Published
Edited
Apr 5, 2022
50 stars
// https://observablehq.com/@fil/chord-area-inverse
chordAreaInverse = x => Math.pow(x, 0.6) - Math.pow(1 - x, 0.6)
function discUniformTransport1(points, radius) {
const n = points.length / 2,
indices = d3.range(n);
const a = 2 * Math.PI * Math.random(),
sa = Math.sin(a),
ca = Math.cos(a);
const projection = Array.from({ length: indices.length });
for (let i = 0; i < projection.length; i++)
projection[i] = ca * points[2 * i] + sa * points[2 * i + 1];
indices.sort((i, j) => projection[i] - projection[j]);
for (let k = 0; k < n; k++) {
const i = indices[k],
ideal = radius * chordAreaInverse((k + 1) / (n + 1)),
delta = ideal - projection[i];
points[2 * i] += ca * delta;
points[2 * i + 1] += sa * delta;
}
}
discUniformTransportBatched = {
let indices = [],
projection,
deltas;
// batched
return (
points,
radius,
{ dirs = 3, strength = 1, profile = chordAreaInverse } = {}
) => {
const n = points.length / 2;
if (n !== indices.length) {
indices = Uint32Array.from(d3.range(n));
projection = new Float32Array(n);
deltas = new Float32Array(2 * n);
}
const a = 2 * Math.PI * Math.random();
deltas.fill(0);
for (let d = 0; d < dirs; d++) {
const ap = a + (Math.PI * d) / dirs,
sa = Math.sin(ap),
ca = Math.cos(ap);
for (let i = 0; i < n; i++)
projection[i] = ca * points[2 * i] + sa * points[2 * i + 1];
indices.sort((i, j) => projection[i] - projection[j]);
for (let k = 0; k < n; k++) {
const i = indices[k],
ideal = radius * profile(k / (n + 1)),
delta = ideal - projection[i];
deltas[2 * i] += ca * delta;
deltas[2 * i + 1] += sa * delta;
}
}
for (let i = 0; i < points.length; i++)
points[i] += (deltas[i] / dirs) * strength;
};
}
function rectangleUniformTransport(points, x, y, { strength = 1 } = {}) {
const n = points.length / 2,
indices = d3.range(n);
const projection = Array.from({ length: indices.length });
// horizontal
for (let i = 0; i < projection.length; i++) projection[i] = points[2 * i];
indices.sort((i, j) => projection[i] - projection[j]);
for (let k = 0; k < n; k++) {
const i = indices[k],
ideal = x * ((k + 1) / (n + 1)),
delta = ideal - projection[i];
points[2 * i] += delta * strength;
}
// vertical
for (let i = 0; i < projection.length; i++) projection[i] = points[2 * i + 1];
indices.sort((i, j) => projection[i] - projection[j]);
for (let k = 0; k < n; k++) {
const i = indices[k],
ideal = y * ((k + 1) / (n + 1)),
delta = ideal - projection[i];
points[2 * i + 1] += delta * strength;
}
}
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.