Fix asset translation

src/main/resources/application.yml

@@ -14,8 +14,10 @@ spring:
   thymeleaf:
     cache: false
   datasource:
-    url: jdbc:sqlite:imgfloat.db
+    url: jdbc:sqlite:imgfloat.db?busy_timeout=5000&journal_mode=WAL
     driver-class-name: org.sqlite.JDBC
+    hikari:
+      connection-init-sql: "PRAGMA journal_mode=WAL; PRAGMA busy_timeout=5000;"
   jpa:
     hibernate:
       ddl-auto: update

src/main/resources/static/js/broadcast.js

@@ -3,6 +3,7 @@ const ctx = canvas.getContext('2d');
 canvas.width = window.innerWidth;
 canvas.height = window.innerHeight;
 const assets = new Map();
+const imageCache = new Map();
 
 function connect() {
     const socket = new SockJS('/ws');
@@ -24,28 +25,46 @@ function renderAssets(list) {
 function handleEvent(event) {
     if (event.type === 'DELETED') {
         assets.delete(event.assetId);
+        imageCache.delete(event.assetId);
     } else if (event.payload && !event.payload.hidden) {
         assets.set(event.payload.id, event.payload);
+        ensureImage(event.payload);
     } else if (event.payload && event.payload.hidden) {
         assets.delete(event.payload.id);
+        imageCache.delete(event.payload.id);
     }
     draw();
 }
 
 function draw() {
     ctx.clearRect(0, 0, canvas.width, canvas.height);
-    assets.forEach(asset => {
-        ctx.save();
-        ctx.globalAlpha = 1;
-        ctx.translate(asset.x, asset.y);
-        ctx.rotate(asset.rotation * Math.PI / 180);
-        const image = new Image();
-        image.src = asset.url;
-        image.onload = () => {
-            ctx.drawImage(image, 0, 0, asset.width, asset.height);
-        };
-        ctx.restore();
-    });
+    assets.forEach(drawAsset);
+}
+
+function drawAsset(asset) {
+    ctx.save();
+    ctx.translate(asset.x, asset.y);
+    ctx.rotate(asset.rotation * Math.PI / 180);
+
+    const image = ensureImage(asset);
+    if (image?.complete) {
+        ctx.drawImage(image, 0, 0, asset.width, asset.height);
+    }
+
+    ctx.restore();
+}
+
+function ensureImage(asset) {
+    const cached = imageCache.get(asset.id);
+    if (cached && cached.src === asset.url) {
+        return cached;
+    }
+
+    const image = new Image();
+    image.onload = draw;
+    image.src = asset.url;
+    imageCache.set(asset.id, image);
+    return image;
 }
 
 window.addEventListener('resize', () => {