Python 屏幕截图

Question

我正在尝试编写一个程序来使用全局热键获取屏幕截图。下面是相应的代码:

from datetime import datetime
import os
from pynput import keyboard
import pyautogui
import pathlib

def on_activate():
    today = datetime.now()
    d = today.strftime("%Y-%m-%d-%H-%M-%S")
    myScreenshot = pyautogui.screenshot(region=(200,200, 1720, 800))
    time_stamp = '{:%y%d%m}'.format(today)
    fpath = pathlib.Path("C:","Users","Desktop","TestScreenCap", time_stamp)
    if not os.path.exists(fpath):
        os.makedirs(fpath)
    myScreenshot.save(pathlib.Path(fpath,d,".jpg"))

def for_canonical(f):
    return lambda k: f(l.canonical(k))

hotkey = keyboard.HotKey(
    keyboard.HotKey.parse('<ctrl>+<alt>+h'),
    on_activate)
with keyboard.Listener(
        on_press=for_canonical(hotkey.press),
        on_release=for_canonical(hotkey.release)) as l:
    l.join()

错误信息:

Unhandled exception in listener callback
Traceback (most recent call last):
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\PIL\Image.py", line 2138, in save format = EXTENSION[ext]
KeyError: ''

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\_util\__init__.py", line 211, in inner
    return f(self, *args, **kwargs)
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\keyboard\_win32.py", line 280, in _process self.on_press(key)
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\_util\__init__.py", line 127, in inner
    if f(*args) is False:
  File "C:/Users/PycharmProjects/untitled1/123.py", line 18, in <lambda>
    return lambda k: f(l.canonical(k))
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\keyboard\__init__.py", line 182, in press
    self._on_activate()
  File "C:/Users/PycharmProjects/untitled1/123.py", line 15, in on_activate
    myScreenshot.save(pathlib.Path(fpath,d,".jpg"))
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\PIL\Image.py", line 2140, in save
    raise ValueError("unknown file extension: {}".format(ext)) from e
ValueError: unknown file extension: 
Traceback (most recent call last):
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\PIL\Image.py", line 2138, in save
    format = EXTENSION[ext]
KeyError: ''

上面的异常是下面异常的直接原因:

Traceback (most recent call last):
  File "C:/Users/PycharmProjects/untitled1/123.py", line 26, in <module>
    l.join()

  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\_util\__init__.py", line 259, in join
    six.reraise(exc_type, exc_value, exc_traceback)

  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\six.py", line 702, in reraise
    raise value.with_traceback(tb)
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\_util\__init__.py", line 211, in inner
    return f(self, *args, **kwargs)
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\keyboard\_win32.py", line 280, in _process
    self.on_press(key)
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\_util\__init__.py", line 127, in inner
    if f(*args) is False:
  File "C:/Users/PycharmProjects/untitled1/123.py", line 18, in <lambda>
    return lambda k: f(l.canonical(k))
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\pynput\keyboard\__init__.py", line 182, in press
    self._on_activate()
  File "C:/Users/PycharmProjects/untitled1/123.py", line 15, in on_activate
    myScreenshot.save(pathlib.Path(fpath,d,".jpg"))
  File "C:\Users\PycharmProjects\untitled1\venv\lib\site-packages\PIL\Image.py", line 2140, in save
    raise ValueError("unknown file extension: {}".format(ext)) from e
ValueError: unknown file extension:
 

我不知道如何将图像保存到文件夹中。我希望下面的代码不会起作用:

myScreenshot.save(pathlib.Path(fpath,d,".jpg"))

通过一个简单的操作将函数更改为 on_activate，例如:

Print("Hello")

热键脚本完美运行。

我是编程新手，非常感谢任何帮助!

Answer 1

这里是固定代码:

from datetime import datetime
import os
from pynput import keyboard
import pyautogui
import pathlib

def on_activate():
    today = datetime.now()
    d = today.strftime("%Y-%m-%d-%H-%M-%S")
    myScreenshot = pyautogui.screenshot(region=(200,200, 1720, 800))
    time_stamp = '{:%y%d%m}'.format(today)
    fpath = pathlib.Path("C:\\","Users","Desktop","TestScreenCap", time_stamp)
    if not os.path.exists(fpath):
        os.makedirs(fpath)
    myScreenshot.save(pathlib.Path(fpath,d + ".jpg"))

def for_canonical(f):
    return lambda k: f(l.canonical(k))

hotkey = keyboard.HotKey(
    keyboard.HotKey.parse('<ctrl>+<alt>+h'),
    on_activate)
with keyboard.Listener(
        on_press=for_canonical(hotkey.press),
        on_release=for_canonical(hotkey.release)) as l:
    l.join()

问题是您使用的是:

myScreenshot.save(pathlib.Path(fpath,d,".jpg"))

函数 pathlib.Path(fpath,d,".jpg") 将字符串加入 \ 到每个末尾，所以你所在的路径试图保存文件是:

C:Users\Desktop\TestScreenCap\200309\2020-09-03-16-50-20\.jpg

如您所见，文件名是引发异常的扩展名。

只需替换为:myScreenshot.save(pathlib.Path(fpath,d + ".jpg"))

另外一个关于指定路径的问题是C:被解释为Drive，所以当你保存函数的时候，是保存到你程序当前运行的路径，而不是真正的指定路径.要修复此部分，只需将 C: 替换为 C:\\。

阅读您的代码我认为您希望将屏幕截图保存在当前用户桌面中，如果是这样，请替换以下行:fpath = pathlib.Path("C:\\","Users","Desktop""TestScreenCap", time_stamp) 与 fpath = pathlib.Path(os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop'), time_stamp) 并在顶部添加 import os。有了这个，您无需关心路径的正确生成。