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src/components/article/ThumbHashImage.jsx

@@ -1,6 +1,48 @@
 import { useEffect, useRef } from 'react';
 import Box from '@mui/material/Box';
-import { thumbHashToRGBA } from 'thumbhash';
+import { thumbHashToRGBA, thumbHashToDataURL } from 'thumbhash';
+
+const dataUrlCache = (globalThis.__THUMB_DATA_URL_CACHE__ ??= new Map());
+const loadedImageHashes = (globalThis.__LOADED_IMAGE_HASHES__ ??= new Set());
+export const imageCache = (globalThis.__IMAGE_CACHE__ ??= new Map());
+
+export function isImageLoaded(fullHash) {
+  if (!fullHash) return false;
+  return loadedImageHashes.has(fullHash) || imageCache.has(fullHash);
+}
+
+export function markImageLoaded(fullHash, img) {
+  if (!fullHash) return;
+  loadedImageHashes.add(fullHash);
+  if (img) {
+    imageCache.set(fullHash, img);
+  }
+}
+
+export function getCachedImage(fullHash) {
+  if (!fullHash) return null;
+  const img = imageCache.get(fullHash);
+  if (img && img.complete && img.naturalWidth) {
+    return img;
+  }
+  return null;
+}
+
+export function getThumbHashDataUrl(thumbHash) {
+  if (!thumbHash || typeof thumbHash !== 'string') return null;
+  let url = dataUrlCache.get(thumbHash);
+  if (!url) {
+    try {
+      const bytes = Uint8Array.from(atob(thumbHash), (c) => c.charCodeAt(0));
+      url = thumbHashToDataURL(bytes);
+      dataUrlCache.set(thumbHash, url);
+    } catch (err) {
+      console.warn('[ThumbHashImage] thumbHashToDataURL failed:', err);
+      return null;
+    }
+  }
+  return url;
+}
 
 export function decodeThumbHash(thumbHash) {
   if (!thumbHash || typeof thumbHash !== 'string') return null;

src/components/tiles/ArticleTile.jsx

@@ -6,7 +6,7 @@ import Typography from '@mui/material/Typography';
 import { Tile, tileBaseSx } from 'dashgui/tiles';
 import { formatPrice } from '../../utils/price';
 import { articleSku } from '../article/articleRoute';
-import { decodeThumbHash } from '../article/ThumbHashImage';
+import { getThumbHashDataUrl, getCachedImage, imageCache } from '../article/ThumbHashImage';
 import { BrandLabel } from '../brand';
 import { thumb } from '../../api';
 
@@ -100,12 +100,22 @@ class ArticleTileBackdrop extends PureComponent {
   img = null;
   observer = null;
 
+  constructor(props) {
+    super(props);
+    this.thumbUrl = getThumbHashDataUrl(props.thumbHash);
+    this.img = getCachedImage(props.fullHash);
+  }
+
   componentDidMount() {
     this.loadImage();
   }
 
   componentDidUpdate(prevProps) {
+    if (prevProps.thumbHash !== this.props.thumbHash) {
+      this.thumbUrl = getThumbHashDataUrl(this.props.thumbHash);
+    }
     if (prevProps.fullHash !== this.props.fullHash) {
+      this.img = getCachedImage(this.props.fullHash);
       this.loadImage();
     }
   }
@@ -118,8 +128,15 @@ class ArticleTileBackdrop extends PureComponent {
   loadImage() {
     const { fullHash } = this.props;
     if (fullHash) {
+      const cached = getCachedImage(fullHash);
+      if (cached) {
+        this.img = cached;
+        this.paint();
+        return;
+      }
       const img = new Image();
       img.onload = () => {
+        imageCache.set(fullHash, img);
         if (this.img === img) {
           this.paint();
         }
@@ -127,15 +144,18 @@ class ArticleTileBackdrop extends PureComponent {
       img.src = thumb.url(fullHash);
       this.img = img;
       if (img.complete && img.naturalWidth) {
+        imageCache.set(fullHash, img);
         this.paint();
         return;
       }
     }
-    this.paint();
   }
 
   setCanvas = (canvas) => {
     this.canvasRef = canvas;
+    if (!this.img && this.props.fullHash) {
+      this.img = getCachedImage(this.props.fullHash);
+    }
     if (canvas && typeof ResizeObserver !== 'undefined') {
       this.observer?.disconnect();
       this.observer = new ResizeObserver(() => this.paint());
@@ -157,8 +177,9 @@ class ArticleTileBackdrop extends PureComponent {
     const ctx = canvas.getContext('2d');
     if (!ctx) return;
 
