chart = {
const context = DOM.context2d(900, 500);
const path = d3.geoPath(projection, context);
function render() {
context.clearRect(0, 0, 900, 500);
context.beginPath(), path(graticule), context.strokeStyle = "#ccc", context.stroke();
context.beginPath(), path(land), context.fillStyle = "#000", context.fill();
context.beginPath(), path(sphere), context.strokeStyle = "#000", context.stroke();
return context.canvas;
}
return d3.select(context.canvas)
.call(drag(projection).on("drag.render", render))
.call(render)
.node();
}
function drag(projection) {
let v0, q0, r0;
function dragstarted() {
v0 = versor.cartesian(projection.invert(d3.mouse(this)));
q0 = versor(r0 = projection.rotate());
}
function dragged() {
const v1 = versor.cartesian(projection.rotate(r0).invert(d3.mouse(this)));
const q1 = versor.multiply(q0, versor.delta(v0, v1));
projection.rotate(versor.rotation(q1));
}
return d3.drag()
.on("start", dragstarted)
.on("drag", dragged);
}
projection = d3.geoHammer().coefficient(Infinity).translate([900 / 2, 500 / 2]).precision(0.1)
sphere = ({type: "Sphere"})
graticule = d3.geoGraticule10()
land = topojson.feature(world, world.objects.countries)
world = d3.json("https://unpkg.com/world-atlas@1/world/110m.json")
versor = require("versor@0.0.3")
topojson = require("topojson-client@3")
d3 = require("d3@5", "d3-geo-projection@2")
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