Python pillow模块出现cannot write mode RGBA as JPEG问题的解决方法

谁借莪１个温暖的怀抱￠ 2022-12-31 05:24 242阅读 0赞

# 背景 #

最近在解决一个问题:如何自动截取Excel里面的范围为图片并发送.最后使用`pywin32`模块解决了,但是在发送的时候,个别部署电脑会出现一些问题,就是下面这种报错

cannot write mode RGBA as JPEG

后来发现有些电脑在使用VBA的`CopyPicture`方法会默认为PNG格式,有些默认是JPG格式,奇奇怪怪的

# 问题 #

出现问题的是下面这一段,为了更好理解,我将上下文放了出来

img = ImageGrab.grabclipboard()
    imgpath = os.path.join(os.path.dirname(__file__),'{imgname}.{fmt}'.format(imgname=time.strftime('%Y%m%d%H%M%S'),fmt=fmt))
    img.save(imgpath) # 这一句有报错

报错完整信息如下

Traceback (most recent call last):
      File "C:\Users\Administrator\AppData\Local\Programs\Python\Python39\lib\site-packages\PIL\JpegImagePlugin.py", line 611, in _save
        rawmode = RAWMODE[im.mode]
    KeyError: 'RGBA'
    
    The above exception was the direct cause of the following exception:
    
    Traceback (most recent call last):
      File "D:\onedrive\doc\for_share\Python_eco\python\work_wechat_amiba.py", line 22, in <module>
        amiba()
      File "D:\onedrive\doc\for_share\Python_eco\python\work_wechat_amiba.py", line 14, in amiba
        img = excel.savePic(['post'],'jpg')
      File "D:\onedrive\doc\for_share\Python_eco\python\Udfs\cls_excel.py", line 80, in savePic
        img.save(self._picPath)
      File "C:\Users\Administrator\AppData\Local\Programs\Python\Python39\lib\site-packages\PIL\Image.py", line 2151, in save
        save_handler(self, fp, filename)
      File "C:\Users\Administrator\AppData\Local\Programs\Python\Python39\lib\site-packages\PIL\JpegImagePlugin.py", line 613, in _save
        raise OSError(f"cannot write mode {im.mode} as JPEG") from e
    OSError: cannot write mode RGBA as JPEG

# 方案 #

解决方案也是非常简单,加一句转换就可以了

# 结论 #

1.  如果保存格式为`jpg`,最好加上这句转换
2.  如果保存格式为`png`,可以不用这句

如果有一个格式变量,那最终加进去的如下

if fmt == 'jpg':
    	img.convert('RGB')