Python 图片尺寸缩放的4种方式

最近由于网站对图片尺寸的需要，用python写了个小脚本，方便进行图片尺寸的一些调整，特记录如下：

# coding=utf-8import Imageimport shutilimport osclass Graphics:    infile = 'D:\\myimg.jpg'    outfile = 'D:\\adjust_img.jpg'    @classmethod    def fixed_size(cls, width, height):        """按照固定尺寸处理图片"""        im = Image.open(cls.infile)        out = im.resize((width, height),Image.ANTIALIAS)        out.save(cls.outfile)    @classmethod    def resize_by_width(cls, w_divide_h):        """按照宽度进行所需比例缩放"""        im = Image.open(cls.infile)        (x, y) = im.size         x_s = x        y_s = x/w_divide_h        out = im.resize((x_s, y_s), Image.ANTIALIAS)         out.save(cls.outfile)    @classmethod    def resize_by_height(cls, w_divide_h):        """按照高度进行所需比例缩放"""        im = Image.open(cls.infile)        (x, y) = im.size         x_s = y*w_divide_h        y_s = y        out = im.resize((x_s, y_s), Image.ANTIALIAS)         out.save(cls.outfile)    @classmethod    def resize_by_size(cls, size):        """按照生成图片文件大小进行处理(单位KB)"""        size *= 1024        im = Image.open(cls.infile)        size_tmp = os.path.getsize(cls.infile)        q = 100        while size_tmp > size and q > 0:            print q            out = im.resize(im.size, Image.ANTIALIAS)            out.save(cls.outfile, quality=q)            size_tmp = os.path.getsize(cls.outfile)            q -= 5        if q == 100:            shutil.copy(cls.infile, cls.outfile)    @classmethod    def cut_by_ratio(cls, width, height):        """按照图片长宽比进行分割"""        im = Image.open(cls.infile)        width = float(width)        height = float(height)        (x, y) = im.size        if width > height:            region = (0, int((y-(y * (height / width)))/2), x, int((y+(y * (height / width)))/2))        elif width < height:            region = (int((x-(x * (width / height)))/2), 0, int((x+(x * (width / height)))/2), y)        else:            region = (0, 0, x, y)        #裁切图片        crop_img = im.crop(region)        #保存裁切后的图片        crop_img.save(cls.outfile)