANSIString, SGR

print(ANSIString("Hello, World!").style(SGR.BOLD).style(SGR.UNDERLINE))

4-bit, 8-bit, and 24-bit colors

from pyansistring import ANSIString, Foreground, Background

print(ANSIString("Hello, World!").fg_4b(Foreground.YELLOW).bg_4b(Background.BLUE))
print(ANSIString("Hello, World!").fg_8b(11).bg_8b(4).ul_8b(74))
print(ANSIString("Hello, World!").fg_24b(255, 255, 0).bg_24b(0, 0, 238).ul_24b(135, 175, 215))

Underline modes

from pyansistring import ANSIString, UnderlineMode

print(
    ANSIString("Hello, World!")
    .bg_24b(255, 255, 255)
    .ul_24b(255, 0, 0)
    .style(UnderlineMode.DOUBLE)
)

Rainbow

from pyansistring import ANSIString

print(ANSIString("Hello, World! This is rainbow text!").rainbow(fg=True))

Gradient APIs

from pyansistring import ANSIString

print(
    ANSIString("Hello, World! This is gradient text!")
    .gradient([(84, 161, 255), (233, 200, 216)], fg=True)
)

print(
    ANSIString("Hello, colorful gradient world!")
    .gradient_words([(255, 99, 71), (255, 215, 0)], "Hello", "world", case_sensitive=False, fg=True)
)

print(
    ANSIString("HELLO\nworld")
    .gradient_coordinates(
        [(255, 0, 120), (0, 200, 255)],
        (1, 1),
        (2, 1),
        (3, 1),
        (4, 1),
        (5, 1),
        index_base=1,
        fg=True,
    )
)

Parse ANSI text back into ANSIString

from pyansistring import ANSIString

raw = "\x1b[31mError\x1b[0m: file not found"
parsed = ANSIString.from_ansi(raw)

print(parsed.plain_text)
print(parsed)

Export ANSIString to SVG

from fontTools.ttLib import TTFont
from pyansistring import ANSIString, SGR

font = TTFont("path/to/font.ttf")
styled = ANSIString("SVG output").style(SGR.BOLD).fg_24b(90, 170, 255)

svg_code = styled.to_svg(
    font=font,
    font_size_px=16,
    convert_text_to_path=False,
)

For a complete terminal tour, run examples/showcase.py.

Contributing

Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feat/amazing-feature)
3. Commit your Changes (git commit -m 'feat: ✨ add some amazing-feature')
4. Push to the Branch (git push origin feat/amazing-feature)
5. Open a Pull Request

Important

If linting or tests fail, make sure to fix those and push the changes.

License

Distributed under the MIT License. See LICENSE for more information.