python - 使用 PIL 在 Django 中调整上传文件的大小

Question

我正在使用 PIL 通过这种方法调整上传文件的大小:

def resize_uploaded_image(buf):
  imagefile = StringIO.StringIO(buf.read())
  imageImage = Image.open(imagefile)

  (width, height) = imageImage.size
  (width, height) = scale_dimensions(width, height, longest_side=240)

  resizedImage = imageImage.resize((width, height))
return resizedImage

然后我使用此方法在我的主视图方法中获取调整大小的图像:

image = request.FILES['avatar']
resizedImage = resize_uploaded_image(image)
content = django.core.files.File(resizedImage)
acc = Account.objects.get(account=request.user)
acc.avatar.save(image.name, content)

但是，这给了我“读取”错误。

跟踪:

Exception Type: AttributeError at /myapp/editAvatar Exception Value: read

知道如何解决这个问题吗？我已经做了好几个小时了!谢谢!

尼昆杰

Answer 1

以下是获取类文件对象的方法，在 PIL 中将其作为图像进行操作，然后将其转回类文件对象:

def resize_uploaded_image(buf):
    image = Image.open(buf)

    (width, height) = image.size
    (width, height) = scale_dimensions(width, height, longest_side=240)

    resizedImage = image.resize((width, height))

    # Turn back into file-like object
    resizedImageFile = StringIO.StringIO()
    resizedImage.save(resizedImageFile , 'PNG', optimize = True)
    resizedImageFile.seek(0)    # So that the next read starts at the beginning

    return resizedImageFile

请注意，PIL 图像已经有一个方便的 thumbnail() 方法。这是我在自己的项目中使用的缩略图代码的变体:

def resize_uploaded_image(buf):
    from cStringIO import StringIO
    import Image

    image = Image.open(buf)

    maxSize = (240, 240)
    resizedImage = image.thumbnail(maxSize, Image.ANTIALIAS)

    # Turn back into file-like object
    resizedImageFile = StringIO()
    resizedImage.save(resizedImageFile , 'PNG', optimize = True)
    resizedImageFile.seek(0)    # So that the next read starts at the beginning

    return resizedImageFile