python使用PIL实现多张图片垂直合并

# coding: utf-8 
# image_merge.py 
# 图片垂直合并 
# http://www.redicecn.com 
# redice@163.com 
 
import os 
import Image 
 
def image_resize(img, size=(1500, 1100)): 
  """调整图片大小 
  """ 
  try: 
    if img.mode not in ('L', 'RGB'): 
      img = img.convert('RGB') 
    img = img.resize(size) 
  except Exception, e: 
    pass 
  return img 
 
def image_merge(images, output_dir='output', output_name='merge.jpg', \ 
        restriction_max_width=None, restriction_max_height=None): 
  """垂直合并多张图片 
  images - 要合并的图片路径列表 
  ouput_dir - 输出路径 
  output_name - 输出文件名 
  restriction_max_width - 限制合并后的图片最大宽度，如果超过将等比缩小 
  restriction_max_height - 限制合并后的图片最大高度，如果超过将等比缩小 
  """ 
  max_width = 0 
  total_height = 0 
  # 计算合成后图片的宽度（以最宽的为准）和高度 
  for img_path in images: 
    if os.path.exists(img_path): 
      img = Image.open(img_path) 
      width, height = img.size 
      if width > max_width: 
        max_width = width 
      total_height += height 
 
  # 产生一张空白图 
  new_img = Image.new('RGB', (max_width, total_height), 255) 
  # 合并 
  x = y = 0 
  for img_path in images: 
    if os.path.exists(img_path): 
      img = Image.open(img_path) 
      width, height = img.size 
      new_img.paste(img, (x, y)) 
      y += height 
 
  if restriction_max_width and max_width >= restriction_max_width: 
    # 如果宽带超过限制 
    # 等比例缩小 
    ratio = restriction_max_height / float(max_width) 
    max_width = restriction_max_width 
    total_height = int(total_height * ratio) 
    new_img = image_resize(new_img, size=(max_width, total_height)) 
 
  if restriction_max_height and total_height >= restriction_max_height: 
    # 如果高度超过限制 
    # 等比例缩小 
    ratio = restriction_max_height / float(total_height) 
    max_width = int(max_width * ratio) 
    total_height = restriction_max_height 
    new_img = image_resize(new_img, size=(max_width, total_height)) 
   
  if not os.path.exists(output_dir): 
    os.makedirs(output_dir) 
  save_path = '%s/%s' % (output_dir, output_name) 
  new_img.save(save_path) 
  return save_path 
   
if __name__ == '__main__': 
  image_merge(images=['900-000-000-0501a_b.jpg', '900-000-000-0501b_b.JPG', '1216005237382a_b.jpg'])