使用threading.Timer，使用Python以固定間隔截取屏幕截圖

Question

我正在用pyGTK編寫一個簡單的GUI應用程序，以固定的間隔拍攝桌面截圖。 為了安排鏡頭我使用threading.Timer類並拍攝我使用os.system調用scrot。

當我單擊開始截屏按鈕時，將調用GlapseMain.startScreenshots方法。 當我單擊停止截屏按鈕時，將調用GlapseMain.stopScreenshots方法。

事情是在GTK應用程序運行時，雖然它應該沒有截屏。 當我點擊關閉按鈕時，它會開始無限期地截取屏幕截圖。

這是我的代碼：

#!/usr/bin/env python
# -*- coding: utf8  -*-

import threading
import os

class GlapseMain:

def __init__(self):
    self.outputDir = os.getenv('HOME')
    self.quality = 80
    self.interval = 10
    self.numDigits = 15
    self.currentShot = 0

def startScreenshots(self, output, quality, interval):
    print 'Starting taking screenshots...'
    print 'Output folder: ' + str(output)
    print 'Quality: ' + str(quality)
    print 'Interval: ' + str(interval)

    # Update attributes
    self.outputDir = output
    self.quality = quality
    self.interval = interval
    self.currentShot = 0

    # Create timer (first screenshot scheduled 1s ahead)
    self.timer = threading.Timer(1.0, self._takeScreenshot)
    self.timer.start()


def stopScreenshots(self):
    print 'Stopped taking screenshots.'

    self.timer.cancel()


def _takeScreenshot(self):
    # Build scrot command
    fileNumber = str(self.currentShot)
    fileNumber = fileNumber.zfill(self.numDigits - len(fileNumber))
    fileName = 'scr-' + fileNumber + '.jpg'

    command = 'scrot -q ' + str(self.quality) + ' ' + self.outputDir + os.sep + fileName

    print 'Taking screenshot: ' + command + '...'

    os.system(command)

    # Schedule next screenshot
    self.currentShot = self.currentShot + 1
    self.timer = threading.Timer(self.interval, self._takeScreenshot)
    self.timer.start()

我的輸出看起來像這樣：

Starting taking screenshots...
Output folder: /home/david/glapse-screens
Quality: 80.0
Interval: 2.0
Stopped taking screenshots.
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000000.jpg...
Closing gLapse...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000001.jpg...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000002.jpg...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000003.jpg...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000004.jpg...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000005.jpg...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000006.jpg...
Taking screenshot: scrot -q 80.0 /home/david/glapse-screens/scr-00000000000007.jpg...

希望你能幫助我，非常感謝你。

編輯：

我已經改變了方法，現在我正在使用線程：

def startScreenshots(self, output, quality, interval):
    print 'Starting taking screenshots...'
    print 'Output folder: ' + str(output)
    print 'Quality: ' + str(quality)
    print 'Interval: ' + str(interval)

    # Update attributes
    self.outputDir = output
    self.quality = quality
    self.interval = interval
    self.currentShot = 0

    # Start a thread to take screenshots
    self.done = False
    self.thread = threading.Thread(target=self._takeScreenshot)
    self.thread.start()

def stopScreenshots(self):
    print 'Stopped taking screenshots.'
    self.done = True
    self.thread.join()


def _takeScreenshot(self):
    # Run until we're done
    while not self.done:
        # Build scrot command
        fileNumber = str(self.currentShot)
        fileNumber = fileNumber.zfill(self.numDigits - len(fileNumber))
        fileName = 'scr-' + fileNumber + '.jpg'

        command = 'scrot -q ' + str(self.quality) + ' ' + self.outputDir + os.sep + fileName

        print 'Taking screenshot: ' + command + '...'

        os.system(command)

        # Schedule next screenshot
        print 'Scheduling next screenshot...'
        self.currentShot = self.currentShot + 1
        time.sleep(self.interval)

它打印消息但不執行os.system指令直到我按下停止按鈕。

Answer 1

回應：

你還需要打電話

gtk.gdk.threads_init()

如果你想要帶有gtk的線程，則在調用gtk.main（）之前

---

讓_takeScreenshot（）改為使用while循環，不要為下一個屏幕截圖啟動新線程。 你已經有了一個工作線程，例如

您還需要一個Thread而不是Timer

def _takeScreenshot(self):
    while self.notDone:
         # take screen shot
         # ..
         time.sleep(self.interval)

然后在你的取消方法做類似的事情：

def stopScreenshots(self):
    self.notDone = False
    self.timer.join() # wait for thread to finish