python pygame blit。获取要显示的图像

我正在尝试让我的网络摄像头通过 pygame 显示视频。这是代码:

# import the relevant libraries 
import time 
import pygame 
import pygame.camera 
from pygame.locals import * 
# this is where one sets how long the script 
# sleeps for, between frames.sleeptime__in_seconds = 0.05 
# initialise the display window 
pygame.init() 
pygame.camera.init() 
 
screen = pygame.display.set_mode((640, 480), 0, 32) 
 
# set up a camera object 
cam = pygame.camera.Camera(0) 
# start the camera 
cam.start() 
 
while 1: 
 
    # sleep between every frame 
    time.sleep( 10 ) 
    # fetch the camera image 
    image = cam.get_image() 
    # blank out the screen 
    screen.fill((0,0,2)) 
    # copy the camera image to the screen 
    screen.blit( image, ( 0, 0 ) ) 
    # update the screen to show the latest screen image 
    pygame.display.update() 

当我尝试这个时，我从 screen.blit( image, ( 0, 0 ) ) 部分得到一个错误

Traceback (most recent call last): 
  File "C:\Python32\src\webcam.py", line 28, in <module> 
    screen.blit( image, ( 0, 0 ) ) 
TypeError: argument 1 must be pygame.Surface, not None 

我想这是因为我没有将图像转换成任何适用于 pygame 的图像，但我不知道。

如有任何帮助，我们将不胜感激。谢谢。

-亚历克斯

好的，这是新代码: 这一个有效，因为它将图片保存到当前文件夹。弄清楚为什么最后一个有效。虽然屏幕仍然是黑色的=\

# import the relevant libraries 
import time 
import pygame 
import pygame.camera 
from pygame.locals import * 
# this is where one sets how long the script 
# sleeps for, between frames.sleeptime__in_seconds = 0.05 
# initialise the display window 
pygame.init() 
pygame.camera.init() 
# set up a camera object 
size = (640,480) 
screen = pygame.display.set_mode(size,0) 
 
 
surface = pygame.surface.Surface(size,0,screen) 
 
cam = pygame.camera.Camera(0,size) 
# start the camera 
cam.start() 
 
while 1: 
 
    # sleep between every frame 
    time.sleep( 10 ) 
    # fetch the camera image 
    pic = cam.get_image(surface) 
    # blank out the screen 
    #screen.fill((0,0,0)) 
    # copy the camera image to the screen 
    screen.blit(pic,(0,0)) 
    # update the screen to show the latest screen image 
    p=("outimage.jpg") 
 
    pygame.image.save(surface,p) 
    pygame.display.update() 

请您参考如下方法:

尝试像这样创建一个相机。

cam = pygame.camera.Camera(camlist[0],(640,480)) 

这就是在 this page 上完成的方式pygame 文档。

查看 API page对于 pygame.camera，我发现了两件事可能会有帮助。首先，

Pygame currently supports only Linux and v4l2 cameras.

EXPERIMENTAL!: This api may change or disappear in later pygame releases. If you use this, your code will very likely break with the next pygame release.

当想知道为什么这出人意料地失败时，请记住这一点。

更乐观一点...您可以尝试调用 camera.get_raw() 并打印结果。它应该是带有原始图像数据的字符串。如果您收到空字符串、None 或一些无意义的文本:请在此处与我们分享。它会告诉您是否从相机中获取了任何信息。

Gets an image from a camera as a string in the native pixelformat of the camera. Useful for integration with other libraries.