# Play Grid Sizing
**Status**: implemented

The `PlayGrid` widget has a somewhat idiosyncratic sizing
behavior. This doc will capture some of those behaviors.

## Sizing

PlayGrid has two sizing approaches: *fixed* or *shrinkable*. If a grid
is fixed, then it won't change size due to its packing. If it's
shrinkable, then the grid will resize to available space within a
specified range. These approaches are set at creation time through the
*sizing* property, which is an enum.

Regardless of which sizing method is used, the size of a widget is not
determined by the widgets contained within the grid. Instead, the
geometry of the puzzle determines the shape and aspect ratio of the
grid. The size is determined by the `LayoutConfig` for fixed grids,
and by the min/max\_base\_size properties plus the available space for
shrinkable grids.

## Implementation

* There are two ways the Grid widget is updated externally. Either
  through `play_grid_update_state` or
  `play_grid_set_layout_config`. For fixed size-grids, this will set
  the size of the widget based on the geometry of the puzzle.
* On the other hand, for shrinkable grids, this API will update the
  maximum size for the `max_base_size` widget.
* One consequence of that is that we can't set a custom border size
  with resizable grids, as the border\_size is generated by the
  base\_width.