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Sep 15, 2022
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Graphs
graph = createGraph(nodes)
run0 = shortest_tree({
origins: [nodes.length - 1],
graph,
step: stepbystep ? 1 : 0
})
color = d3
.scaleSequential(interpolateRoma)
.domain([0, width])
.nice()
euclidian = (p, q) => Math.hypot(p[0] - q[0], p[1] - q[1])
function draw_points(context, points, opts = {}) {
const TAU = 2 * Math.PI;
const {radius = 3, fill = "white", stroke = "black", lineWidth = 1} = opts;
context.beginPath();
points.forEach(p => {
context.moveTo(p[0] + radius, p[1]);
context.arc(p[0], p[1], radius, 0, TAU);
});
if (fill) {
context.fillStyle = fill;
context.fill();
}
if (stroke && lineWidth) {
context.lineWidth = lineWidth;
context.strokeStyle = stroke;
context.stroke();
}
}
function draw_special_points(context, points) {
draw_points(context, points, {fill: "orange"});
}
function draw_starting_points(context, points, opts = {}) {
const radius = 5;
draw_points(context, points, {radius, lineWidth: 1.5});
context.font = "14px Arial";
context.textBaseline = "middle";
if (points.length > 1 && opts.labels)
points.forEach((p, i) => {
context.fillText(
String.fromCodePoint("A".charCodeAt(0) + i),
p[0] + radius + 4,
p[1]
);
});
}
function draw_connections(context, nodes, run) {
context.beginPath();
run.predecessor.forEach((d, i) => {
if (d > -1) {
context.moveTo(...nodes[i]);
context.lineTo(...nodes[d]);
}
});
context.lineWidth = 0.5;
context.strokeStyle = "white";
context.stroke();
}
function draw_voronoi_cells(context, nodes, run) {
const width = parseInt(context.canvas.style.width),
height = (context.canvas.height / context.canvas.width) * width,
voronoi = d3.Delaunay.from(nodes).voronoi([0, 0, width, height]);
let i = 0;
for (const cell of voronoi.cellPolygons()) {
context.strokeStyle = context.fillStyle = color(run.cost[i]);
context.beginPath(),
voronoi.renderCell(i, context),
context.fill(),
context.stroke();
i++;
}
}
function draw_contours(context, nodes, run, opts = {}) {
const path = d3.geoPath().context(context),
contours = d3.tricontour().thresholds(opts.quick ? 50 : 300)(
nodes.map((d, i) => [d[0], d[1], run.cost[i]]).filter(d => isFinite(d[2]))
);
context.lineWidth = 1;
for (const c of contours) {
context.strokeStyle = context.fillStyle = color(c.value);
context.beginPath();
path(c);
context.fill();
context.stroke();
}
if (opts.lines) {
context.strokeStyle = "white";
context.fillStyle = "white";
context.textAlign = "center";
context.font = "12px Arial";
context.globalAlpha = 1;
for (const c of contours) {
if (c.value % 20 === 0) {
context.lineWidth = c.value % 100 === 0 ? 1 : 0.5;
if (opts.labels && !opts.quick && c.value % 100 === 0) {
drawLabels(context, c);
} else {
context.beginPath();
path(c);
context.stroke();
}
}
}
}
}
// adapted from https://observablehq.com/@fil/contour-labels-canvas
function drawLabels(context, contour) {
const width = parseInt(context.canvas.style.width),
height = (context.canvas.height / context.canvas.width) * width,
scale = 1,
path = d3.geoPath().context(context);
const threshold = contour.value,
labels = [],
steps = 30;
contour.coordinates.forEach(polygon =>
polygon.forEach((ring, j) => {
const p = ring.slice(1, Infinity),
// best number of steps to divide ring.length
possibilities = d3.range(steps, steps * 1.4),
scores = possibilities.map(d => -((p.length - 1) % d)),
n = possibilities[d3.scan(scores)],
// best starting point: bottom for first rings, top for holes
start = 1 + (d3.scan(p.map(xy => (j === 0 ? -1 : 1) * xy[1])) % n),
margin = 2;
if (p.length < 15) return; // no label on small contours
p.forEach((xy, i) => {
if (
i % n === start &&
xy[0] > margin &&
xy[0] < width - margin &&
xy[1] > margin &&
xy[1] < height - margin
) {
const a = (i - 2 + p.length) % p.length,
b = (i + 2) % p.length,
dx = p[b][0] - p[a][0],
dy = p[b][1] - p[a][1];
if (dx === 0 && dy === 0) return;
labels.push({
threshold, // value
xy: xy.map(d => scale * d),
angle: Math.atan2(dy, dx),
text: `${threshold}`
});
}
});
})
);
// create the mask for this threshold:
// the full rectangle minus a rectangle around each label
context.save();
context.beginPath();
context.moveTo(0, 0),
context.lineTo(width, 0),
context.lineTo(width, height),
context.lineTo(0, height),
context.lineTo(0, 0);
const arc = d3.arc();
for (const label of labels) {
for (let i = 0; i < 2 * Math.PI; i += 0.2) {
const pos = [Math.cos(i) * 13, -Math.sin(i) * 10],
c = Math.cos(label.angle),
s = Math.sin(label.angle);
context[i === 0 ? "moveTo" : "lineTo"](
label.xy[0] + pos[0] * c - pos[1] * s,
label.xy[1] + pos[1] * c + pos[0] * s
);
}
}
// context.stroke(); // uncomment to see the mask
context.clip();
// draw white contour for this threshold
context.beginPath();
path(contour);
context.stroke();
// draw labels for this threshold
context.restore();
for (const label of labels) {
addlabel(context, label);
}
function addlabel(context, label) {
context.save();
context.translate(...label.xy);
context.rotate(label.angle + (Math.cos(label.angle) < 0 ? Math.PI : 0));
context.fillText(label.text, -1, 4);
context.restore();
}
}
// adapted from https://observablehq.com/@d3/hello-d3-drag
drag = (agents, draw, end) => {
// When starting a drag gesture, move the subject to the top and mark it as active.
function dragstarted() {
d3.select(this).style("cursor", "grabbing");
}
// When dragging, update the subject’s position.
async function dragged() {
const agent = d3.event.subject;
agent[0] = Math.max(0, Math.min(width, d3.event.x));
agent[1] = Math.max(0, Math.min(height, d3.event.y));
await draw(true);
}
// When ending a drag gesture, mark the subject as inactive again.
function dragended() {
// d3.event.subject.active = false;
d3.select(this).style("cursor", "grab");
if (end) end();
draw();
}
function dragsubject(event) {
const radius = 30;
if (!event) event = d3.event;
let subject = null;
let distance = radius * 1.5;
for (const c of agents) {
let d = Math.hypot(event.x - c[0], event.y - c[1]);
if (d < distance) {
distance = d;
subject = c;
}
}
return subject;
}
return function(sel) {
sel
.style("cursor", "pointer")
.call(
d3
.drag()
.subject(dragsubject)
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended)
)
.on("mousemove", function() {
const m = d3.mouse(this),
subject = dragsubject({ x: m[0], y: m[1] });
d3.select(this).style("cursor", subject ? "grab" : "pointer");
});
};
}
rng = Math.random
import { pick2d } with { rng } from "@fil/2d-point-distributions"
height = 400
d3 = require("d3@5", "d3-delaunay@5", "d3-tricontour@0.1")
import { legend } from "@d3/color-legend"
import { checkbox } from "@jashkenas/inputs"
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