# `tek_layout`

this crate exposes several layout operators
which work entirely in unsigned coordinates
and are generic over `tek_engine::Engine`
and `tek_engine::Content`. chiefly, they
are not dependent on rendering framework.

|operator|description|
|-|-|
|**`When(x, a)`**|render `a` only when `x == true`|
|**`Either(x, a, b)`**|render `a` when `x == true`, otherwise render `b`|
|**`Map(get_iterator, callback)`**|transform items in uniform way|
|**`Bsp`**|concatenative layout|
|...|...|
|**`Align`**|pin content along axis|
|...|...|
|**`Fill`**|**make content's dimension equal to container's:**|
|`Fill::x(a)`|use container's width for content|
|`Fill::y(a)`|use container's height for content|
|`Fill::xy(a)`|use container's width and height for content|
|**`Fixed`**|**assign fixed dimension to content:**|
|`Fixed::x(w, a)`|use width `w` for content|
|`Fixed::y(w, a)`|use height `w` for content|
|`Fixed::xy(w, h, a)`|use width `w` and height `h` for content|
|**`Expand`/`Shrink`**|**change dimension of content:**|
|`Expand::x(n, a)`/`Shrink::x(n, a)`|increment/decrement width of content area by `n`|
|`Expand::y(n, a)`/`Shrink::y(n, a)`|increment/decrement height of content area by `m`|
|`Expand::xy(n, m, a)`/`Shrink::xy(n, m, a)`|increment/decrement width of content area by `n`, height by `m`|
|**`Min`/`Max`**|**constrain dimension of content:**|
|`Min::x(w, a)`/`Max::x(w, a)`|enforce minimum/maximum width `w` for content|
|`Min::y(h, a)`/`Max::y(h, a)`|enforce minimum/maximum height `h` for content|
|`Min::xy(w, h, a)`/`Max::xy(w, h, a)`|enforce minimum/maximum width `w` and height `h` for content|
|**`Push`/`Pull`**|**move content along axis:**|
|`Push::x(n, a)`/`Pull::x(n, a)`|increment/decrement `x` of content area|
|`Push::y(n, a)`/`Pull::y(n, a)`|increment/decrement `y` of content area|
|`Push::xy(n, m, a)`/`Pull::xy(n, m, a)`|increment/decrement `x` and `y` of content area|

**todo:**
* sensible `Margin`/`Padding`
* `Reduce`