Django reverse page object numeration

Question

I use {{ forloop.counter0|add:page_obj.start_index }} And get (pagination 3):

Page1: 1  Page2: 4
       2         5
       3

If I use {{ forloop.revcounter0|add:page_obj.start_index }} I get:

Page1: 3  Page2: 5
       2         4
       1

How can I get:

Page1: 5  Page2: 2
       4         1
       3

I was thinking something like {{ paginator.count|add:SOMETHING }}

Answer 1

The best solution would be to write a custom template tag to do this. In some suitable app of yours make a directory templatetags.py and also add a file __init__.py in it. Inside directory make a new file in which we will write template tags lets say pagination_extras.py. After this your directory structure would look something like:

<appname>/
    __init__.py
    models.py
    templatetags/
        __init__.py
        pagination_extras.py
    views.py

Now in pagination_extras.py make a custom template tag to do this calculation for you:

from django import template

register = template.Library()

@register.simple_tag
def pagination_reverse_numbering(paginator, page_obj, loop_count):
    return paginator.count - page_obj.start_index() - loop_count + 1

Now in your template you will first load this tag and then use it to perform your numbering:

{% load pagination_extras %}
...
{% for item in page_obj %}
    {% pagination_reverse_numbering paginator page_obj forloop.counter0 %}
{% endfor %}