Common classes to create and convert between square grids and hexagonal grids.

In grid space, every cell has a size of 1 unit in width and height. Each grid can define a custom "world space". Conversion between the unit grid and a grid's world space is achieved using either gridToWorldSpace( point ) or worldToGridSpace( point ).

final grid = Grid.square(
    4,                // The grid area should span 4 tiles in each row
    zero: Point(0, 0) // Grid origin in world space
    size: Point(4, 4) // Grid size in world space
);

// Alternatives with hexagonal grid
Grid.hexagonal(4, horizontal: true);
Grid.hexagonal(4, horizontal: false);

// Examples: Snapping circles (center, diameter) to the Grid
final blue   = grid.gridSnapCentered( Point(0.5, 0.5), 1 );
final green  = grid.gridSnapCentered( Point(1,   2  ), 2 );
final pink   = grid.gridSnapCentered( Point(2.5, 1.5), 1 );
final orange = grid.gridSnapCentered( Point(1.5, 3.5), 1 );

// Convert to your custom world space
final worldPosition = grid.gridToWorldSpace(blue);

The following figure exemplifies how the grid space is laid out in each grid type, as well as how the center of a circle can be snapped to the nearest grid point. Transformations in a square grid, horizontal hex grid and vertical hex grid.