48 lines
1.2 KiB
Elixir
48 lines
1.2 KiB
Elixir
defimpl Vivid.PNG, for: Vivid.Buffer do
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alias Vivid.{Buffer, RGBA}
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@moduledoc """
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Convert a Vivid buffer to a PNG file.
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"""
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@doc """
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Convert a Vivid buffer into a PNG file.
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"""
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@spec to_png(Buffer.t(), Path.t()) :: :ok | {:error, any}
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def to_png(buffer, path) do
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with {:ok, file} <- File.open(path, [:write]),
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png <- create_png(buffer, file),
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:ok <- :png.close(png),
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do: File.close(file)
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end
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defp config(%Buffer{rows: height, columns: width}, file) do
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%{
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size: {width, height},
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mode: {:rgba, 8},
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file: file
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}
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end
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defp create_png(%Buffer{columns: width} = buffer, file) do
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png =
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buffer
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|> config(file)
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|> :png.create()
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buffer
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|> Stream.map(&colour_to_binary(&1))
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|> Stream.chunk(width)
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|> Stream.map(&Enum.join(&1))
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|> Enum.reverse()
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|> Enum.reduce(png, &:png.append(&2, {:row, &1}))
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end
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defp colour_to_binary(%RGBA{red: r, green: g, blue: b, alpha: a}) do
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r = round(r * 255)
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g = round(g * 255)
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b = round(b * 255)
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a = round(a * 255)
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<<r::integer-size(8), g::integer-size(8), b::integer-size(8), a::integer-size(8)>>
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end
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end
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