ycal

Tool for generating printable yearly calendars.

🤖️ The code in this repo was written using Claude Code (with human oversight) 🤖

Usage

ycal can be used in two ways: through a web UI and from the terminal using a CLI.

Web UI

To use the web UI, run:

just serve

This starts a local web server and automatically opens the web UI in your default browser.

CLI

The CLI can be used to generate a self-contained HTML file that can be manually printed.

$ just gen --help

Generate a printable yearly calendar as HTML

Usage: cli [OPTIONS] --theme <THEME> <YEAR>

Arguments:
  <YEAR>  Year to generate calendar for (1-9999)

Options:
      --locale <LOCALE>
          Locale code (e.g. en-GB, sv-SE, de-DE) [default: en-GB]
      --day-name-characters <DAY_NAME_CHARACTERS>
          Number of characters to use for day names [default: 1]
      --special-days <SPECIAL_DAYS>
          Path to JSON special days file
      --theme <THEME>
          Path to CSS theme file
  -h, --help
          Print help

Examples:

# Default settings
just gen 2026 > calendar.html

# Swedish calendar with retro theme, special days and using three characters for day names
just gen 2026 --locale sv-SE --day-name-characters 3 --special-days swedish_holidays_2026.json --theme themes/retro.css > calendar.html

Special days

The --special-days option expects the file to have the following format:

[
  { "date": "2026-07-07", "name": "Dad's birthday", "is_holiday": false },
  { "date": "2026-12-24", "name": "Christmas", "is_holiday": true }
]

Days with "is_holiday": true are styled in red like weekends, while false displays the name without any color change.

You can generate a special days file with public holidays using the bundled holidays script, which uses the Nager.Date API:

just holidays 2026 GB > holidays.json
just gen 2026 --locale en-GB --theme themes/minimalist.css --special-days holidays.json > calendar.html

You can also easily use Claude Code to generate a special days file with public holidays from an arbitrary website. For example, to create one with England's bank holidays:

claude -p "Fetch https://www.gov.uk/bank-holidays and extract the England bank holidays for 2026. Output a JSON array where each entry has \"date\" (YYYY-MM-DD), \"name\", and \"is_holiday\": true. Output only the JSON." > bank-holidays.json

Architecture

The main logic for generating the calendar lives in the src/html_gen.rs library. This library uses chrono to generate calendar data and renders it using ramhorns into a self-contained HTML string.

Two frontends use this shared library:

• CLI (src/cli.rs) — Parses command-line arguments and writes the library output to stdout.
• Web UI (static/ + src/wasm.rs) — A static web page that uses a WASM build of the library. The web UI fetches public holidays directly from the Nager.Date API.

Theming is provided using separate CSS files. The theme CSS is embedded directly into the generated HTML, making the output fully self-contained.

Development

# Web UI. Builds the code and starts a live-reloading web server that hosts the files.
just dev-web

# CLI. This uses the CLI to generate HTML files for all themes in the out/ folder
# and starts a live-reloading web server that hosts the files.
just dev-cli