Python实现图像尺寸和格式转换处理的示例详解

# batch_handle_image.py

import argparse
import glob
import os
from PIL import Image


def main(args):
    limit_shortest = int(args.limitshortest)
    shortest_edge = int(args.shortestedge)
    longest_edge = int(args.longestedge)
    limit_width_or_height = int(args.limitwidthorheight)
    limit_width = int(args.limitwidth)
    limit_height = int(args.limitheight)
    to_WEBp = int(args.towebp)

    path_list = sorted(glob.glob(os.path.join(args.input, '*')))
    for path in path_list:
        print(path)
        basename = os.path.splitext(os.path.basename(path))[0]

        img = Image.open(path)
        width, height = img.size

        # 限制最长边或最短边
        if limit_shortest == 1:
            # save the smallest image which the shortest edge is shortest_edge
            if width < height:
                ratio = height / width
                width = shortest_edge
                height = int(width * ratio)
            else:
                ratio = width / height
                height = shortest_edge
                width = int(height * ratio)
        elif limit_shortest == 0:
            # save the smallest image which the longest edge is longest_edge
            if width < height:
                ratio = width / height
                height = longest_edge
                width = int(height * ratio)
            else:
                ratio = height / width
                width = longest_edge
                height = int(width * ratio)

        # 限制宽或高
        if limit_width_or_height == 0:
            # 限宽
            ratio = height / width
            width = limit_width
            height = int(width * ratio)
        elif limit_width_or_height == 1:
            # 限高
            ratio = width / height
            height = limit_height
            width = int(height * ratio)

        idx = 0

        rlt = img.resize((int(width), int(height)), resample=Image.ANTIALIAS)
        rlt = rlt.convert('RGB')
        rlt.save(os.path.join(args.output, f'{basename}T{idx+1}.png'), 'PNG')
        if to_webp == 1:
            os.makedirs(os.path.join(args.output, 'to_webp'), exist_ok=True)
            # 转换为 webp 格式图片
            rlt.save(os.path.join(args.output, 'to_webp', f'{basename}T{idx+1}.webp'), 'WEBP')


if __name__ == '__main__':
    """batch modify image size, and convert to webp
    """
    parser = argparse.ArgumentParser()
    parser.add_argument('--input', type=str, default='datasets/MY/YT', help='Input folder')
    parser.add_argument('--output', type=str, default='datasets/MY/YT_smallsize', help='Output folder')
    # 是否限制最短边开关：0-限制最长边；1-限制最短边；2-不限制
    parser.add_argument('--limitshortest', type=str, default='2', help='0-limit longest; 1-limit shortest; 2-not limit')
    # 设置最短边数值
    parser.add_argument('--shortestedge', type=str, default='500', help='shortest edge size')
    # 设置最长边数值
    parser.add_argument('--longestedge', type=str, default='2000', help='longest edge size')
    # 是否转换 webp 格式图像开关：0-不转换；1-转换
    parser.add_argument('--towebp', type=str, default='0', help='is convert to webp, 0-false, 1-true')
    # 是否限制宽度或高度数值开关
    parser.add_argument(
        '--limitwidthorheight',
        type=str,
        default='2',
        help='is limit width or height; 0-limit width; 1-limit height; 2-not limit')
    # 限制宽度数值，高度按比例计算
    parser.add_argument('--limitwidth', type=str, default='1080', help='limit width')
    # 限制高度数值，宽度按比例计算
    parser.add_argument('--limitheight', type=str, default='1080', help='limit height')
    args = parser.parse_args()

    os.makedirs(args.output, exist_ok=True)
    main(args)

# 限最长边 2000px，并将格式转换为 webp 格式
python batch_handle_image.py --input /input_image --output /output_image --limitshortest 0 --longestedge 2000 --towebp 1