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auto compress product icons
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e2b42145e1
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125
core/fields.py
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125
core/fields.py
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from pathlib import Path
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from django.core.exceptions import FieldError
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from django.db import models
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from django.db.models.fields.files import ImageFieldFile
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from PIL import Image
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from core.utils import resize_image_explicit
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class ResizedImageFieldFile(ImageFieldFile):
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def get_resized_dimensions(self, image: Image.Image) -> tuple[int, int]:
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"""Get the dimensions of the resized image.
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If the width and height are given, they are used.
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If only one is given, the other is calculated to keep the same ratio.
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Returns:
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Tuple of width and height
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"""
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width = self.field.width
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height = self.field.height
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if width is not None and height is not None:
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return self.field.width, self.field.height
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if width is None:
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width = int(image.width * height / image.height)
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elif height is None:
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height = int(image.height * width / image.width)
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return width, height
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def get_name(self) -> str:
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"""Get the name of the resized image.
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If the field has a force_format attribute,
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the extension of the file will be changed to match it.
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Otherwise, the name is left unchanged.
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Raises:
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ValueError: If the image format is unknown
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"""
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if not self.field.force_format:
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return self.name
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formats = {val: key for key, val in Image.registered_extensions().items()}
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new_format = self.field.force_format
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if new_format in formats:
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extension = formats[new_format]
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else:
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raise ValueError(f"Unknown format {new_format}")
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return str(Path(self.file.name).with_suffix(f".{extension}"))
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def save(self, name, content, save=True): # noqa FBT002
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content.file.seek(0)
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img = Image.open(content.file)
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width, height = self.get_resized_dimensions(img)
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img_format = self.field.force_format or img.format
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new_content = resize_image_explicit(img, (width, height), img_format)
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name = self.get_name()
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return super().save(name, new_content, save)
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class ResizedImageField(models.ImageField):
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"""A field that automatically resizes images to a given size.
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This field is useful for profile pictures or product icons, for example.
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The final size of the image is determined by the width and height parameters :
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- If both are given, the image will be resized
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to fit in a rectangle of width x height
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- If only one is given, the other will be calculated to keep the same ratio
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If the force_format parameter is given, the image will be converted to this format.
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Examples:
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To resize an image with a height of 100px, without changing the ratio,
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and a format of WEBP :
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```python
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class Product(models.Model):
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icon = ResizedImageField(height=100, force_format="WEBP")
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```
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To explicitly resize an image to 100x100px (but possibly change the ratio) :
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```python
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class Product(models.Model):
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icon = ResizedImageField(width=100, height=100)
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```
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Raises:
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FieldError: If neither width nor height is given
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Args:
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width: If given, the width of the resized image
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height: If given, the height of the resized image
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force_format: If given, the image will be converted to this format
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"""
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attr_class = ResizedImageFieldFile
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def __init__(
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self,
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width: int | None = None,
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height: int | None = None,
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force_format: str | None = None,
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**kwargs,
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):
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if width is None and height is None:
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raise FieldError(
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f"{self.__class__.__name__} requires "
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"width, height or both, but got neither"
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)
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self.width = width
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self.height = height
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self.force_format = force_format
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super().__init__(**kwargs)
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def deconstruct(self):
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name, path, args, kwargs = super().deconstruct()
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if self.width is not None:
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kwargs["width"] = self.width
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if self.height is not None:
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kwargs["height"] = self.height
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kwargs["force_format"] = self.force_format
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return name, path, args, kwargs
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@ -25,7 +25,7 @@ from django.core.files.base import ContentFile
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from django.http import HttpRequest
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from django.utils import timezone
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from PIL import ExifTags
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from PIL.Image import Resampling
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from PIL.Image import Image, Resampling
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def get_start_of_semester(today: Optional[date] = None) -> date:
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@ -82,18 +82,20 @@ def get_semester_code(d: Optional[date] = None) -> str:
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return "P" + str(start.year)[-2:]
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def scale_dimension(width, height, long_edge):
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ratio = long_edge / max(width, height)
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return int(width * ratio), int(height * ratio)
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def resize_image(im, edge, img_format):
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def resize_image(im: Image, edge: int, img_format: str):
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"""Resize an image to fit the given edge length and format."""
