screenshot.py•3.09 kB
import io
import win32gui
import win32ui
import win32api
from PIL import Image
import ctypes
from fastmcp import FastMCP, Image as FastMCPImage
mcp: FastMCP = FastMCP(
name="screencapture",
)
# this was mostly llm generated so if it doesn't work, blame the ai
@mcp.tool("screenshot_window")
async def screenshot_window(hwnd: int) -> str | FastMCPImage:
"""Capture a screenshot of the specified window handle (hwnd). Does not require the window to be visible."""
try:
hwnd = int(hwnd)
if not win32gui.IsWindow(hwnd):
return "Invalid window handle"
# Get window rect
left, top, right, bottom = win32gui.GetWindowRect(hwnd)
width = right - left
height = bottom - top
# Check for valid dimensions
if width <= 0 or height <= 0:
return "Window has invalid dimensions"
# Get window device context
hwndDC = win32gui.GetWindowDC(hwnd)
mfcDC = win32ui.CreateDCFromHandle(hwndDC)
saveDC = mfcDC.CreateCompatibleDC()
saveBitMap = win32ui.CreateBitmap()
saveBitMap.CreateCompatibleBitmap(mfcDC, width, height)
saveDC.SelectObject(saveBitMap)
# Change PrintWindow flags to capture entire window content including child windows
# PW_RENDERFULLCONTENT = 0x00000002
result = ctypes.windll.user32.PrintWindow(hwnd, saveDC.GetSafeHdc(), 2)
# Add a small delay to ensure the content is captured
win32api.Sleep(100)
bmpinfo = saveBitMap.GetInfo()
bmpstr = saveBitMap.GetBitmapBits(True)
# Check if we have valid bitmap data
if not bmpstr or len(bmpstr) <= 0:
return "Failed to capture window content"
img = Image.frombuffer(
"RGB",
(bmpinfo['bmWidth'], bmpinfo['bmHeight']),
bmpstr, 'raw', 'BGRX', 0, 1
)
# Cleanup
win32gui.DeleteObject(saveBitMap.GetHandle())
saveDC.DeleteDC()
mfcDC.DeleteDC()
win32gui.ReleaseDC(hwnd, hwndDC)
if result:
# Preserve aspect ratio when resizing
if width > 0 and height > 0:
target_width = 1024
target_height = int(height * (target_width / width))
# Make sure we don't exceed maximum height
if target_height > 2048:
target_height = 2048
target_width = int(width * (target_height / height))
img = img.resize((target_width, target_height), Image.LANCZOS)
buffer = io.BytesIO()
img.save(buffer, format="PNG")
buffer.seek(0)
return FastMCPImage(data=buffer.read(), format="png")
else:
return "Screenshot may be partial or failed due to permissions"
except Exception as e:
return f"Failed to capture screenshot: {type(e).__name__}: {e}"