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from django.core.exceptions import FieldDoesNotExist, ImproperlyConfigured
from django.db.models import CharField, signals
from django.db.models.fields.files import ImageField
from colorfield.utils import get_image_file_background_color
from colorfield.validators import color_hex_validator, color_hexa_validator
from colorfield.widgets import ColorWidget
VALIDATORS_PER_FORMAT = {"hex": color_hex_validator, "hexa": color_hexa_validator}
DEFAULT_PER_FORMAT = {"hex": "#FFFFFF", "hexa": "#FFFFFFFF"}
class ColorField(CharField):
default_validators = []
def __init__(self, *args, **kwargs):
# works like Django choices, but does not restrict input to the given choices
self.samples = kwargs.pop("samples", None)
self.format = kwargs.pop("format", "hex").lower()
if self.format not in ["hex", "hexa"]:
raise ValueError("Unsupported color format: {}".format(self.format))
self.default_validators = [VALIDATORS_PER_FORMAT[self.format]]
self.image_field = kwargs.pop("image_field", None)
if self.image_field:
kwargs.setdefault("blank", True)
kwargs.setdefault("max_length", 18)
if kwargs.get("null"):
kwargs.setdefault("blank", True)
kwargs.setdefault("default", None)
elif kwargs.get("blank"):
kwargs.setdefault("default", "")
else:
kwargs.setdefault("default", DEFAULT_PER_FORMAT[self.format])
super(ColorField, self).__init__(*args, **kwargs)
if self.choices and self.samples:
raise ImproperlyConfigured(
"Invalid options: 'choices' and 'samples' are mutually exclusive, "
"you can set only one of the two for a ColorField instance."
)
def formfield(self, **kwargs):
palette = []
if self.choices:
choices = self.get_choices(include_blank=False)
palette = [choice[0] for choice in choices]
elif self.samples:
palette = [choice[0] for choice in self.samples]
kwargs["widget"] = ColorWidget(
attrs={
"default": self.get_default(),
"format": self.format,
"palette": palette,
# # this will be used to hide the widget color spectrum if choices is defined:
# 'palette_choices_only': bool(self.choices),
}
)
return super(ColorField, self).formfield(**kwargs)
def contribute_to_class(self, cls, name, **kwargs):
super(ColorField, self).contribute_to_class(cls, name, **kwargs)
if cls._meta.abstract:
return
if self.image_field:
signals.post_save.connect(self._update_from_image_field, sender=cls)
def deconstruct(self):
name, path, args, kwargs = super(ColorField, self).deconstruct()
kwargs["samples"] = self.samples
kwargs["image_field"] = self.image_field
return name, path, args, kwargs
def _get_image_field_color(self, instance):
color = ""
image_file = getattr(instance, self.image_field)
if image_file:
alpha = self.format == "hexa"
with image_file.open() as _:
color = get_image_file_background_color(image_file, alpha)
return color
def _update_from_image_field(self, instance, created, *args, **kwargs):
if not instance or not instance.pk or not self.image_field:
return
# check if the field is a valid ImageField
try:
field_cls = instance._meta.get_field(self.image_field)
if not isinstance(field_cls, ImageField):
raise ImproperlyConfigured(
'Invalid "image_field" field type, '
'expected an instance of "models.ImageField".'
)
except FieldDoesNotExist:
raise ImproperlyConfigured(
'Invalid "image_field" field name, '
'"{}" field not found.'.format(self.image_field)
)
# update value from picking color from image field
color = self._get_image_field_color(instance)
color_field_name = self.attname
color_field_value = getattr(instance, color_field_name, None)
if color_field_value != color and color:
color_field_value = color or self.default
# update in-memory value
setattr(instance, color_field_name, color_field_value)
# update stored value
manager = instance.__class__.objects
manager.filter(pk=instance.pk).update(
**{color_field_name: color_field_value}
)
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