# `Alaja.ImageRenderer.PNG`
[🔗](https://github.com/Lorenzo-SF/alaja/blob/2.1.0/lib/alaja/image_renderer/png.ex#L1)

Pure Elixir PNG decoder and generator for terminal image rendering.

## Decoder

Supports PNG (grayscale, RGB, RGBA, indexed) and resizes pixel data
to a target dimension. Non-PNG formats fall back to ImageMagick's
`convert` command (via `Trebejo.Image`).

## Generator

Produces minimal PNG binaries from raw pixel data — both RGB and
RGBA variants. Used by the Kitty and iTerm2 rendering protocols.

## Usage

    {:ok, {w, h, pixels}} = Alaja.ImageRenderer.PNG.decode("image.png")

    png_bin = Alaja.ImageRenderer.PNG.generate_rgb(pixels, 100, 100)

# `decode`

```elixir
@spec decode(String.t()) ::
  {:ok, {pos_integer(), pos_integer(), [{0..255, 0..255, 0..255}]}}
  | :not_png
  | {:error, String.t()}
```

Reads and decodes a PNG file. Returns `{:ok, {width, height, pixels}}`
where `pixels` is a flat list of `{r, g, b}` tuples, or an error tuple.

For non-PNG formats, returns `:not_png` so callers can attempt a
fallback decode via ImageMagick.

# `decode_and_resize`

```elixir
@spec decode_and_resize(String.t(), pos_integer(), pos_integer()) ::
  {:ok, [[{0..255, 0..255, 0..255}]]} | {:error, String.t()}
```

Reads, decodes, and resizes a PNG file.

When `target_h` is 0, the height is derived from the aspect ratio
(accounting for terminal cells being roughly 2:1 tall).

# `generate_rgb`

```elixir
@spec generate_rgb([[{0..255, 0..255, 0..255}]], pos_integer(), pos_integer()) ::
  binary()
```

Generates an RGB PNG binary from pixel data.

# `generate_rgba`

```elixir
@spec generate_rgba(
  [[{0..255, 0..255, 0..255, 0..255}]],
  pos_integer(),
  pos_integer()
) :: binary()
```

Generates an RGBA PNG binary from pixel data (with alpha channel).

---

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