import cv2
import time

# 打开摄像头
cap = cv2.VideoCapture(0, cv2.CAP_DSHOW)

# 设置摄像头帧率为30
cap.set(cv2.CAP_PROP_FPS, 35)

# 设置摄像头图像大小为640x480
cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
cap.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc('M', 'J', 'P', 'G'))

# 检查摄像头是否成功打开
if not cap.isOpened():
    print("Error: Could not open camera.")
    exit()

# 定义一个计时器
start_time = time.time()
frame_counter = 0
fps = 0
while True:
    # 读取一帧图像
    ret, frame = cap.read()

    if not ret:
        print("Error: Could not read frame.")
        break

    # 计算帧率
    frame_counter += 1
    elapsed_time = time.time() - start_time
    if elapsed_time > 1:
        fps = frame_counter / elapsed_time
        start_time = time.time()
        frame_counter = 0

    # 在图像上显示帧率
    fps_text = f"FPS: {round(fps, 2)}"
    print(fps_text)
    cv2.putText(frame, fps_text, (10, 30), cv2.FONT_HERSHEY_SIMPLEX, 1, (255, 255, 255), 2)

    # 显示图像
    cv2.imshow("Frame", frame)

    # 检查是否按下了q键，如果是则退出循环
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# 释放摄像头并关闭所有窗口
cap.release()
cv2.destroyAllWindows()