python生成指定尺寸的缩略图详解编程语言

python生成指定尺寸的缩略图，先对图片进行缩小，然后进行裁剪，直到生成规定的尺寸

def MakeThumb(path, sizes=(75, 32, 16)): 
    """ 
    缩略图生成程序 by Neil Chen 
    sizes 参数传递要生成的尺寸，可以生成多种尺寸 
    """ 
    base, ext = os.path.splitext(path) 
    try: 
        im = Image.open(path) 
    except IOError: 
        return 
    mode = im.mode 
    if mode not in ('L', 'RGB'): 
        if mode == 'RGBA': 
            # 透明图片需要加白色底 
            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 
    if width == height: 
        region = im 
    else: 
        if width > height: 
            delta = (width - height)/2 
            box = (delta, 0, delta+height, height) 
        else: 
            delta = (height - width)/2 
            box = (0, delta, width, delta+width) 
        region = im.crop(box) 
  
    for size in sizes: 
        filename = base + "_" + "%sx%s" % (str(size), str(size)) + ".jpg" 
        thumb = region.resize((size,size), 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)