condif2css 0.15.0rc2

Evaluate Excel conditional formatting rules and generate reusable CSS classes from openpyxl styles.

condif2css

condif2css helps translate Excel conditional formatting into reusable CSS classes.

The library is designed to work with openpyxl workbooks and is currently focused on:

• Evaluating conditional-format formulas per cell (processor.process)
• Resolving workbook/theme/indexed colors to aRGB (create_themed_css_color_resolver)
• Building deduplicated CSS rules from Cell / DifferentialStyle objects (css.py)

What It Does

1. Reads conditional-format rules from an openpyxl worksheet.
2. Evaluates each rule formula against each target cell (with relative/absolute ref offsets).
3. Returns matching (sheet, cell, priority, dxf_id, stop_if_true) metadata.
4. Converts style objects into CSS declarations and stable class names.

Installation

Install from PyPI:

pip install condif2css

If the latest published version is a pre-release, use:

pip install --pre condif2css

Local development install:

pip install -e .

Or with pdm (including dev dependencies):

pdm sync --group dev

Or with uv (including dev dependencies):

uv sync --group dev

Quick Example

from openpyxl import load_workbook

from condif2css import (
    CssBuilder,
    CssRulesRegistry,
    argb_to_css,
    create_get_css_from_cell,
    create_themed_css_color_resolver,
    get_differential_style,
    get_theme_colors,
    process_conditional_formatting,
)

wb = load_workbook("input.xlsx", data_only=True)
ws = wb["Sheet1"]

theme_colors = get_theme_colors(wb)
get_argb = create_themed_css_color_resolver(theme_colors)

def get_css_color(color):
    argb = get_argb(color)
    return argb_to_css(argb) if isinstance(argb, str) else None

css_builder = CssBuilder(get_css_color)
css_registry = CssRulesRegistry(prefix="cf")
get_css_from_cell = create_get_css_from_cell(css_registry, css_builder)

# { "Sheet1\\!A1": ("Sheet1", "A1", priority, dxf_id, stop_if_true), ... }
matched_rules = process_conditional_formatting(ws)

# Apply each matched differential style and collect class names per cell
cell_classes = {}
for code, (_, _, _, dxf_id, _) in matched_rules.items():
    dxf = get_differential_style(wb, dxf_id)
    if dxf is None:
        continue
    cell_classes[code] = sorted(get_css_from_cell(dxf, is_important=True))

# Final CSS text
css_text = "\n".join(css_registry.get_rules())

Public API (Current)

• condif2css.create_themed_css_color_resolver(theme_colors)
• condif2css.get_theme_colors(workbook, strict=False)
• condif2css.process_conditional_formatting(sheet, fail_ok=True)
• condif2css.get_differential_style(workbook, dxf_id)
• condif2css.ThemeColorsError
• condif2css.CssBuilder
• condif2css.CssRulesRegistry
• condif2css.create_get_css_from_cell(...)
• condif2css.color.argb_to_css(...) and color/tint utility helpers

Current Scope and Limitations

• Conditional-format evaluation supports:
  • expression rules with exactly one formula
  • cellIs rules (equal, notEqual, greaterThan, greaterThanOrEqual, lessThan, lessThanOrEqual, between, notBetween)
  • containsText, notContainsText, beginsWith, and endsWith
• Formula evaluation expects references that resolve to single cells.
• Non-boolean formula results are ignored.
• Other conditional formatting rule types are currently skipped with a warning.
• Style extraction supports:
  • Borders: top/right/bottom/left
  • Alignment: horizontal/vertical
  • Fill: solid fills and approximated pattern fills
  • Font: size, color, bold, italic, underline
• The package provides building blocks; no CLI is included.

Development

Run tests:

pdm run pytest

Build and check distributions:

pdm build
python -m pip install --upgrade twine
python -m twine check dist/*

Releases

• Versioning is SCM-driven from Git tags.
• Stable releases must use SemVer tags in the format vMAJOR.MINOR.PATCH (example: v1.4.0).
• GitHub Actions is configured to publish on matching v* tags and validates the strict stable SemVer format before publishing.

Acknowledgements

• Theme color extraction is based on public-domain work by Mike-honey: https://gist.github.com/Mike-Honey/b36e651e9a7f1d2e1d60ce1c63b9b633

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE_APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE_MIT or https://opensource.org/licenses/MIT)

at your option.