生成宽高等比缩略图

做个投票系统，要批量上传照片，用到了缩略图，然后整合了图片处理和文件操作

# coding=gbk'''    python图片处理    @author:fc_lamp    @blog:http://fc-lamp.blog.163.com/'''#!/usr/bin/env python  import os  import os.path  import sys  import Image as image#等比例压缩图片def resizeImg(**args):    args_key = {'ori_img':'','dst_img':'','dst_w':'','dst_h':'','save_q':75}    arg = {}    for key in args_key:        if key in args:            arg[key] = args[key]            im = image.open(arg['ori_img'])    ori_w,ori_h = im.size    widthRatio = heightRatio = None    ratio = 1    if (ori_w and ori_w > arg['dst_w']) or (ori_h and ori_h > arg['dst_h']):        if arg['dst_w'] and ori_w > arg['dst_w']:            widthRatio = float(arg['dst_w']) / ori_w #正确获取小数的方式        if arg['dst_h'] and ori_h > arg['dst_h']:            heightRatio = float(arg['dst_h']) / ori_h        if widthRatio and heightRatio:            if widthRatio < heightRatio:                ratio = widthRatio            else:                ratio = heightRatio        if widthRatio and not heightRatio:            ratio = widthRatio        if heightRatio and not widthRatio:            ratio = heightRatio                    newWidth = int(ori_w * ratio)        newHeight = int(ori_h * ratio)    else:        newWidth = ori_w        newHeight = ori_h            im.resize((newWidth,newHeight),image.ANTIALIAS).save(arg['dst_img'],quality=arg['save_q'])    #image.ANTIALIAS还有如下值：    #NEAREST: use nearest neighbour    #BILINEAR: linear interpolation in a 2x2 environment    #BICUBIC:cubic spline interpolation in a 4x4 environment    #ANTIALIAS:best down-sizing filter  #裁剪压缩图片def clipResizeImg(**args):        args_key = {'ori_img':'','dst_img':'','dst_w':'','dst_h':'','save_q':75}    arg = {}    for key in args_key:        if key in args:            arg[key] = args[key]            im = image.open(arg['ori_img'])    ori_w,ori_h = im.size    dst_scale = float(arg['dst_h']) / arg['dst_w'] #目标高宽比    ori_scale = float(ori_h) / ori_w #原高宽比    if ori_scale >= dst_scale:        #过高        width = ori_w        height = int(width*dst_scale)        x = 0        y = (ori_h - height) / 3            else:        #过宽        height = ori_h        width = int(height*dst_scale)        x = (ori_w - width) / 2        y = 0    #裁剪    box = (x,y,width+x,height+y)    #这里的参数可以这么认为：从某图的(x,y)坐标开始截，截到(width+x,height+y)坐标    #所包围的图像，crop方法与php中的imagecopy方法大为不一样    newIm = im.crop(box)    im = None    #压缩    ratio = float(arg['dst_w']) / width    newWidth = int(width * ratio)    newHeight = int(height * ratio)    newIm.resize((newWidth,newHeight),image.ANTIALIAS).save(arg['dst_img'],quality=arg['save_q'])    #水印(这里仅为图片水印)def waterMark(**args):    args_key = {'ori_img':'','dst_img':'','mark_img':'','water_opt':''}    arg = {}    for key in args_key:        if key in args:            arg[key] = args[key]            im = image.open(arg['ori_img'])    ori_w,ori_h = im.size    mark_im = image.open(arg['mark_img'])    mark_w,mark_h = mark_im.size    option ={'leftup':(0,0),'rightup':(ori_w-mark_w,0),'leftlow':(0,ori_h-mark_h),             'rightlow':(ori_w-mark_w,ori_h-mark_h)             }        im.paste(mark_im,option[arg['water_opt']],mark_im.convert('RGBA'))    im.save(arg['dst_img'])dir=r'F:\2013出游照片精选'for i in os.listdir(dir):    n,ext=os.path.splitext(i)    if ext.lower()=='.jpg':            ori_img = dir+os.sep+i            dst_img  = dir+os.sep+i+'.thumb.jpg'            dst_w = 300#dst_w = 94            dst_h = 300#dst_h = 94            save_q = 100#save_q = 35            clipResizeImg(ori_img=ori_img,dst_img=dst_img,dst_w=dst_w,dst_h=dst_h,save_q = save_q)            print i   '''        #Demon#源图片ori_img = 'D:/tt.jpg'#水印标mark_img = 'D:/mark.png'#水印位置(右下)#water_opt = 'rightlow'#目标图片dst_img = 'D:/python_2.jpg'#目标图片大小dst_w = 300#dst_w = 94dst_h = 300#dst_h = 94#保存的图片质量save_q = 50#save_q = 35#裁剪压缩clipResizeImg(ori_img=ori_img,dst_img=dst_img,dst_w=dst_w,dst_h=dst_h,save_q = save_q)#等比例压缩#resizeImg(ori_img=ori_img,dst_img=dst_img,dst_w=dst_w,dst_h=dst_h,save_q=save_q)#水印#waterMark(ori_img=ori_img,dst_img=dst_img,mark_img=mark_img,water_opt=water_opt)'''