ring(row, col, dimension, wrap)

Returns a new quadrille representing the square ring of neighboring cells of radius dimension centered at (row, col). When wrap is true, indices wrap toroidally across borders; when false (default), out-of-bounds positions are treated as empty. The result has size (2·dimension + 1) × (2·dimension + 1).

Example

(click on canvas, move mouse and press keys 1 to 4)

code

Quadrille.cellLength = 20;
let quadrille, ring, hint;
let dimension = 1;
let lime, olive, yellow, fuchsia;
let wrap;

function setup() {
  createCanvas(400, 200);
  lime = color('lime');
  yellow = color('yellow');
  olive = color('olive');
  fuchsia = color('fuchsia');
  quadrille = createQuadrille(10, 10, 25, lime);
  quadrille.rand(20, olive).rand(30, yellow).fill(fuchsia);
  hint = createQuadrille(dimension * 2 + 1, dimension * 2 + 1);
  wrap = createCheckbox(' wrap', false);
  wrap.position(400 - 70, 200 - 22);
  wrap.changed(() => update());
  update();
}

function draw() {
  background('coral');
  drawQuadrille(quadrille, { outline: 'white', row: 0, col: 0 });
  drawQuadrille(hint, { outline: 'cyan', row: quadrille.mouseRow - dimension,
                        col: quadrille.mouseCol - dimension });
  drawQuadrille(ring, { outline: 'cyan', row: 0, col: 11 });
  text('dimension ' + dimension, 210, 195);
}

function mouseMoved() {
  update();
}

function keyPressed() {
  // convert string to number using +
  dimension = +key;
  dimension = constrain(dimension ||= 1, 1, 4);
  hint.width = hint.height = dimension * 2 + 1;
  update();
}

function update() {
  ring = quadrille.ring(quadrille.mouseRow,
                        quadrille.mouseCol,
                        dimension,
                        wrap.checked());
}

Syntax

ring(row, col, [dimension = 1], [wrap = false])

Parameters

Param	Description
`row`	Number: col number of the cell to be read [0..height]
`col`	Number: row number of the cell to be read [0..width]
`dimension`	Number: ring dimension default is 1
`wrap`	Boolean: when `true`, indices wrap toroidally at borders; when `false` (default), out-of-bounds cells are taken as empty

crop(row, col, width, height, wrap)