added grain + spiky blob

web/src/main.ts

@@ -57,6 +57,8 @@ const sheets = {
 if ("serviceWorker" in navigator && import.meta.env.PROD) {
   navigator.serviceWorker.register("/sw.js", { scope: "/" }).catch((err) => console.warn("no service worker:", err));
 }
+paintGrain();
+
 const cards: Card[] = [];
 let active = -1;
 let loading = false;
@@ -1172,6 +1174,24 @@ function signedIn(user: User, pl8list?: Pl8Status): void {
   if (!cards.length) openLinkOrFeed();
 }
 
+/// The tile of film grain the stylesheet lays under the page's content: faint
+/// specks, each a little lighter or darker than what is under it.
+function paintGrain(): void {
+  const size = 128;
+  const c = document.createElement("canvas");
+  c.width = c.height = size;
+  const ctx = c.getContext("2d");
+  if (!ctx) return;
+  const img = ctx.createImageData(size, size);
+  for (let i = 0; i < img.data.length; i += 4) {
+    const v = Math.random() < 0.5 ? 0 : 255;
+    img.data[i] = img.data[i + 1] = img.data[i + 2] = v;
+    img.data[i + 3] = Math.random() * 30;
+  }
+  ctx.putImageData(img, 0, 0);
+  document.documentElement.style.setProperty("--grain", `url(${c.toDataURL()})`);
+}
+
 /// `/?t=handle/slug` opens on that track; the feed carries on after it.
 async function openLinkOrFeed(): Promise<void> {
   const link = new URLSearchParams(location.search).get("t")?.split("/");