visit(callback, collection)

Iterates cells in row-major order and calls callback({ row, col, value }) for each cell whose value is contained in collection (Array or Set). Return false from the callback to stop early. Reading and mutating the grid inside the callback is allowed.

Example

(move mouse to highlight 🐸 filled cells in the hovered col, and click to randomize q)

code

Quadrille.cellLength = 50;
let q, hint;

const monkeys = ['🙈', '🙉', '🙊', '🦧'];
const birds = ['🐍', '🦜', '🦚', '🐤'];
const emojis = [...monkeys, ...birds, '🐸', '🐯', '🐱', '🐶', '🐮'];

function setup() {
  createCanvas(8 * Quadrille.cellLength, 8 * Quadrille.cellLength);
  highlight();
}

function draw() {
  background('#DAF7A6');
  drawQuadrille(q);
  drawQuadrille(hint);
}

function mousePressed() {
  highlight();
}

function highlight() {
  q = createQuadrille(8, 8);
  // fill q with random emojis
  q.visit(({ row, col }) => q.fill(row, col, random(emojis)));
  hint = createQuadrille(8, 8);
  // mark monkey positions
  q.visit(({ row, col }) => hint.fill(row, col, color(0, 140)), monkeys);
}

The first loop fills all cells with random emojis using visit(callback).
The second loop visits only monkey cells, marking them in a separate quadrille.

Syntax

visit(callback, collection)

Parameters

Param	Description
`callback`	Receives `{ row, col, value }`. Return `false` to stop early; any other return is ignored
`collection`	An `Array` or `Set` of values. Only cells whose value is in the collection are visited

visit(callback)visit(callback, predicate)