Pngex.set_depth

You're seeing just the function set_depth, go back to Pngex module for more information.
Link to this function

set_depth(pngex, depth)

Specs

set_depth(t(), bit_depth()) :: t() | {:error, [{:invalid_depth, any()}]}

Sets bit depth.

Examples

iex> Pngex.new() |> Pngex.set_depth(:depth16)
%Pngex{depth: :depth16}
iex> Pngex.new() |> Pngex.set_depth(:depth15)
{:error, invalid_depth: :depth15}