Capture Screen Windows

Screen Capture Skill (Windows)

Capabilities

• Take full screen screenshots.
• Take screenshots of specific application windows (e.g., Browsers like Chrome, Edge, Firefox).
• Get information about the currently active window or list all windows.

Best Practices

⚠️ IMPORTANT: Before taking a window-specific screenshot, ALWAYS list all available windows first to identify the correct window name or title. Window class names and titles can vary, so listing helps ensure you use the correct identifier.

Recommended Workflow:

1. Run python capture-screen-windows/window_info.py list to see all available windows
2. Identify the window by its title or class name from the JSON output
3. Use that title or class name in the screenshot command

Usage

1. Get Window Information (CRITICAL FIRST STEP)

⭐ ALWAYS START HERE when capturing specific windows to avoid errors.

List All Windows (Recommended): Returns a JSON array with all detected windows, including class name, window title, ID, bounds, and area.

python capture-screen-windows/window_info.py list

Example output:

[
  {
    "app": "Chrome_WidgetWin_1",
    "title": "GitHub - example/repo - Google Chrome",
    "id": 12345,
    "bounds": {"X": 0, "Y": 0, "Width": 1920, "Height": 1080},
    "area": 2073600
  },
  {
    "app": "CabinetWClass",
    "title": "Documents",
    "id": 67890,
    "bounds": {"X": 100, "Y": 100, "Width": 800, "Height": 600},
    "area": 480000
  }
]

Get Active Window Info: Returns JSON with info about the currently active (frontmost) window.

python capture-screen-windows/window_info.py active

2. Take Screenshots

Full Screen Screenshot

Run the python script with the full command:

python capture-screen-windows/screenshot.py full <output_path>

Example:

python capture-screen-windows/screenshot.py full C:\temp\my_screen.png

Window Screenshot

Run the python script with the window command, specifying the window title or class name and output path.

⚠️ Important: Use the window title or class name from window_info.py list output. The script supports fuzzy matching (searches in both title and class name).

python capture-screen-windows/screenshot.py window "<Window Title or Class>" <output_path>

Examples:

python capture-screen-windows/screenshot.py window "Chrome" C:\temp\chrome_window.png
python capture-screen-windows/screenshot.py window "Visual Studio Code" C:\temp\vscode_window.png
python capture-screen-windows/screenshot.py window "Command Prompt" C:\temp\cmd_window.png

List Windows (Human Readable)

To see a formatted table of windows for quick reference:

python capture-screen-windows/screenshot.py list

Dependencies & Requirements

• Windows OS
• Python 3
• Required packages:
  • pywin32 - For Windows API access
  • pillow - For image capture and manipulation

Installation

Install dependencies using pip:

pip install pywin32 pillow

Technical Details

Window Identification

• Uses Win32 API (win32gui) to enumerate windows
• Captures window class names and titles
• Filters out invisible windows
• Sorts by area to prioritize main windows over dialogs

Screenshot Method

• Full screen: Uses PIL.ImageGrab.grab()
• Window capture: Uses PIL.ImageGrab.grab(bbox=...) with window coordinates
• Brings target window to foreground before capture
• Outputs high-quality PNG images

Troubleshooting

Permission Issues

Some windows (especially system windows) may require elevated permissions. Run your terminal as Administrator if you encounter permission errors.

Import Errors

If you see ImportError: No module named 'win32gui', install pywin32:

pip install pywin32

After installation, you may need to run:

python -m pywin32_postinstall -install

Window Not Found

If a window isn't being captured:

1. Ensure the window is visible (not minimized)
2. Check the exact title using the list command
3. Try using a partial match from the title
4. Try using the window class name instead