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(w, h) = im.size
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(width, height) = scale_dimension(w, h, long_edge=edge)
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ratio = edge / max(w, h)
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(width, height) = int(w * ratio), int(h * ratio)
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return resize_image_explicit(im, (width, height), img_format)
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def resize_image_explicit(im: Image, size: tuple[int, int], img_format: str):
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"""Resize an image to the given size and format."""
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img_format = img_format.upper()
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content = BytesIO()
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# use the lanczos filter for antialiasing and discard the alpha channel
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im = im.resize((width, height), Resampling.LANCZOS)
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im = im.resize((size[0], size[1]), Resampling.LANCZOS)
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if img_format == "JPEG":
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# converting an image with an alpha channel to jpeg would cause a crash
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im = im.convert("RGB")
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37
counter/migrations/0022_alter_product_icon.py
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37
counter/migrations/0022_alter_product_icon.py
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# Generated by Django 4.2.16 on 2024-09-14 18:02
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from django.db import migrations
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import core.fields
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class Migration(migrations.Migration):
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dependencies = [
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("counter", "0021_rename_check_cashregistersummaryitem_is_checked"),
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]
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operations = [
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migrations.AlterField(
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model_name="product",
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name="icon",
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field=core.fields.ResizedImageField(
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blank=True,
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height=70,
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force_format="WEBP",
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null=True,
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upload_to="products",
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verbose_name="icon",
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),
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),
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migrations.AlterField(
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model_name="producttype",
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name="icon",
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field=core.fields.ResizedImageField(
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blank=True,
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force_format="WEBP",
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height=70,
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null=True,
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upload_to="products",
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),
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),
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]
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@ -37,6 +37,7 @@ from django_countries.fields import CountryField
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from accounting.models import CurrencyField
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from club.models import Club
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from core.fields import ResizedImageField
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from core.models import Group, Notification, User
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from core.utils import get_start_of_semester
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from sith.settings import SITH_COUNTER_OFFICES, SITH_MAIN_CLUB
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@ -208,7 +209,9 @@ class ProductType(models.Model):
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name = models.CharField(_("name"), max_length=30)
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description = models.TextField(_("description"), null=True, blank=True)
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comment = models.TextField(_("comment"), null=True, blank=True)
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icon = models.ImageField(upload_to="products", null=True, blank=True)
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icon = ResizedImageField(
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height=70, force_format="WEBP", upload_to="products", null=True, blank=True
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)
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# priority holds no real backend logic but helps to handle the order in which
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# the items are to be shown to the user
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@ -250,8 +253,13 @@ class Product(models.Model):
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purchase_price = CurrencyField(_("purchase price"))
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selling_price = CurrencyField(_("selling price"))
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special_selling_price = CurrencyField(_("special selling price"))
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icon = models.ImageField(
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upload_to="products", null=True, blank=True, verbose_name=_("icon")
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icon = ResizedImageField(
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height=70,
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force_format="WEBP",
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upload_to="products",
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null=True,
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blank=True,
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verbose_name=_("icon"),
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)
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club = models.ForeignKey(
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Club, related_name="products", verbose_name=_("club"), on_delete=models.CASCADE
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6
docs/reference/core/model_fields.md
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6
docs/reference/core/model_fields.md
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::: core.fields
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handler: python
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options:
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members:
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- ResizedImageFieldFile
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- ResizedImageField
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- reference/com/views.md
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- core:
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- reference/core/models.md
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- Champs de modèle: reference/core/model_fields.md
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- reference/core/views.md
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- reference/core/schemas.md
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- reference/core/api_permissions.md
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