批量将PNG转为JPG

àì夳堔傛蜴生んèń 2023-01-18 02:20 162阅读 0赞

因为最近想把自己的“认知卡片”项目上云，受限于PNG文件尺寸和有限带宽的矛盾，于是需要将近千张PNG转为JPG，从而在基本维持分辨率和图像视觉质量的前提下，使得文件大小缩减为原图的大约13%。代码如下：

""" 先来说一下jpg图片和png图片的区别 jpg格式:是有损图片压缩类型,可用最少的磁盘空间得到较好的图像质量 png格式:不是压缩性,能保存透明等图 先安装opencv包：pip install opencv-contrib-python """
    from PIL import Image
    import cv2 as cv
    import os
    
    
    # PNG到JPG的转换函数
    def png2jpg(png_path):
        img = cv.imread(png_path, 0)
        w, h = img.shape[::-1]
        infile = png_path
        outfile = os.path.splitext(infile)[0] + ".jpg"
        img = Image.open(infile)
        img = img.resize((int(w), int(h)), Image.ANTIALIAS)
        try:
            if len(img.split()) == 4:
                # prevent IOError: cannot write mode RGBA as BMP
                r, g, b, a = img.split()
                img = Image.merge("RGB", (r, g, b))
                img.convert('RGB').save(outfile, quality=90)
                os.remove(png_path)
            else:
                img.convert('RGB').save(outfile, quality=90)
                os.remove(png_path)
            return outfile
        except Exception as e:
            print("PNG转换JPG 错误", e)
    
    
    # 递归遍历PNG文件
    def show_files(path, all_files):
        # 首先遍历当前目录所有文件及文件夹
        file_list = os.listdir(path)
        # 准备循环判断每个元素是否是文件夹还是文件，是文件的话，把名称传入list，是文件夹的话，递归
        for file in file_list:
            # 利用os.path.join()方法取得路径全名，并存入cur_path变量，否则每次只能遍历一层目录
            cur_path = os.path.join(path, file)
            # 判断是否是文件夹
            if os.path.isdir(cur_path):
                show_files(cur_path, all_files)
            else:
                # print(cur_path)
                filename, ext = os.path.splitext(file)
                if ext == ".png":
                    print("PNG:" + cur_path)
                    png2jpg(cur_path)
                all_files.append(file)
    
        return all_files
    
    
    if __name__ == '__main__':
        # 传入空的list接收文件名
        contents = show_files(r"C:\Users\CTH\Desktop\tmp", [])

参考：  
[https://www.cnblogs.com/jiyanjiao-702521/p/10442416.html][https_www.cnblogs.com_jiyanjiao-702521_p_10442416.html]  
[https://www.cnblogs.com/cnapple/p/11792577.html][https_www.cnblogs.com_cnapple_p_11792577.html]

[https_www.cnblogs.com_jiyanjiao-702521_p_10442416.html]: https://www.cnblogs.com/jiyanjiao-702521/p/10442416.html
[https_www.cnblogs.com_cnapple_p_11792577.html]: https://www.cnblogs.com/cnapple/p/11792577.html