toot medias: extract color from blurhash

src/timelines/RegularToot.tsx

@@ -6,6 +6,7 @@ import {
   Show,
   createRenderEffect,
   createEffect,
+  createMemo,
 } from "solid-js";
 import tootStyle from "./toot.module.css";
 import { formatRelative } from "date-fns";
@@ -29,13 +30,13 @@ import { Divider } from "@suid/material";
 import cardStyle from "../material/cards.module.css";
 import Button from "../material/Button.js";
 import MediaAttachmentGrid from "./MediaAttachmentGrid.js";
-import { FastAverageColor } from "fast-average-color";
 import Color from "colorjs.io";
 import { useDateFnLocale } from "../platform/i18n";
 import { canShare, share } from "../platform/share";
 import { makeAcctText, useDefaultSession } from "../masto/clients";
 import TootContent from "./toot-components/TootContent";
 import BoostIcon from "./toot-components/BoostIcon";
+import { averageColorHex } from "../platform/blurhash";
 
 type TootActionGroupProps<T extends mastodon.v1.Status> = {
   onRetoot?: (value: T) => void;
@@ -205,31 +206,44 @@ export function TootPreviewCard(props: {
     }
   });
 
-  const onImgLoad = (event: Event & { currentTarget: HTMLImageElement }) => {
-    // TODO: better extraction algorithm
-    // I'd like to use a pattern panel and match one in the panel from the extracted color
-    const fac = new FastAverageColor();
-    const result = fac.getColor(event.currentTarget);
-    if (result.error) {
-      console.error(result.error);
-      fac.destroy();
+  const imgAverageColor = createMemo(() => {
+    if (!props.src.image) return;
+    return new Color(averageColorHex(props.src.blurhash));
+  });
+
+  const prefersWhiteText = createMemo(() => {
+    const oc = imgAverageColor();
+    if (!oc) return;
+    const colorWhite = new Color("white");
+
+    return colorWhite.luminance / oc.luminance > 3.5;
+  });
+
+  const focusSurfaceColor = createMemo(() => {
+    const oc = imgAverageColor();
+    if (!oc) return;
+    if (prefersWhiteText()) {
+      return new Color(oc).darken(0.2);
+    } else {
+      return new Color(oc).lighten(0.2);
+    }
+  });
+
+  const textColorName = createMemo(() => {
+    const useWhiteText = prefersWhiteText();
+    if (typeof useWhiteText === "undefined") {
       return;
     }
-    root.style.setProperty("--tutu-color-surface", result.hex);
-    const focusSurface = result.isDark
-      ? new Color(result.hex).darken(0.2)
-      : new Color(result.hex).lighten(0.2);
-    root.style.setProperty("--tutu-color-surface-d", focusSurface.toString());
-    const textColor = result.isDark ? "white" : "black";
-    const secondaryTextColor = new Color(textColor);
-    secondaryTextColor.alpha = 0.75;
-    root.style.setProperty("--tutu-color-on-surface", textColor);
-    root.style.setProperty(
-      "--tutu-color-secondary-text-on-surface",
-      secondaryTextColor.toString(),
-    );
-    fac.destroy();
-  };
+    return useWhiteText ? "white" : "black";
+  });
+
+  const secondaryTextColor = createMemo(() => {
+    const tcn = textColorName();
+    if (!tcn) return;
+    const tc = new Color(tcn);
+    tc.alpha = 0.75;
+    return tc;
+  });
 
   return (
     <a
@@ -238,12 +252,18 @@ export function TootPreviewCard(props: {
       href={props.src.url}
       target="_blank"
       referrerPolicy="unsafe-url"
+      style={{
+        "--tutu-color-surface": imgAverageColor()?.toString(),
+        "--tutu-color-surface-d": focusSurfaceColor()?.toString(),
+        "--tutu-color-on-surface": textColorName(),
+        "--tutu-color-secondary-text-on-surface":
+          secondaryTextColor()?.toString(),
+      }}
     >
       <Show when={props.src.image}>
         <img
           crossOrigin="anonymous"
           src={props.src.image!}
-          onLoad={onImgLoad}
           width={props.src.width || undefined}
           height={props.src.height || undefined}
           loading="lazy"
@@ -373,16 +393,16 @@ const RegularToot: Component<TootCardProps> = (props) => {
         <Show when={!!status().reblog}>
           <div class={tootStyle.tootRetootGrp}>
             <BoostIcon />
-              <Body2
-                ref={(e: { innerHTML: string }) => {
-                  createRenderEffect(() => {
-                    e.innerHTML = resolveCustomEmoji(
-                      status().account.displayName,
-                      toot().emojis,
-                    );
-                  });
-                }}
-              ></Body2>
+            <Body2
+              ref={(e: { innerHTML: string }) => {
+                createRenderEffect(() => {
+                  e.innerHTML = resolveCustomEmoji(
+                    status().account.displayName,
+                    toot().emojis,
+                  );
+                });
+              }}
+            ></Body2>
             <span>boosts</span>
           </div>
         </Show>