python---以不变形的方式调整图片大小

转自
http://www.cnblogs.com/neo-T/p/6477378.html

import os, sysimport cv2#按照指定图像大小调整尺寸def resize_image(image, height, width):     top, bottom, left, right = (0, 0, 0, 0)     #获取图像尺寸     h, w, _ = image.shape     #对于长宽不相等的图片，找到最长的一边     longest_edge = max(h, w)         #计算短边需要增加多上像素宽度使其与长边等长     if h < longest_edge:         dh = longest_edge - h         top = dh // 2         bottom = dh - top     elif w < longest_edge:         dw = longest_edge - w         left = dw // 2         right = dw - left     else:         pass      #RGB颜色     BLACK = [0, 0, 0]     #给图像增加边界，是图片长、宽等长，cv2.BORDER_CONSTANT指定边界颜色由value指定     constant = cv2.copyMakeBorder(image, top , bottom, left, right, cv2.BORDER_CONSTANT, value = BLACK)     #调整图像大小并返回     return cv2.resize(constant, (height, width))def resizeImg(path_name, newpath):         for dir_item in os.listdir(path_name):         #从初始路径开始叠加，合并成可识别的操作路径         full_path = os.path.abspath(os.path.join(path_name, dir_item))         if os.path.isdir(full_path):    #如果是文件夹，继续递归调用             read_path(full_path)         else:   #文件             if dir_item.endswith('.jpg'):                 image = cv2.imread(full_path)                                 image = resize_image(image, 64, 64)                 cv2.imwrite(newpath + '/' + dir_item, image)def main():    # 调整图片大小    f = 'E:/bd/train/val2/23'    fnew = 'E:/bd/train/val3/23'    resizeImg(f, fnew)if __name__ == "__main__":    main()