Public
Edited
Dec 28, 2023
1 fork
canvas = {
const context = DOM.context2d(width, height);
const projection = d3.geoIdentity().scale(width / n);
const path = d3.geoPath(projection, context);
context.lineWidth = 2;
context.lineJoin = "round";
context.strokeStyle = "magenta";
context.drawImage(image, 0, 0, width, height);
context.beginPath();
path(contours.contour(values, 0.01));
context.stroke();
return context.canvas;
}
3 << 2
contours.contour(values, 0.01)
values = {
const canvas = document.createElement("canvas");
canvas.width = n;
canvas.height = m;
const context = canvas.getContext("2d");
context.drawImage(image, 0, 0);
const data = context.getImageData(0, 0, n, m);
const values = new Float64Array(n * m);
console.log("data", data);
let colors = {};
for (let j = 0, k = 0; j < m; ++j) {
for (let i = 0; i < n; ++i, ++k) {
values[k] = data.data[k << 2] / 255;
}
}
// return values;
return d3.blur2({ data: values, width: n }, 1).data;
}
contours = d3.contours().size([n, m]).smooth(true).thresholds(20)
m = image.naturalHeight
n = image.naturalWidth
image = Object.assign(
await FileAttachment("20230926_18_F30_wafs_300_wspd_m.png").image(),
{ style: "max-height: 33px; display: block;" }
)
height = 600
width=900
d3 = require("d3@7.6.0/dist/d3.min.js") // d3.blur was introduced in d3-array@3.2 and d3@7.6
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