python使用pil进行图像处理(等比例压缩、裁剪)实例代码

>>>from PIL import Image>>>im = Image.open('*.jpg')   # 打开一张RGB图像>>>im_bands = im.getbands() # 获取RGB三个波段>>>len(im_bands)>>>print im_bands[0,1,2]     # 输出RGB三个值

>>> im.mode

① 1：1位像素，表示黑和白，但是存储的时候每个像素存储为8bit。② L：8位像素，表示黑和白。③ P：8位像素，使用调色板映射到其他模式。④ RGB：3x8位像素，为真彩色。⑤ RGBA：4x8位像素，有透明通道的真彩色。⑥ CMYK：4x8位像素，颜色分离。⑦ YCbCr：3x8位像素，彩色视频格式。⑧ I：32位整型像素。⑨ F：32位浮点型像素。

>>> im.size()

>>> im.info() # 返回值为字典对象

>>> from PIL import Image >>> im = Image.open('*.jpg')>>> im.size>>> im_resize = im.resize((256,256)) #default 情况下是NEAREST插值方法>>> im_resize0 = im.resize((256,256), Image.BILINEAR)>>> im_resize0.size>>> im_resize1 = im.resize((256,256), Image.BICUBIC)>>> im_resize2 = im.resize((256,256), Image.ANTIALIAS)

#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 = 94dst_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)