https://pathwaystomindfulness.com/render.worker.js

1// /public/render.worker.js
2let canvas, ctx
3let W = 0,
4  H = 0
5let blurBitmap = null
6
7self.onmessage = async (e) => {
8  const d = e.data || {}
9
10  if (d.canvas) {
11    canvas = d.canvas
12    ctx = canvas.getContext('2d', { alpha: true, desynchronized: true })
13    return
14  }
15  if (d.type === 'setSize') {
16    W = d.width | 0
17    H = d.height | 0
18    canvas.width = W
19    canvas.height = H
20    return
21  }
22  if (d.type === 'setBlurBlob' && d.blob) {
23    blurBitmap = await createImageBitmap(d.blob)
24    drawBackground()
25    return
26  }
27  if (d.type === 'drawStripeBlob' && typeof d.y === 'number' && d.blob) {
28    const stripe = await createImageBitmap(d.blob)
29    drawBackground()
30    ctx.drawImage(stripe, 0, d.y | 0)
31    return
32  }
33  if (d.type === 'clearStripe') {
34    drawBackground()
35    return
36  }
37}
38
39function drawBackground() {
40  if (!ctx || !blurBitmap) return
41  ctx.clearRect(0, 0, canvas.width, canvas.height)
42  ctx.drawImage(blurBitmap, 0, 0)
43}