# `Monty.Frameworks.Models.Salience.Strategies.Vocus2.OperatingLimits`
[🔗](https://github.com/d-led/ex.tbp.monty/blob/v0.1.0/packages/ex_tbp_monty_core/lib/monty/frameworks/models/salience/strategies/vocus2/operating_limits.ex#L1)

What an image has to be for an attention model to mean anything on it.

Mirrors `tbp/monty/frameworks/models/salience/strategies/vocus2/vocus2.py::OperatingLimits`,
a `Protocol` in Monty. A sigma is a *distance in pixels*, so the same sigma
means a broad blur on a small image and a tight one on a large image; limits
are how "these numbers were only ever tried on images this size" is enforced
instead of remembered.

Monty answers a `ValueError` or `None`; a behaviour cannot answer an exception,
so this answers `:ok` or `{:error, message}` and the caller decides whether to
raise (which is what Monty does unless the run suppresses runtime errors).

# `rejection`

```elixir
@type rejection() :: {:error, String.t()}
```

Why these numbers are outside the limits, in a sentence.

# `t`

```elixir
@type t() :: struct()
```

# `validate`

```elixir
@callback validate(t(), pos_integer(), float(), float()) :: :ok | rejection()
```

Whether a `sigma` pair is usable on an image whose smallest side is
`min_image_dim_size`.

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