(Django) 如何将值从字段传输到模型内的自定义 ImageKit 处理器？

Question

我用Django ImageKit来process/crop上传照片。我添加了自己的自定义处理器以向照片添加文本（如水印）：

# ./example/processors.py

from django.conf import settings
from PIL import Image, ImageDraw, ImageFont

_default_font = ImageFont.truetype(settings.TEXT_OVERLAY_FONT_REGULAR, 24)


def add_text_overlay(image, text, font=_default_font):
    rgba_image = image.convert('RGBA')
    text_overlay = Image.new('RGBA', rgba_image.size, (255, 255, 255, 0))

    image_draw = ImageDraw.Draw(text_overlay)
    text_size_x, text_size_y = image_draw.textsize(text, font=font)
    text_xy = ((rgba_image.size[0] / 2) - (text_size_x / 2), (rgba_image.size[1] / 2) - (text_size_y / 2))

    image_draw.text(text_xy, text, font=font, fill=(255, 255, 255, 255))
    image_with_text_overlay = Image.alpha_composite(rgba_image, text_overlay)

    return image_with_text_overlay


class TextOverlayProcessor(object):
    def __init__(self, text='Lorem ipsum dolor sit amet'):
        """
        :param text: The overlay text, string.

        """
        self.text = text

    def process(self, img):
        return add_text_overlay(image=img, text=self.text)

但是如何将值从字段传输到模型内的自定义 ImageKit 处理器？像这样：

# ./example/models.py

from imagekit.models import ImageSpecField
from imagekit.processors import ResizeToFill
from .processors import TextOverlayProcessor


class Example(models.Model):
    description = models.CharField('Description', ...)
    image = models.ImageField('Picture', default=None)

    image_800x800 = ImageSpecField(
        source='image',
        processors=[
            ResizeToFill(800, 800), 
            TextOverlayProcessor(text=self.description) # but `self` is wrong and raise error
        ], 
        format='JPEG',
        options={'quality': 100}
    )
    ...

我很乐意对用例进行解释性评论and/or。

Answer 1

简短的回答是

来自官方docs:

Often, when using an ImageSpecField, you may want the spec to vary based on properties of a model. (For example, you might want to store image dimensions on the model and then use them to generate your thumbnail.) Now that we know how to access the source image from our spec, it’s a simple matter to extract its model and use it to create our processors list. In fact, ImageKit includes a utility for getting this information.

(Django) 如何将值从字段传输到模型内的自定义 ImageKit 处理器？

(Django) How to transfer value from field to the custom ImageKit processor inside the model?

django

django-imagekit