feat(studio): per-composition render button in compositions tab

packages/cli/src/server/studioServer.ts

@@ -263,6 +263,7 @@ export function createStudioServer(options: StudioServerOptions): StudioServer {
             format: opts.format,
             outputResolution: opts.outputResolution,
             ...(manualEditsRenderScript ? { renderBodyScripts: [manualEditsRenderScript] } : {}),
+            ...(opts.composition ? { entryFile: opts.composition } : {}),
           });
           const startTime = Date.now();
           const onProgress = (j: { progress: number; currentStage?: string }) => {

packages/core/src/studio-api/routes/render.test.ts

@@ -117,6 +117,83 @@ describe("POST /projects/:id/render — outputResolution forwarding", () => {
   });
 });
 
+describe("POST /projects/:id/render — composition forwarding", () => {
+  it("forwards a valid composition path to the adapter", async () => {
+    const spy = vi.fn();
+    const { app, cleanup } = buildApp(spy);
+    try {
+      const res = await app.request("http://localhost/projects/demo/render", {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({
+          fps: 30,
+          quality: "standard",
+          format: "mp4",
+          composition: "compositions/intro.html",
+        }),
+      });
+      expect(res.status).toBe(200);
+      expect(spy).toHaveBeenCalledOnce();
+      expect(spy.mock.calls[0][0].composition).toBe("compositions/intro.html");
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("omits composition when not specified", async () => {
+    const spy = vi.fn();
+    const { app, cleanup } = buildApp(spy);
+    try {
+      const res = await app.request("http://localhost/projects/demo/render", {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ fps: 30, quality: "standard", format: "mp4" }),
+      });
+      expect(res.status).toBe(200);
+      expect(spy.mock.calls[0][0].composition).toBeUndefined();
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("omits composition when empty string", async () => {
+    const spy = vi.fn();
+    const { app, cleanup } = buildApp(spy);
+    try {
+      const res = await app.request("http://localhost/projects/demo/render", {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ fps: 30, quality: "standard", format: "mp4", composition: "" }),
+      });
+      expect(res.status).toBe(200);
+      expect(spy.mock.calls[0][0].composition).toBeUndefined();
+    } finally {
+      cleanup();
+    }
+  });
+
+  it("rejects path-traversal attempts with 400", async () => {
+    const spy = vi.fn();
+    const { app, cleanup } = buildApp(spy);
+    try {
+      const res = await app.request("http://localhost/projects/demo/render", {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({
+          fps: 30,
+          quality: "standard",
+          format: "mp4",
+          composition: "../../../etc/passwd",
+        }),
+      });
+      expect(res.status).toBe(400);
+      expect(spy).not.toHaveBeenCalled();
+    } finally {
+      cleanup();
+    }
+  });
+});
+
 describe("POST /projects/:id/render — fps wire format", () => {
   // The fps fraction-syntax feature accepts JSON `number` (integer fps) and
   // JSON `string` (ffmpeg-style rational) on the wire, normalizing both to

packages/core/src/studio-api/routes/render.ts

@@ -1,7 +1,7 @@
 import type { Hono } from "hono";
 import { streamSSE } from "hono/streaming";
 import { existsSync, readFileSync, mkdirSync, unlinkSync, readdirSync, statSync } from "node:fs";
-import { join } from "node:path";
+import { join, resolve, sep } from "node:path";
 import type { StudioApiAdapter, RenderJobState } from "../types.js";
 import { VALID_CANVAS_RESOLUTIONS, parseFps, type CanvasResolution } from "../../core.types.js";
 
@@ -59,6 +59,7 @@ export function registerRenderRoutes(api: Hono, adapter: StudioApiAdapter): void
       quality?: string;
       format?: string;
       resolution?: string;
+      composition?: string;
     };
     const VALID_FORMATS = new Set(["mp4", "webm", "mov"]);
     const FORMAT_EXT: Record<string, string> = { mp4: ".mp4", webm: ".webm", mov: ".mov" };
@@ -76,6 +77,14 @@ export function registerRenderRoutes(api: Hono, adapter: StudioApiAdapter): void
     const outputResolution = VALID_RESOLUTIONS.has(body.resolution ?? "")
       ? (body.resolution as CanvasResolution)
       : undefined;
+    let composition: string | undefined;
+    if (typeof body.composition === "string" && body.composition.length > 0) {
+      const resolved = resolve(project.dir, body.composition);
+      if (!resolved.startsWith(resolve(project.dir) + sep)) {
+        return c.json({ error: "composition path must be within the project directory" }, 400);
+      }
+      composition = body.composition;
+    }
 
     const now = new Date();
     const datePart = now.toISOString().slice(0, 10);
@@ -94,6 +103,7 @@ export function registerRenderRoutes(api: Hono, adapter: StudioApiAdapter): void
       quality,
       jobId,
       outputResolution,
+      composition,
     });
     (jobState as RenderJobState & { createdAt: number }).createdAt = Date.now();
     renderJobs.set(jobId, jobState as RenderJobState & { createdAt: number });

packages/core/src/studio-api/types.ts

@@ -88,6 +88,8 @@ export interface StudioApiAdapter {
      * the producer for the integer-scale + aspect + HDR constraints.
      */
     outputResolution?: CanvasResolution;
+    /** Entry file relative to projectDir (e.g. "compositions/intro.html"). Defaults to index.html. */
+    composition?: string;
   }): RenderJobState;
 
