Producing open source analytics and vis @Kitware.
{
let k = (cellHeight - 1) * cellWidth;
const width = cellWidth * (cellSize + cellSpacing) + cellSpacing;
const height = cellHeight * (cellSize + cellSpacing) + cellSpacing;
const parent = Object.assign(new Array(cellHeight * cellWidth), {[k]: -1});
const context = DOM.context2d(width, height, 1);
context.canvas.style.imageRendering = "pixelated";
context.fillStyle = "#777";
context.fillRect(0, 0, width, height);
context.fillStyle = "#fff";
fillCells(context);
let iter = 0;
for (const [i, j] of explore(k, parent)) {
context.fillStyle = sinebow(Date.now() / 10000);
fillPath(context, k, parent);
context.fillStyle = "#000";
fillPath(context, k = j, parent);
if (iter % 10 === 0) {
yield context.canvas;
}
iter++;
if (score(k) === 0) break;
}
yield context.canvas;
}
function score(i) {
return Math.random();
}
function* explore(start, parent) {
const frontier = new Queue([start], (a, b) => score(a) - score(b));
let i, j;
while ((i = frontier.pop()) !== undefined) {
if (cells[i] & E && parent[j = i + 1] === undefined) {
parent[j] = i;
frontier.push(j);
yield [i, j];
}
if (cells[i] & W && parent[j = i - 1] === undefined) {
parent[j] = i;
frontier.push(j);
yield [i, j];
}
if (cells[i] & S && parent[j = i + cellWidth] === undefined) {
parent[j] = i;
frontier.push(j);
yield [i, j];
}
if (cells[i] & N && parent[j = i - cellWidth] === undefined) {
parent[j] = i;
frontier.push(j);
yield [i, j];
}
}
}
function generate(cellWidth, cellHeight) {
const heap = new Queue([], (a, b) => a.value - b.value);
const cells = new Uint8Array(cellWidth * cellHeight);
let edge;
heap.push({index: 0, direction: N, value: Math.random()});
heap.push({index: 0, direction: E, value: Math.random()});
while (edge = heap.pop()) {
let i0 = edge.index, i1;
let d0 = edge.direction, d1;
let x0 = i0 % cellWidth, x1;
let y0 = i0 / cellWidth | 0, y1;
if (d0 === N) i1 = i0 - cellWidth, x1 = x0, y1 = y0 - 1, d1 = S;
else if (d0 === S) i1 = i0 + cellWidth, x1 = x0, y1 = y0 + 1, d1 = N;
else if (d0 === W) i1 = i0 - 1, x1 = x0 - 1, y1 = y0, d1 = E;
else i1 = i0 + 1, x1 = x0 + 1, y1 = y0, d1 = W;
if (cells[i1] === 0) {
cells[i0] |= d0, cells[i1] |= d1;
if (y1 > 0 && cells[i1 - cellWidth] === 0) {
heap.push({index: i1, direction: N, value: Math.random()});
}
if (y1 < cellHeight - 1 && cells[i1 + cellWidth] === 0) {
heap.push({index: i1, direction: S, value: Math.random()});
}
if (x1 > 0 && cells[i1 - 1] === 0) {
heap.push({index: i1, direction: W, value: Math.random()});
}
if (x1 < cellWidth - 1 && cells[i1 + 1] === 0) {
heap.push({index: i1, direction: E, value: Math.random()});
}
}
}
return cells;
}
function fillCells(context) {
for (let y = 0, i = 0; y < cellHeight; ++y) {
for (let x = 0; x < cellWidth; ++x, ++i) {
fillCell(context, i);
if (cells[i] & S) fillEdge(context, i, i + cellWidth);
if (cells[i] & E) fillEdge(context, i, i + 1);
}
}
}
function fillCell(context, i) {
const x = i % cellWidth;
const y = i / cellWidth | 0;
context.fillRect(
x * cellSize + (x + 1) * cellSpacing,
y * cellSize + (y + 1) * cellSpacing,
cellSize, cellSize
);
}
function fillEdge(context, i, j) {
if (j < i) [j, i] = [i, j];
const x = i % cellWidth;
const y = i / cellWidth | 0;
if (i === j - 1) {
context.fillRect(
(x + 1) * (cellSize + cellSpacing),
y * cellSize + (y + 1) * cellSpacing,
cellSpacing, cellSize
);
} else {
context.fillRect(
x * cellSize + (x + 1) * cellSpacing,
(y + 1) * (cellSize + cellSpacing),
cellSize, cellSpacing
);
}
}
function fillPath(context, i1, parent) {
while (true) {
fillCell(context, i1);
const i0 = parent[i1];
if (i0 < 0) return;
fillEdge(context, i1, i0);
i1 = i0;
}
}
cells = replay, generate(cellWidth, cellHeight)
cellSize = 3
cellSpacing = 1
cellWidth = Math.floor((width - cellSpacing) / (cellSize + cellSpacing))
cellHeight = Math.floor((600 - cellSpacing) / (cellSize + cellSpacing))
N = 1 << 0
S = 1 << 1
W = 1 << 2
E = 1 << 3
function sinebow(t) {
return "#" + [0, 1, 2].map(i => {
const v = 255 * Math.sin(Math.PI * (t + i / 3)) ** 2;
return Math.round(v).toString(16).padStart(2, "0");
}).join("");
}
Queue = require("tinyqueue@2")
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.