python使用PIL缩放网络图片并保存的方法

本文实例讲述了python使用PIL缩放网络图片并保存的方法。分享给大家供大家参考。具体实现方法如下：

    ''' tk_image_view_url_io_resize.py
    display an image from a URL using Tkinter, PIL and data_stream
    also resize the web image to fit a certain size display widget
    retaining its aspect ratio
    Pil facilitates resizing and allows file formats other then gif
    tested with Python27 and Python33 by vegaseat 18mar2013
    '''
    import io
    from PIL import Image, ImageTk
    try:
      # Python2
      import Tkinter as tk
      from urllib2 import urlopen
    except ImportError:
      # Python3
      import tkinter as tk
      from urllib.request import urlopen
    def resize(w, h, w_box, h_box, pil_image):
      '''
      resize a pil_image object so it will fit into
      a box of size w_box times h_box, but retain aspect ratio
      '''
      f1 = 1.0*w_box/w # 1.0 forces float division in Python2
      f2 = 1.0*h_box/h
      factor = min([f1, f2])
      #print(f1, f2, factor) # test
      # use best down-sizing filter
      width = int(w*factor)
      height = int(h*factor)
      return pil_image.resize((width, height), Image.ANTIALIAS)
    root = tk.Tk()
    # size of image display box you want
    w_box = 400
    h_box = 350
    # find yourself a picture on an internet web page you like
    # (right click on the picture, under properties copy the address)
    # a larger (1600 x 1200) picture from the internet
    # url name is long, so split it
    url1 = "http://freeflowerpictures.net/image/flowers/petunia/"
    url2 = "petunia-flower.jpg"
    url = url1 + url2
    image_bytes = urlopen(url).read()
    # internal data file
    data_stream = io.BytesIO(image_bytes)
    # open as a PIL image object
    pil_image = Image.open(data_stream)
    # get the size of the image
    w, h = pil_image.size
    # resize the image so it retains its aspect ration
    # but fits into the specified display box
    pil_image_resized = resize(w, h, w_box, h_box, pil_image)
    # optionally show resized image info ...
    # get the size of the resized image
    wr, hr = pil_image_resized.size
    # split off image file name
    fname = url.split('/')[-1]
    sf = "resized {} ({}x{})".format(fname, wr, hr)
    root.title(sf)
    # convert PIL image object to Tkinter PhotoImage object
    tk_image = ImageTk.PhotoImage(pil_image_resized)
    # put the image on a widget the size of the specified display box
    label = tk.Label(root, image=tk_image, width=w_box, height=h_box)
    label.pack(padx=5, pady=5)
    root.mainloop()

希望本文所述对大家的Python程序设计有所帮助。