   /** Optional: generate a JPEG thumbnail via Puppeteer or similar. */

packages/studio/src/components/StudioLeftSidebar.tsx

@@ -1,11 +1,12 @@
-import type { RefObject } from "react";
+import { useCallback, type RefObject } from "react";
 import { SourceEditor } from "./editor/SourceEditor";
 import { LeftSidebar, type LeftSidebarHandle } from "./sidebar/LeftSidebar";
 import { MediaPreview } from "./MediaPreview";
 import { isMediaFile } from "../utils/mediaTypes";
 import { usePanelLayoutContext } from "../contexts/PanelLayoutContext";
 import { useStudioContext } from "../contexts/StudioContext";
 import { useFileManagerContext } from "../contexts/FileManagerContext";
+import { getPersistedRenderSettings } from "./renders/RenderQueue";
 
 export interface StudioLeftSidebarProps {
   leftSidebarRef: RefObject<LeftSidebarHandle | null>;
@@ -28,7 +29,7 @@ export function StudioLeftSidebar({
     handlePanelResizeMove,
     handlePanelResizeEnd,
   } = usePanelLayoutContext();
-  const { projectId } = useStudioContext();
+  const { projectId, renderQueue, waitForPendingDomEditSaves } = useStudioContext();
   const {
     compositions,
     assets,
@@ -45,6 +46,15 @@ export function StudioLeftSidebar({
     handleContentChange,
   } = useFileManagerContext();
 
+  const handleRenderComposition = useCallback(
+    async (comp: string) => {
+      await waitForPendingDomEditSaves();
+      const { format, quality, fps } = getPersistedRenderSettings();
+      await renderQueue.startRender({ composition: comp, format, quality, fps });
+    },
+    [renderQueue, waitForPendingDomEditSaves],
+  );
+
   if (leftCollapsed) {
     return (
       <div className="flex w-10 flex-shrink-0 flex-col items-center border-r border-neutral-800/50 bg-neutral-950 pt-1">
@@ -107,6 +117,8 @@ export function StudioLeftSidebar({
             )
           ) : undefined
         }
+        onRenderComposition={handleRenderComposition}
+        isRendering={renderQueue.isRendering}
         onLint={onLint}
         linting={linting}
         onToggleCollapse={toggleLeftSidebar}

packages/studio/src/components/StudioRightPanel.tsx

@@ -195,7 +195,17 @@ export function StudioRightPanel({
                   onClearCompleted={renderQueue.clearCompleted}
                   onStartRender={async (format, quality, resolution, fps) => {
                     await waitForPendingDomEditSaves();
-                    await renderQueue.startRender({ fps, quality, format, resolution });
+                    const composition =
+                      activeCompPath && activeCompPath !== "index.html"
+                        ? activeCompPath
+                        : undefined;
+                    await renderQueue.startRender({
+                      fps,
+                      quality,
+                      format,
+                      resolution,
+                      composition,
+                    });
                   }}
                   compositionDimensions={compositionDimensions}
                   isRendering={renderQueue.isRendering}

packages/studio/src/components/renders/RenderQueue.tsx

@@ -1,7 +1,34 @@
-import { memo, useState, useRef, useEffect } from "react";
+import { memo, useState, useRef, useEffect, useCallback } from "react";
 import { RenderQueueItem } from "./RenderQueueItem";
 import type { RenderJob, ResolutionPreset } from "./useRenderQueue";
 
