Taking Screenshots Using Python & PyQt

Taking screenshots is a common feature in many desktop applications, whether for capturing content, providing feedback, or documenting issues. PyQt, a set of Python bindings for the Qt libraries, allows you to create rich desktop applications with a native look and feel. In this comprehensive guide, we'll walk you through creating a PyQt application to capture and save screenshots.

Prerequisites

Before we start coding, ensure you have Python installed on your system. Additionally, you need to install PyQt5, which you can do using pip:

pip install PyQt5

Setting Up the Project

Start by creating a new Python script file, for example, screenshot_app.py. We will build our application step by step.

Importing Required Libraries

We need to import the essential modules from PyQt5 to create our GUI and handle the screenshot functionality.

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QPushButton, QLabel, QFileDialog
from PyQt5.QtGui import QPixmap, QScreen
from PyQt5.QtCore import Qt

Designing the Main Window

We'll design a simple window that includes a button to capture the screenshot and a label to display the captured image.

class ScreenshotApp(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Screenshot App')
        self.setGeometry(100, 100, 800, 600)

        layout = QVBoxLayout()

        self.label = QLabel('Screenshot will appear here', self)
        self.label.setAlignment(Qt.AlignCenter)
        layout.addWidget(self.label)

        self.button = QPushButton('Take Screenshot', self)
        self.button.clicked.connect(self.take_screenshot)
        layout.addWidget(self.button)

        self.setLayout(layout)

Explanation of the UI Design

• Window Title and Size: The self.setWindowTitle sets the title of the window, and self.setGeometry sets the position and size of the window.

• Layout: We use a QVBoxLayout to arrange widgets vertically.

• Label: A QLabel is used to display the screenshot. It initially shows a placeholder text.

• Button: A QPushButton is used to trigger the screenshot capture. The clicked signal is connected to the take_screenshot method.

Implementing the Screenshot Functionality

Next, we'll implement the functionality to capture and save screenshots.

def take_screenshot(self):
    screen = QApplication.primaryScreen()
    screenshot = screen.grabWindow(0)
    self.label.setPixmap(screenshot.scaled(self.label.size(), Qt.KeepAspectRatio))

    # Save the screenshot
    file_path, _ = QFileDialog.getSaveFileName(self, "Save Screenshot", "", "PNG Files (*.png);;All Files (*)")
    if file_path:
        screenshot.save(file_path, 'png')

Explanation of the Screenshot Functionality

• Capture Screen: QApplication.primaryScreen().grabWindow(0) captures the entire screen.

• Display Screenshot: The captured screenshot is displayed in the QLabel using setPixmap.

• Save Screenshot: A QFileDialog prompts the user to choose a location and filename to save the screenshot. The screenshot is saved as a PNG file.

Putting It All Together

Combine the UI design and screenshot functionality into a complete PyQt application.

class ScreenshotApp(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Screenshot App')
        self.setGeometry(100, 100, 800, 600)

        layout = QVBoxLayout()

        self.label = QLabel('Screenshot will appear here', self)
        self.label.setAlignment(Qt.AlignCenter)
        layout.addWidget(self.label)

        self.button = QPushButton('Take Screenshot', self)
        self.button.clicked.connect(self.take_screenshot)
        layout.addWidget(self.button)

        self.setLayout(layout)

    def take_screenshot(self):
        screen = QApplication.primaryScreen()
        screenshot = screen.grabWindow(0)
        self.label.setPixmap(screenshot.scaled(self.label.size(), Qt.KeepAspectRatio))

        # Save the screenshot
        file_path, _ = QFileDialog.getSaveFileName(self, "Save Screenshot", "", "PNG Files (*.png);;All Files (*)")
        if file_path:
            screenshot.save(file_path, 'png')

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = ScreenshotApp()
    window.show()
    sys.exit(app.exec_())

Running the Application

Save the script and run it using Python:

python screenshot_app.py

This command opens a window with a button labeled "Take Screenshot." When you click the button, the application captures the current screen, displays the screenshot in the window, and prompts you to save the screenshot as a PNG file.

• Region Capture: Allow users to select a specific region of the screen to capture.

• Timestamp Naming: Automatically name the screenshot files with the current timestamp.

• Image Formats: Support saving screenshots in different image formats (e.g., JPEG, BMP).

Additional Steps for macOS

On macOS, applications require explicit permission to capture the screen. To grant this permission:

1. Run the Application: Run your PyQt application once.

2. System Preferences: Go to System Preferences > Security & Privacy > Privacy tab.

3. Screen Recording: In the left-hand sidebar, select Screen Recording.

4. Add Your Application: Click the lock icon to make changes, and add your terminal or IDE to the list by clicking the + button and selecting the appropriate application.

Using the above I have created a tracker for our company.