python 生成 缩略图

make_thumb.py

import os
import Image

#生成node 75x75 缩略图
def make_node_thumb(path):
    base, ext = os.path.splitext(path)
    try:
        im = Image.open(path)
    except IOError:
        print ' in  IOError'
        return

    mode = im.mode
    if mode not in ('L', 'RGB'):
        if mode == 'RGBA':
            # 透明图片需要加白色底
            im.load()
            alpha = im.split()[3]
            bgmask = alpha.point(lambda x: 255-x)
            im = im.convert('RGB')
            # paste(color, box, mask)
            im.paste((255,255,255), None, bgmask)
        else:
            im = im.convert('RGB')

    width, height = im.size
    # 裁剪图片成正方形
    if width > height:
        delta = (width - height) / 2
        box = (delta, 0, width - delta, height)
        region = im.crop(box)
    elif height > width:
        delta = (height - width) / 2
        box = (0, delta, width, height - delta)
        region = im.crop(box)
    else:
        region = im

    filename = base + "_75.jpg"

    thumb = region.resize((75, 75), Image.ANTIALIAS)
    # thumb = im.thumbnail((75,75), Image.ANTIALIAS)
    thumb.save(filename, quality=100) # 默认 JPEG 保存质量是 75, 不太清楚。可选值(0~100)