# `Image.Options.Compose`
[🔗](https://github.com/elixir-image/image/blob/v0.65.0/lib/image/options/compose.ex#L1)

This module processes the options for
`Image.compose/3`.

Since x,y can be relative or absolution, can be symbolic
or numeric and can even by a function this becomes more
complex that it might initially seem

# `composition_option`

```elixir
@type composition_option() ::
  {:x, non_neg_integer() | nil | :left | :center | :right}
  | {:y, non_neg_integer() | nil | :top | :middle | :bottom}
  | {:dx, integer()}
  | {:dy, integer()}
  | {:blend_mode, Image.BlendMode.t()}
  | {:x_baseline, nil | :left | :center | :right}
  | {:y_baseline, nil | :top | :middle | :bottom}
```

When composing an image on a base image, these
options drive how the composition proceeds.

* `:x` describes the absolute `x` offset on the
  base image where this image will be placed. If
  this option is set to `:left`, `:center` or
  `:right` then the `x` position will be calculated
  relative to the base image. If `:x` is nil
  (the default) then the image will be placed according
  to the relative offset of the previously composed
  image using `:dx`.

* `:y` describes the absolute `y` offset on the
  base image where this image will be placed. If
  this option is set to `:top`, `:middle` or
  `:bottom` then the `y` position will be calculated
  relative to the base image. If `:y` is nil
  (the default) then the image will be placed according
  to the relative offset of the previously composed
  image using `:dy`.

* `:dx` describes the relative offset used to calculate
  the `x` value. `:dx` is an integer offset from the
  edge of the previously composed image. Which edge is
  determined by the `:x_baseline` option. If `:x` is also
  specified then `:x` is first calculated, then `:dx` is
  added to it. In this case, `:x_baseline` is ignored.

* `:dy` describes the relative offset used to calculate
  the `y` value. `:dy` is an integer offset from the
  edge of the previously composed image. Which edge is
  determined by the `:y_baseline` option. If `:y` is also
  specified then `:y` is first calculated, then `:dy` is
  added to it. In this case, `:x_baseline` is ignored.

* `:blend_mode` is the `t:Image.BlendMode.t/0` used when
  composing this image over its base image. The default
  is `:over` which is appropriate for most use cases.

* `:x_baseline` establishes the baseline on the
  previously composed image from which `:dx` is
  calculated. The default is `:right`.

* `:y_baseline` establishes the baseline on the
  previously composed image from which `:dy` is
  calculated. The default is `:bottom`.

# `t`

```elixir
@type t() :: [composition_option()]
```

Image compoositions options

# `default_composit_options`

---

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