Published unlisted
Edited
Jul 3, 2020
Importers
points = [[100, 100], [400, 100], [700, 400], [100, 400]]
X = curve(points.map(d => d[0]))
Y = curve(points.map(d => d[1]))
{
const context = DOM.context2d(800, 500);
for (let tmax = -5; tmax < 30; tmax += .1) {
context.clearRect(0, 0, 800, 500);
// long spiral
context.beginPath();
for (let t = -5; t < tmax; t += .01) {
const alpha = 1 - t / 30;
context.lineTo(
alpha * X(t) + (1 - alpha) * 250,
alpha * Y(t) + (1 - alpha) * 250
);
}
context.lineWidth = .5;
context.stroke();
// main domain
context.beginPath();
for (let t = 0; t < 1; t += .001) {
const alpha = 1;
context.lineTo(
alpha * X(t) + (1 - alpha) * 250,
alpha * Y(t) + (1 - alpha) * 250
);
}
context.lineWidth = 2;
context.stroke();
// data points
context.fillStyle = "red";
for (const p of points) {
context.beginPath();
context.arc(...p, 3, 0, 7);
context.fill();
}
yield context.canvas;
}
return context.canvas;
}
culori = require("culori@0.11.2")
culoriClosed = array => {
const f = culori.interpolateSplineMonotone(d => d, "closed", 1)(array),
n = array.length - 1,
k = 1 + 1 / n;
return t => f(k * (t - Math.floor(t)));
}
function monotone(values, type = "default") {
let n = values.length - 1;
values = values.slice();
switch (type) {
case "default":
values.push(2 * values[n] - values[n - 1]);
values.unshift(2 * values[0] - values[1]);
return t => monotone(clamp(t, 0, 1));
case "closed":
values.unshift(values[n]);
values.push(values[1]);
values.push(values[2]);
n += 2;
const k = 1 - 1 / n;
return t => monotone(k * frac(t));
case "open":
throw new Error('open monotone spline not implemented yet');
}
function monotone(t) {
const i = Math.min(n - 1, Math.floor(t * n)),
y_im1 = values[i],
y_i = values[i + 1],
y_ip1 = values[i + 2],
y_ip2 = values[i + 3],
d = t * n - i,
s_im1 = n * (y_i - y_im1),
s_i = n * (y_ip1 - y_i),
s_ip1 = n * (y_ip2 - y_ip1),
yp_i =
(sign(s_im1) + sign(s_i)) *
min(abs(s_im1), abs(s_i), 0.25 * n * abs(y_ip1 - y_im1)),
yp_ip1 =
(sign(s_i) + sign(s_ip1)) *
min(abs(s_i), abs(s_ip1), 0.25 * n * abs(y_ip2 - y_i));
return (
(((yp_i + yp_ip1 - 2 * s_i) * d + (3 * s_i - 2 * yp_i - yp_ip1)) * d +
yp_i) *
(d / n) +
y_i
);
}
function frac(t) {
return t - Math.floor(t);
}
function clamp(t, min, max) {
return Math.min(max, Math.max(min, t));
}
}
function monotoneClosed(values) {
return monotone(values, "closed");
}
import { abs, max, min, sign } from "@fil/math"
function cubic(values, type = "default") {
let n = values.length - 1;
values = values.slice();
switch (type) {
case "default":
values.push(2 * values[n] - values[n - 1]);
values.unshift(2 * values[0] - values[1]);
return t => cubic(clamp(t, 0, 1));
case "closed":
values.unshift(values[n]);
values.push(values[1]);
values.push(values[2]);
n += 2;
const k = 1 - 1 / n;
return t => cubic(k * frac(t));
case "open":
throw new Error('open monotone spline not implemented yet');
}
function cubic(t) {
const i = Math.min(n - 1, Math.floor(t * n)),
v0 = values[i],
v1 = values[i + 1],
v2 = values[i + 2],
v3 = values[i + 3],
d = t * n - i,
s20 = v2 - v0,
s31 = v3 - v1,
s21 = (v2 - v1) * 2;
return (
(d / 2) *
(((s20 + s31 - 2 * s21) * d + (3 * s21 - 2 * s20 - s31)) * d + s20) +
v1
);
}
function frac(t) {
return t - Math.floor(t);
}
function clamp(t, min, max) {
return Math.min(max, Math.max(min, t));
}
}
function cubicClosed(values) {
return cubic(values, "closed");
}
data = [3, 2.8, 2.5, 1, 0.95, 0.8, 0.5, 0.1, 0.05]
import { select } from "@jashkenas/inputs"
d3 = require("d3-interpolate@1")
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