OgEx.Renderer behaviour (og_ex v0.2.0)

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Behaviour for HTML-to-image rendering backends.

OgEx passes a complete HTML document, viewport dimensions, output format, loaded font bytes, and a map of verified image resources. A renderer must return a complete encoded response body rather than raw pixels.

Summary

Types

option()

Callbacks

render(html, list)

Converts a complete HTML document into an encoded image.

Types

option()

@type option() ::
  {:width, pos_integer()}
  | {:height, pos_integer()}
  | {:format, :png | :jpeg | :webp | :svg}
  | {:fonts, [binary()]}
  | {:images, %{optional(String.t()) => binary()}}

Callbacks

render(html, list)

@callback render(html :: binary(), [option()]) :: {:ok, binary()} | {:error, term()}

Converts a complete HTML document into an encoded image.

Implementations must return bytes in the requested output format rather than raw RGBA pixels. Expected failures return {:error, reason}.