choose source and arrow for generated videos

web_backend.py

@@ -864,13 +864,14 @@ class Handler(BaseHTTPRequestHandler):
                 input_dir = body["inputDir"]
                 max_angle = float(body.get("maxAngle", 20))
                 duration = float(body.get("durationSeconds", 6))
+                show_arrow = bool(body.get("showArrow", True))
 
                 def worker(job_id):
                     job_root = RESULT_DIR / job_id
                     reset_dir(job_root)
                     output_file = job_root / f"head_extension_{job_id}.mp4"
                     set_job(job_id, message="正在生成 0° 到目标角度的视频。")
-                    output = generate_video(input_dir, output_file, max_angle, duration)
+                    output = generate_video(input_dir, output_file, max_angle, duration, show_arrow)
                     output = Path(output).resolve()
                     return {
                         "video": {