@thi.ng/hiccup-canvas/packed-points.js

Hiccup shape tree renderer for vanilla Canvas 2D contexts

import { TAU } from "@thi.ng/math/api";
const packedPoints = (ctx, attribs, opts, pts) => {
  let v;
  if ((v = attribs.fill) && v !== "none") {
    __drawPoints(ctx, opts, pts, "fill", "fillRect");
  }
  if ((v = attribs.stroke) && v !== "none") {
    __drawPoints(ctx, opts, pts, "stroke", "strokeRect");
  }
};
const __drawPoints = (ctx, opts, pts, cmd, cmdR) => {
  const { start = 0, cstride = 1, estride = 2, size = 1 } = opts;
  let num = opts && opts.num != null ? opts.num : (pts.length - start) / estride | 0;
  if (opts.shape === "circle") {
    for (let i = start; num-- > 0; i += estride) {
      ctx.beginPath();
      ctx.arc(pts[i], pts[i + cstride], size, 0, TAU);
      ctx[cmd]();
    }
  } else {
    const r = size / 2;
    for (let i = start; num-- > 0; i += estride) {
      ctx[cmdR](pts[i] - r, pts[i + cstride] - r, size, size);
    }
  }
};
export {
  packedPoints
};