-    const img = this.img;
+    const img = this.img || getCachedImage(this.props.fullHash);
     if (img && img.complete && img.naturalWidth && img.naturalHeight) {
+      this.img = img;
       drawContainedWithStretchedEdges(
         ctx,
         img,
@@ -167,41 +188,49 @@ class ArticleTileBackdrop extends PureComponent {
         dstW,
         dstH,
       );
-      return;
-    }
-
-    const { thumbHash } = this.props;
-    if (thumbHash) {
-      const decoded = decodeThumbHash(thumbHash);
-      if (decoded) {
-        const { w, h, rgba } = decoded;
-        const temp = document.createElement('canvas');
-        temp.width = w;
-        temp.height = h;
-        temp.getContext('2d').putImageData(
-          new ImageData(new Uint8ClampedArray(rgba), w, h),
-          0,
-          0,
-        );
-        drawContainedWithStretchedEdges(ctx, temp, w, h, dstW, dstH);
-      }
     }
   };
 
   render() {
+    const hasCachedImage = Boolean(this.img && this.img.complete && this.img.naturalWidth);
     return (
       <Box
-        component="canvas"
-        ref={this.setCanvas}
-        aria-hidden
         sx={{
           position: 'absolute',
           inset: 0,
           width: '100%',
           height: '100%',
-          display: 'block',
+          overflow: 'hidden',
         }}
-      />
+      >
+        {!hasCachedImage && this.thumbUrl ? (
+          <Box
+            component="img"
+            src={this.thumbUrl}
+            alt=""
+            aria-hidden
+            sx={{
+              position: 'absolute',
+              inset: 0,
+              width: '100%',
+              height: '100%',
+              objectFit: 'cover',
+            }}
+          />
+        ) : null}
+        <Box
+          component="canvas"
+          ref={this.setCanvas}
+          aria-hidden
+          sx={{
+            position: 'absolute',
+            inset: 0,
+            width: '100%',
+            height: '100%',
+            display: 'block',
+          }}
+        />
+      </Box>
     );
   }
 }

src/components/tiles/CategoryTile.jsx

@@ -9,7 +9,7 @@ import SettingsIcon from '@mui/icons-material/Settings';
 import PointOfSaleIcon from '@mui/icons-material/PointOfSale';
 import PhotoCameraIcon from '@mui/icons-material/PhotoCamera';
 import DeleteOutlinedIcon from '@mui/icons-material/DeleteOutlined';
-import ThumbHashImage from '../article/ThumbHashImage';
+import { getThumbHashDataUrl, getCachedImage, imageCache } from '../article/ThumbHashImage';
 import { thumb } from '../../api';
 import { tileBaseSx } from 'dashgui/tiles';
 
@@ -195,36 +195,56 @@ function MiddleBand({ settingsTab, nameInput, terminals, categoryPosterminalIds,
  * ThumbHash is shown immediately as a placeholder; the thumb fades in once loaded.
  */
 class CategoryBackdrop extends PureComponent {
-  state = { thumbLoaded: false };
+  constructor(props) {
+    super(props);
+    this.thumbUrl = getThumbHashDataUrl(props.thumbHash);
+    this.isCached = Boolean(getCachedImage(props.fullHash));
+  }
 
   componentDidUpdate(prevProps) {
+    if (prevProps.thumbHash !== this.props.thumbHash) {
+      this.thumbUrl = getThumbHashDataUrl(this.props.thumbHash);
+    }
     if (prevProps.fullHash !== this.props.fullHash) {
-      this.setState({ thumbLoaded: false });
+      this.isCached = Boolean(getCachedImage(this.props.fullHash));
+      this.forceUpdate();
     }
   }
 
-  handleThumbLoad = () => {
-    this.setState({ thumbLoaded: true });
-  };
-
-  handleThumbError = () => {
-    this.setState({ thumbLoaded: false });
+  handleLoad = (e) => {
+    if (this.props.fullHash && e.target) {
+      imageCache.set(this.props.fullHash, e.target);
+    }
   };
 
   render() {
-    const { thumbHash, fullHash } = this.props;
-    const { thumbLoaded } = this.state;
-    if (!thumbHash && !fullHash) return null;
+    const { fullHash } = this.props;
+    if (!this.thumbUrl && !fullHash) return null;
+    const isCached = this.isCached || Boolean(getCachedImage(fullHash));
     return (
       <Box sx={{ position: 'absolute', inset: 0, zIndex: 0, overflow: 'hidden' }}>
-        {thumbHash && !thumbLoaded ? <ThumbHashImage thumbHash={thumbHash} /> : null}
-        {fullHash ? (
+        {!isCached && this.thumbUrl ? (
           <Box
             component="img"
-            src={thumb.url(fullHash)}
+            src={this.thumbUrl}
             alt=""
-            onLoad={this.handleThumbLoad}
-            onError={this.handleThumbError}
+            aria-hidden
+            sx={{
+              position: 'absolute',
+              inset: 0,
+              display: 'block',
+              width: '100%',
+              height: '100%',
+              objectFit: 'cover',
+            }}
+          />
+        ) : null}
+        {fullHash ? (
+          <Box
+            component="img"
+            src={thumb.url(fullHash)}
+            alt=""
+            onLoad={this.handleLoad}
             sx={{
               position: 'absolute',
               inset: 0,
@@ -232,7 +252,6 @@ class CategoryBackdrop extends PureComponent {
               width: '100%',
               height: '100%',
               objectFit: 'cover',
-              opacity: thumbLoaded ? 1 : 0,
             }}
           />
         ) : null}