Using height_field and width_field attribute in ImageField of Django

Question

I have a model

class Anh_chi_tiet(models.Model):
    du_an       = models.ForeignKey(Du_an)
    title       = models.CharField(max_length=120)
    url         = models.ImageField(upload_to='images', height_field='50', width_field='100')
    url_detail  = models.ImageField(upload_to='images', height_field='200', width_field='400')

I always receive this error:

'Anh_chi_tiet' object has no attribute '100'

It seems Django require both the fields in the same table Anh_chi_tiet to save height_field and width_field.

How can I directly set these values without append new fields in my table?

Answer 1

I think you are misunderstanding what the height_field and width_field attributes are for.

The height_field isn't used to change the height. It's used to record what the height already is.

This way you can do something like

<img src="..." height={{my_instance.my_height_field}} /> 

without having to read the file.

If you are trying to resize all images uploaded via an ImageField, check here: Image resizing with django?

Answer 2

height_field represents a property of your model which is used to store the height.

class Anh_chi_tiet(models.Model):

  url_height=models.PositiveIntegerField()
  url_width=models.PositiveIntegerField()
  url = models.ImageField(upload_to='images', height_field='url_height', width_field='url_width')

Notice height_field='url_height'