fix(studio): improve preview loading reliability

2026-09-10 22:20:14 +00:00 · 2026-07-27 22:14:23 -07:00
parent 3c857d768b
commit 18b9acac12
8 changed files with 288 additions and 128 deletions
@@ -40,6 +40,33 @@ function mount(onSelect = vi.fn(), onAddToTimeline = vi.fn()) {
 }

 describe("composition card drag", () => {
+  it("uses a cached image instead of eagerly mounting a live preview iframe", () => {
+    const { host } = mount();
+    expect(host.querySelector('img[src*="/thumbnail/"]')).not.toBeNull();
+    expect(host.querySelector("iframe")).toBeNull();
+  });
+
+  it("mounts one live preview only after sustained hover and removes it on leave", () => {
+    vi.useFakeTimers();
+    const consoleError = vi.spyOn(console, "error").mockImplementation(() => {});
+    try {
+      const { host, card } = mount();
+      act(() => {
+        card.dispatchEvent(new Event("pointerover", { bubbles: true }));
+        vi.advanceTimersByTime(300);
+      });
+      expect(host.querySelectorAll("iframe")).toHaveLength(1);
+
+      act(() => {
+        card.dispatchEvent(new Event("pointerout", { bubbles: true }));
+      });
+      expect(host.querySelector("iframe")).toBeNull();
+    } finally {
+      consoleError.mockRestore();
+      vi.useRealTimers();
+    }
+  });
+
  it("keeps ordinary click navigation", () => {
    const { card, onSelect } = mount();
    act(() => card.click());
@@ -1,5 +1,6 @@
 import { memo, useCallback, useEffect, useRef, useState } from "react";
 import { setPreviewMediaMuted } from "../../player/lib/timelineIframeHelpers";
+import { buildCompositionThumbnailUrl } from "../../player/components/CompositionThumbnail";
 import { TIMELINE_COMPOSITION_MIME } from "../../utils/timelineCompositionDrop";

 interface CompositionsTabProps {
@@ -130,6 +131,7 @@ function CompCard({
 }) {
  const [hovered, setHovered] = useState(false);
  const [stageSize, setStageSize] = useState(DEFAULT_PREVIEW_STAGE);
+  const [livePreviewLoaded, setLivePreviewLoaded] = useState(false);
  const iframeRef = useRef<HTMLIFrameElement | null>(null);
  const hoverTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
  const syncTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
@@ -159,9 +161,16 @@ function CompCard({
      hoverTimer.current = null;
    }
    setHovered(false);
+    setLivePreviewLoaded(false);
  };
  const name = comp.replace(/^compositions\//, "").replace(/\.html$/, "");
  const previewUrl = `/api/projects/${projectId}/preview/comp/${comp}`;
+  const thumbnailUrl = buildCompositionThumbnailUrl({
+    previewUrl,
+    seekTime: 0,
+    duration: THUMBNAIL_SEEK_TIME_SECONDS * 2,
+    origin: window.location.origin,
+  });
  const previewScale = resolveCompositionPreviewScale({
    cardWidth: CARD_W,
    cardHeight: CARD_H,
@@ -172,7 +181,7 @@ function CompCard({
  const thumbnailOffsetY = (CARD_H - stageSize.height * previewScale) / 2;

  useEffect(() => {
-    requestIframePlaybackSync(hovered);
+    if (hovered) requestIframePlaybackSync(true);
  }, [hovered, requestIframePlaybackSync]);

  useEffect(() => {
@@ -216,36 +225,49 @@ function CompCard({
      }`}
    >
      <div className="w-20 h-[45px] rounded overflow-hidden bg-neutral-900 flex-shrink-0 relative">
-        <iframe
-          ref={iframeRef}
-          src={previewUrl}
-          sandbox="allow-scripts allow-same-origin"
+        <img
+          src={thumbnailUrl}
+          alt=""
+          draggable={false}
          loading="lazy"
-          className="absolute border-none pointer-events-none"
-          style={{
-            transformOrigin: "0 0",
-            width: stageSize.width,
-            height: stageSize.height,
-            left: thumbnailOffsetX,
-            top: thumbnailOffsetY,
-            transform: `scale(${previewScale})`,
-          }}
-          onLoad={(e) => {
-            try {
-              const iframe = e.currentTarget;
-              const root = iframe.contentDocument?.querySelector("[data-composition-id]");
-              const width = Number(root?.getAttribute("data-width")) || DEFAULT_PREVIEW_STAGE.width;
-              const height =
-                Number(root?.getAttribute("data-height")) || DEFAULT_PREVIEW_STAGE.height;
-              setStageSize({ width, height });
-              requestIframePlaybackSync(hovered);
-            } catch {
-              setStageSize(DEFAULT_PREVIEW_STAGE);
-            }
-          }}
-          title={`${name} preview`}
-          tabIndex={-1}
+          decoding="async"
+          className={`absolute inset-0 h-full w-full object-contain transition-opacity ${
+            livePreviewLoaded ? "opacity-0" : "opacity-100"
+          }`}
        />
+        {hovered && (
+          <iframe
+            ref={iframeRef}
+            src={previewUrl}
+            sandbox="allow-scripts allow-same-origin"
+            className="absolute border-none pointer-events-none"
+            style={{
+              transformOrigin: "0 0",
+              width: stageSize.width,
+              height: stageSize.height,
+              left: thumbnailOffsetX,
+              top: thumbnailOffsetY,
+              transform: `scale(${previewScale})`,
+            }}
+            onLoad={(e) => {
+              try {
+                const iframe = e.currentTarget;
+                const root = iframe.contentDocument?.querySelector("[data-composition-id]");
+                const width =
+                  Number(root?.getAttribute("data-width")) || DEFAULT_PREVIEW_STAGE.width;
+                const height =
+                  Number(root?.getAttribute("data-height")) || DEFAULT_PREVIEW_STAGE.height;
+                setStageSize({ width, height });
+                setLivePreviewLoaded(true);
+                requestIframePlaybackSync(true);
+              } catch {
+                setStageSize(DEFAULT_PREVIEW_STAGE);
+              }
+            }}
+            title={`${name} preview`}
+            tabIndex={-1}
+          />
+        )}
      </div>
      <div
        className="min-w-0 flex-1"