python - 尝试将 .gif 文件转换为 .jpeg 时 Django 抛出 IO 错误

Question

我是 python 世界的新手。对于一个项目(使用 django)，我使用 PIL 库将 .gif 文件转换为 .jpg 文件。但是当运行模型的保存方法时，它会抛出“IOError at ... cannot write mode P as JPEG”

这是我的模型类。请给我一个解决方案。提前致谢。

class ImageArtwork(models.Model):
    filepath = 'art_images/'
    artwork = models.ForeignKey(Artwork, related_name='images')
    artwork_image = models.ImageField(_(u"Dieses Bild hinzufügen: "), upload_to=filepath)
    image_medium = models.CharField(max_length=255, blank=True)
    image_thumb = models.CharField(max_length=255, blank=True)
    uploaded_at = models.DateTimeField(auto_now_add=True)

    def get_thumb(self):
        return "/media/%s" % self.image_thumb

    def get_medium(self):
        return "/media/%s" % self.image_medium

    def get_original(self):
        return "/media/%s" % self.artwork_image

    def save(self):
        sizes = {'thumbnail': {'height': 50, 'width': 50}, 'medium': {'height': 300, 'width': 300}, }

        # Check if the number of images for the artwork has already reached maximum limit

        if ImageArtwork.objects.filter(artwork=self.artwork).count() < 6:
            super(ImageArtwork, self).save()
            photopath = str(self.artwork_image.path)        # this returns the full system path to the original file
            im = Image.open(photopath)      # open the image using PIL

            # pull a few variables out of that full path
            extension = photopath.rsplit('.', 1)[1]     # the file extension
            filename = photopath.rsplit('/', 1)[1].rsplit('.', 1)[0]  # the file name only (minus path or extension)
            fullpath = photopath.rsplit('/', 1)[0]      # the path only (minus the filename.extension)

            # use the file extension to determine if the image is valid before proceeding
            if extension.lower() not in ['jpg', 'jpeg', 'gif', 'png']:
                return
            im = ImageOps.fit(im, (sizes['medium']['width'], sizes['medium']['height']), Image.ANTIALIAS)       # create medium image
            medname = filename + "_" + str(sizes['medium']['width']) + "x" + str(sizes['medium']['height']) + ".jpg"
            im.save(fullpath + '/' + medname)
            self.image_medium = '/media/' + self.filepath + medname
            im = ImageOps.fit(im, (sizes['thumbnail']['width'], sizes['thumbnail']['height']), Image.ANTIALIAS)     # create thumbnail
            thumbname = filename + "_" + str(sizes['thumbnail']['width']) + "x" + str(
                sizes['thumbnail']['height']) + ".jpg"
            im.save(fullpath + '/' + thumbname)
            self.image_thumb = '/media/' + self.filepath + thumbname
            super(ImageArtwork, self).save()

        else:
            pass

Answer 1

cannot write mode P as JPEG

这不是 django 的问题，这是图像库的限制。

P 代表调色板。 PIL 在写入 JPEG 时尝试保留原始图像的颜色模式。由于 JPEG 仅支持“TrueColor”(即 RGB)图像，因此在转换(调色板)GIF 文件时会出现此错误。

保存为 JPEG 时始终将图像转换为 RGB:

im.convert('RGB').save(fullpath + '/' + medname)