python(PIL)图像处理(等比例压缩、裁剪压缩) 缩略(水印)图详解编程语言

#coding:utf-8 
''' 
    python图片处理 
    @author:fc_lamp 
    @blog:http://fc-lamp.blog.163.com/ 
''' 
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']) 
     
 
         
#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 = 94 
dst_h = 94 
#保存的图片质量 
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)