feat: improve subject conversion composer

api/main.py

@@ -4706,6 +4706,60 @@ def add_manual_frame(job_id: str, t: float) -> Job:
     return job
 
 
+@app.post("/jobs/{job_id}/frames/upload", response_model=Job)
+async def upload_reference_frame(job_id: str, file: UploadFile = File(...)) -> Job:
+    """把用户拖入的图片保存为一张参考帧，供转换层和主体生成复用。"""
+    job = JOBS.get(job_id)
+    if not job:
+        raise HTTPException(404, "job not found")
+    content_type = (file.content_type or "").lower()
+    suffix = Path(file.filename or "").suffix.lower()
+    if content_type and not content_type.startswith("image/"):
+        raise HTTPException(400, "only image uploads are supported")
+    if not content_type and suffix not in {".jpg", ".jpeg", ".png", ".webp", ".bmp"}:
+        raise HTTPException(400, "only image uploads are supported")
+
+    d = job_dir(job_id)
+    frames_dir = d / "frames"
+    frames_dir.mkdir(parents=True, exist_ok=True)
+    next_idx = max((f.index for f in job.frames), default=-1) + 1
+    tmp = frames_dir / f"{next_idx:03d}.upload"
+    out = frames_dir / f"{next_idx:03d}.jpg"
+    try:
+        await _save_upload_to_path(file, tmp)
+        with Image.open(tmp) as raw:
+            img = ImageOps.exif_transpose(raw).convert("RGB")
+            img.thumbnail((2400, 2400), Image.LANCZOS)
+            img.save(out, "JPEG", quality=92, optimize=True)
+    except Exception as e:
+        try:
+            out.unlink()
+        except OSError:
+            pass
+        raise HTTPException(400, f"reference image upload failed: {e}")
+    finally:
+        try:
+            tmp.unlink()
+        except OSError:
+            pass
+
+    next_timestamp = max((float(f.timestamp) for f in job.frames), default=float(job.duration or 0)) + 0.01
+    new_frame = KeyFrame(
+        index=next_idx,
+        timestamp=round(next_timestamp, 2),
+        url=f"/jobs/{job_id}/frames/{next_idx}.jpg",
+        description={
+            "scene": "用户拖入的转换层参考图",
+            "objects": [],
+            "style": "uploaded reference image",
+            "suggested_prompt": "",
+        },
+    )
+    merged = sorted(list(job.frames) + [new_frame], key=lambda f: f.timestamp)
+    update(job, frames=merged, message=f"已加入上传参考图，共 {len(merged)} 张")
+    return job
+
+
 @app.get("/jobs/{job_id}", response_model=Job)
 def get_job(job_id: str) -> Job:
     job = JOBS.get(job_id)