Features

• uses Pillow to resize images

• uses Django’s default_storage to let you play with whatever storage backend you’ll need

• uploaded image files named using uuid

• rendition cached on disk

• resize keeping original aspect ratio

• crop if needed

• simple widget for admin site

Quick start

Install the app.

pip install django-image-renderer

Add “renderer” to your INSTALLED_APPS setting like this:

settings.py

INSTALLED_APPS = (
    # your apps
    'renderer',
)

Include the renderer URL configuration in your project urls.py like this:

urls.py

url(r'^renderer/', include('renderer.urls', namespace='renderer')),

Run python manage.py migrate to create the renderer models.

Start the development server and visit http://localhost:8000/admin/ to create a MasterImage (you’ll need the Admin app enabled).

Requirements

• Python (2.7, 3.4, 3.5)

• Django (1.7, 1.8, 1.9)

Usage

There is only one model in the app: MasterImage. With a MasterImage you can ask for renditions.

m = MasterImage.objects.first()

# get the master file's URL
m.get_master_url()
# or
m.get_rendition_url(0, 0)

# cache and return URL of a renditions that as 200 pixels width
# and height computed according to master's aspect ratio
url = m.get_rendition_url(200, 0)

# cache and return URL of a renditions that as 50 pixels height
# and width computed according to master's aspect ratio
url = m.get_rendition_url(0, 50)

If you ask for a size that do not fit master’s aspect ration you’ll receive a center cropped image.

You can also ask for a rendition in templates.

models.py

def index(request):
    m = MasterImage.objects.first()
    return render(request, 'demo/index.html', {
        'master': m,
    })

index.html

{% load renderer %}
...
{% rendition master 42 42 %}
...
{% rendition_url 42 42 %}
...

This will render as:

<img src="/media/img/0fb34de8-9d83-456a-828b-72ab21f8ebab_42x42.png" width="42" height="42" alt="">
...
/media/img/0fb34de8-9d83-456a-828b-72ab21f8ebab_42x42.png
...

When using MasterImage in your model you may need a widget who provides a preview for you image. For convenience a mixin is provided.

models.py

from django.db import models

class DemoModel(models.Model):
    master = models.ForeignKey('renderer.MasterImage')

admin.py

from demo.models import DemoModel
from django.contrib import admin
from renderer.widgets import MasterImageAdminMixin

@admin.register(DemoModel)
class DemoModelAdmin(MasterImageAdminMixin, admin.ModelAdmin):
    fields = ('master', )

Sample project

A sample project is available in the sample folder. Test it as an usual Django project:

virtualenv --no-site-packages venv
source venv/bin/activate
pip install -r requirements.txt
python sample/manage.py migrate
python sample/manage.py createsuperuser
python sample/manage.py runserver

It’ also deployed at http://django-image-renderer.herokuapp.com/.