# `Offlixir.Easter`
[🔗](https://github.com/F0lamie/Offlixir/blob/v0.1.0/lib/offlixir/easter.ex#L1)

Easter Sunday in the Gregorian (Catholic and Protestant) and Orthodox traditions.

# `gregorian`

```elixir
@spec gregorian(integer()) :: Date.t()
```

Returns Easter Sunday of `year` in the Gregorian computus.

    iex> Offlixir.Easter.gregorian(2026)
    ~D[2026-04-05]

# `gregorian_shift`

```elixir
@spec gregorian_shift(integer()) :: integer()
```

Returns the number of days added to a Julian calendar date of `year` to get the
Gregorian calendar date.

The gap is valid for a date from the 1st of March of `year` to the end of
February of the next year, which always holds for Easter. Before 1583 the
Gregorian date is proleptic. The gap is negative before the year 200.

    iex> Offlixir.Easter.gregorian_shift(2026)
    13

# `orthodox`

```elixir
@spec orthodox(integer()) :: Date.t()
```

Returns Orthodox Easter Sunday of `year` as a Gregorian calendar date.

The date is computed in the Julian calendar, then shifted by the gap between the
two calendars (see `gregorian_shift/1`).

    iex> Offlixir.Easter.orthodox(2026)
    ~D[2026-04-12]

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*Consult [api-reference.md](api-reference.md) for complete listing*