Saves icons for open X windows to a folder

save_open_x_window_icons.py

"""Saves icons for open X windows to a folder.
Pypanel inspired me, by showing that Python can get icons with Xlib.
This does that in a more simple and uses PIL to save them too :) 
"""
from PIL import Image
from Xlib import X, display, error, Xatom

DIRECTORY = "/home/user/icons/"


d = display.Display()
root = d.screen().root
DISPLAY_ICON = d.intern_atom("_NET_WM_ICON")


def get_icon(window_object):
    """For an X Window, return largest icon as PIL image if exists"""
    icon = None
    # try to get the raw icon data for the window:
    icon_data = window_object.get_full_property(DISPLAY_ICON, 0)
    if icon_data:  # if there is an icon data to be found...
        icon_data = icon_data.value
        """ The value is a list of numbers, from the spec:
        "_NET_WM_ICON CARDINAL[][2+n]/32
        This is an array of possible icons for the client."
        ...
        "This is an array of 32bit packed CARDINAL ARGB with high byte 
        being A, low byte being B. The first two cardinals are width,
        height. Data is in rows, left to right and top to bottom." - 
        https://specifications.freedesktop.org/wm-spec/wm-spec-1.3.html 
        """
        index = 0  # the current position, of reading icon_data
        # while there is icon data to process:
        while index < len(icon_data):
            # we calculate where the data is,
            # the icon width and height are at the start:
            width = icon_data[index]
            index += 1
            height = icon_data[index]
            index += 1
            # fianlly, the pixel data is at the end:
            icon_data_end = width * height + index

            # get the icon data:
            icon_data_pixels = icon_data[index:icon_data_end]
            index = icon_data_end

        # create an image from the last icon we found:
        pixels = icon_data_pixels.tobytes()
        size = (width, height)
        icon = Image.frombuffer("RGBA", size, pixels, "raw", "BGRA", 0, 1)
    return icon


def get_windows():
    """Returns dict of X window's with id's as the keys,
    containing a name, object, and icon if exists"""

    window_info = {}

    windows = root.get_full_property(
        d.intern_atom("_NET_CLIENT_LIST"), Xatom.WINDOW
    ).value

    for w in windows:
        try:
            window = d.create_resource_object("window", w)
            window_name = window.get_wm_name()
            window_info[w] = dict(
                name=window_name, window=window, icon=get_icon(window)
            )
        except error.BadWindow:
            pass  # Windows can be closed while looping
    return window_info


def safe_filename(unsafe_filename):
    safe_charecters = (".", "_")
    a_little_safer_filename = unsafe_filename.replace(" ", "_")
    return "".join(
        c for c in a_little_safer_filename if c.isalnum() or c in safe_charecters
    ).rstrip()


windows = get_windows()
for window_id in windows:
    window = windows[window_id]
    if window["icon"]:
        name = window["name"]
        if len(name) < 1:
            name = str(window_id)
        window["icon"].save(f"{DIRECTORY}{safe_filename(name)}.png")