bgchanger.py

#!/usr/bin/env python

import gconf, os, time, pynotify
from PIL import Image 

pynotify.init("BgChanger")

DEFAULTWPDIR = "/usr/share/backgrounds"
NTITLE = "Up Next..." 

class BgChanger:
    """Background changer for Gnome Desktop,
scan image in specified directory and applied those images
as wallpaper via gconf."""

    def __init__(self):
        "init bgchanger set base directory"
        self.gcHnd = gconf.client_get_default()
        self.baseDir = DEFAULTWPDIR
        self.timeout = 1
        self.cursor = 0;
        self.res_default = [1280,1280]
        self.cacheDir = os.path.expanduser("~/.cache")
        self.notif = None
        self.startup = True
        self.images = None

    def __resize(self, filename, create_thumb = False):
        "image resizer, final image stored in .cache folder"
        original = filename
        img = Image.open(filename)
        if create_thumb:
            x, y = [100, 100]
        else:
            x, y = self.res_default
        x0, y0 = img.size
        if x0 > x: y0 = max(x * y0 / x0, 1); x0 = x
        if y0 > y: x0 = max(y * x0 / y0, 1); y0 = y
        if (x0,y0) == img.size: return filename
        im = img.resize([x0,y0],Image.ANTIALIAS)
        if create_thumb:
            filename = os.path.join(self.cacheDir,"thumb.png")
        else:
            filename = os.path.join(self.cacheDir, "walpaper.png")
        try:
            im.save(filename)
        except:
            filename = original
        return filename
        
    def __scanImage(self, ext = [".jpg", ".png"]):
        "directory scanner, create images list from specified directory"
        temp = [os.path.normcase(f) for f in os.listdir(self.baseDir)]
        return [os.path.join(self.baseDir, f) for f in temp
                if os.path.splitext(f)[1] in ext]


##TODO:GUI to queue image and set timer
    def __queueImage(self, image):
        "queue image file"
        self.images.append(image)

    def __setTimer(self, timeout = 10):
        "set timeout for each background to change, timeout in minute"
        self.timeout = timeout

    def __setWallpaper(self):
        "change the wallpaper"
        picture_folder = self.gcHnd.get_string("/desktop/gnome/background/picture_folder")
        if picture_folder != self.baseDir:
            if picture_folder == None:
                self.gcHnd.set_string("/desktop/gnome/background/picture_folder", DEFAULTWPDIR)
                self.baseDir = DEFAULTWPDIR
            else:
                self.baseDir = picture_folder
            self.images = self.__scanImage()
            self.cursor = 0
        self.timeout = self.gcHnd.get_int("/desktop/gnome/background/timeout")
        if self.timeout == 0:
            self.gcHnd.set_int("/desktop/gnome/background/timeout", 1)
            self.timeout = 1
        if self.images == None:
            self.images = self.__scanImage()
        current = self.gcHnd.get_string("/desktop/gnome/background/picture_filename")
        if (current in self.images) and self.startup:
            self.cursor = self.images.index(current)
            self.startup = False
        else:
            self.gcHnd.set_string("/desktop/gnome/background/picture_filename", 
                                  self.__resize(self.images[self.cursor]))
        self.cursor = self.cursor + 1
        if self.cursor == len(self.images): self.cursor = 0
        self.__notifyNext()

    def __notifyNext(self):
        "use pynotify to tell user which wallpaper will be used next"
        BODY = "%s\n%s" % (self.images[self.cursor], "in %d minute(s)" % self.timeout)
        if self.notif == None:
            self.notif = pynotify.Notification(NTITLE, BODY, self.__resize(self.images[self.cursor], True))
        else:
            self.notif.update(NTITLE, BODY, self.__resize(self.images[self.cursor], True))
        self.notif.show()

    def run(self):
        "setup and run the daemon"
        while 1:
            self.__setWallpaper()
            time.sleep(self.timeout * 60)

if __name__ == "__main__":
    gen = BgChanger()
    gen.run()