没什么技术含量，留着以后复用

import cv2

def clip_resize(src_path,dest_path,dest_width,dest_height):
    """
    # 按目标比例剪裁图片
    # 如果宽了，就保持高度，反之，保持宽度
    # 最后缩放到目标尺寸
    :param src_path:源图片路径
    :param dest_path:目标图片路径
    :param dest_width:目标图片宽
    :param dest_height:目标图片高
    :return: 
    """
    img=cv2.imread(src_path)
    height, width, channels = img.shape
    if width/height > dest_width/dest_height:
        # 源宽了，横向剪裁
        x = int(height*(width/height-dest_width/dest_height)/2)
        img_t = img[:,x:width-x]     #[纵向,横向]
    elif width/height < dest_width/dest_height:
        # 源高了了，纵向剪裁
        y = int(width*(height/width-dest_height/dest_width)/2)
        img_t = img[y:height-y,:]     #[纵向,横向]
    else:
        img_t = img
    img_dest = cv2.resize(img_t, (dest_width, dest_height),interpolation=cv2.INTER_CUBIC)
    cv2.imwrite(dest_path,img_dest)

clip_resize('src.jpg','test.jpg',int(1280),int(720))