Grid layout

Status: implemented

The GridLayout system is used to encapsulate the appearance of a crossword into a relatively light-weight structure.

It is calculated from a XwordState, and contains roughly the following information within it:

  • The shape and layout of the board

  • The current string to display in each cell

  • The current cell state, for setting CSS values

  • Any decorations to include in the overlay (see

  • The current sizing and zoom level to render

It can be used by PlayGrid and PlayCell to render themselves appropriately. It can also be used to generate a pdf for printing support.


Grid layout for crosswords.

Consider a 3x3 board:


Each character there is a layout item: + are intersections, | are vertical vborders, - are horizontal borders, and C are cells.

We have (2 * board_rows + 1) * (2 * board_columns + 1) items here.

For consistency, we distinguish between board_rows (rows of cells in the crossword), and grid_rows (rows of layout items in the GridLayout) — and similarly for board_columns vs. grid_columns.


grid_rows = 2 * board_rows + 1
grid_columns = 2 * board_columns + 1

The drawing code can iterate linearly through the grid, and get a LayoutItemKind for each position. That way it knows whether it must draw an intersection, a border, or a cell. Then it can ask for each particular item kind and get its details.

Note: For crossword-style puzzles, the type of each layout item is completely predictable regardless of the puzzle. That is why grid_layout_get_kind doesn’t take a layout as an argument.