+const RENDER_SETTINGS_KEY = "hf-studio-render-settings";
+
+interface PersistedRenderSettings {
+  format: "mp4" | "webm" | "mov";
+  quality: "draft" | "standard" | "high";
+  fps: 24 | 30 | 60;
+}
+
+export function getPersistedRenderSettings(): PersistedRenderSettings {
+  try {
+    const raw = localStorage.getItem(RENDER_SETTINGS_KEY);
+    if (raw) {
+      const parsed = JSON.parse(raw);
+      return {
+        format: ["mp4", "webm", "mov"].includes(parsed.format) ? parsed.format : "mp4",
+        quality: ["draft", "standard", "high"].includes(parsed.quality)
+          ? parsed.quality
+          : "standard",
+        fps: [24, 30, 60].includes(parsed.fps) ? parsed.fps : 30,
+      };
+    }
+  } catch {
+    /* ignore */
+  }
+  return { format: "mp4", quality: "standard", fps: 30 };
+}
+
 export interface CompositionDimensions {
   width: number;
   height: number;
@@ -198,10 +225,19 @@ function FormatExportButton({
   isRendering: boolean;
   compositionDimensions?: CompositionDimensions | null;
 }) {
-  const [format, setFormat] = useState<"mp4" | "webm" | "mov">("mp4");
-  const [quality, setQuality] = useState<"draft" | "standard" | "high">("standard");
+  const persisted = getPersistedRenderSettings();
+  const [format, setFormat] = useState<"mp4" | "webm" | "mov">(persisted.format);
+  const [quality, setQuality] = useState<"draft" | "standard" | "high">(persisted.quality);
   const [resolution, setResolution] = useState<ResolutionPreset | "auto">("auto");
-  const [fps, setFps] = useState<24 | 30 | 60>(30);
+  const [fps, setFps] = useState<24 | 30 | 60>(persisted.fps);
+
+  const persistSettings = useCallback((f: typeof format, q: typeof quality, fp: typeof fps) => {
+    try {
+      localStorage.setItem(RENDER_SETTINGS_KEY, JSON.stringify({ format: f, quality: q, fps: fp }));
+    } catch {
+      /* ignore */
+    }
+  }, []);
 
   // MOV (ProRes) is a fixed-quality codec — quality selector has no effect.
   const showQuality = format !== "mov";
@@ -228,7 +264,11 @@ function FormatExportButton({
       {showQuality && (
         <select
           value={quality}
-          onChange={(e) => setQuality(e.target.value as "draft" | "standard" | "high")}
+          onChange={(e) => {
+            const v = e.target.value as "draft" | "standard" | "high";
+            setQuality(v);
+            persistSettings(format, v, fps);
+          }}
           disabled={isRendering}
           title={QUALITY_OPTIONS.find((q) => q.value === quality)?.title}
           className="h-5 px-1 text-[10px] bg-neutral-800 border border-neutral-700 text-neutral-300 outline-none disabled:opacity-50"
@@ -242,7 +282,11 @@ function FormatExportButton({
       )}
       <select
         value={fps}
-        onChange={(e) => setFps(Number(e.target.value) as 24 | 30 | 60)}
+        onChange={(e) => {
+          const v = Number(e.target.value) as 24 | 30 | 60;
+          setFps(v);
+          persistSettings(format, quality, v);
+        }}
         disabled={isRendering}
         title="Frames per second"
         className="h-5 px-1 text-[10px] bg-neutral-800 border border-neutral-700 text-neutral-300 outline-none disabled:opacity-50"
@@ -253,7 +297,11 @@ function FormatExportButton({
       </select>
       <select
         value={format}
-        onChange={(e) => setFormat(e.target.value as "mp4" | "webm" | "mov")}
+        onChange={(e) => {
+          const v = e.target.value as "mp4" | "webm" | "mov";
+          setFormat(v);
+          persistSettings(v, quality, fps);
+        }}
         disabled={isRendering}
         className="h-5 px-1 text-[10px] bg-neutral-800 border border-neutral-700 text-neutral-300 outline-none disabled:opacity-50"
       >

packages/studio/src/components/renders/useRenderQueue.ts

@@ -29,6 +29,8 @@ export interface StartRenderOptions {
   format?: "mp4" | "webm" | "mov";
   /** `"auto"` (default) renders at the composition's authored dimensions. */
   resolution?: ResolutionPreset | "auto";
+  /** Render a specific composition file instead of index.html. */
+  composition?: string;
 }
 
 export function useRenderQueue(projectId: string | null) {
@@ -86,17 +88,25 @@ export function useRenderQueue(projectId: string | null) {
       const quality = opts.quality ?? "standard";
       const format = opts.format ?? "mp4";
       const resolution = opts.resolution;
+      const composition = opts.composition;
 
       const startTime = Date.now();
       // "auto" / undefined means "render at the composition's authored size".
       // Omit the field entirely — sending "auto" would trip the route's
       // enum validation set.
-      const body: { fps: number; quality: string; format: string; resolution?: string } = {
+      const body: {
+        fps: number;
+        quality: string;
+        format: string;
+        resolution?: string;
+        composition?: string;
+      } = {
         fps,
         quality,
         format,
       };
       if (resolution && resolution !== "auto") body.resolution = resolution;
+      if (composition) body.composition = composition;
       let res: Response;
       try {
         res = await fetch(`/api/projects/${projectId}/render`, {