django-ultimatethumb 0.6.0

What is django-ultimatethumb

django-ultimatethumb is another Django library for generating thumbnails but has some advantages:

• Thumbnails are not generated when the templatetag is called. Instead, images are generated on demand when they are requested by the browser. This can lead to a major speedup of your page response times.
• Thumbnails can be generated from static files too (for example to downscale retina-optimized images and therefore reducing traffic).
• Generate multiple thumbnail sizes at once for use in picture html tags with multiple sources (e.g. with media queries).

Hint

The documentation is still work in progress but the library is already in use for a while now. We working hard on providing a better documentation!

Quick start

To install django-ultimatethumb just use your preferred Python package installer:

$ pip install django-ultimatethumb

Add some stuff to your Django settings

INSTALLED_APPS = (
    # some other apps
    'ultimatethumb',
)

# This is the path where the generated thumbnail files are cached.
ULTIMATETHUMB_ROOT = '/filesystem/path/to/thumbnails/'
# This is the base url for your thumbnails
ULTIMATETHUMB_URL = '/thumbnails/'

Next, add the django-ultimatethumb urls to your urls.py

urlpatterns += patterns(
    '',
    url(
        r'^{0}/'.format(settings.ULTIMATETHUMB_URL.strip('/')),
        include('ultimatethumb.urls')
    ),

Hint

You can use the ULTIMATETHUMB_URL setting in your urls.py to make sure that the urls are in sync.

To use django-ultimatethumb in your templates, just load the templatetags and call the ultimatethumb tag with proper parameters:

{% load ultimatethumb_tags %}
{% ultimatethumb 'mythumb' mymodel.imagefield.name sizes='200x0,400x0' %}
<picture>
{% for source in mythumb %}
    <source
        srcset="{{ source.url_2x }} 2x, {{ source.url }} 1x"
        {% if not forloop.last %}media="(max-width: {{ source.viewport.width }}px)"{% endif %}
    />
    {% if forloop.last %}<img src="{{ source.url }}" />{% endif %}
{% endfor %}
</picture>

This gives you a full-featured picture tag including multiple sources with media queries for different browser sizes and also provides retina images.

You can also use django-ultimatethumb in a much simpler way:

{% load ultimatethumb_tags %}
{% ultimatethumb 'mythumb' mymodel.imagefield.name sizes='400x0' %}
<img src="{{ mythumb.0.url }}" />

To resize static images, just prefix the path with static:, for example:

{% load ultimatethumb_tags %}
{% ultimatethumb 'mythumb' 'static:img/logo.jpg' sizes='400x0' %}
<img src="{{ mythumb.0.url }}" />

There are many other options/parameters to pass to the templatetag. Please refer to the codebase until the documentation is more complete.

You can also pass the viewport size in addition to the requested thumbnail size:

{% load ultimatethumb_tags %}
{% ultimatethumb 'mythumb' 'static:img/logo.jpg' sizes='400x0:600x0' %}
<img src="{{ mythumb.0.url }}" />

This will set the thumbnail.viewport.width to 600.

If you want so save some characters, you might short cut the sizes by leaving out the “x0” for the auto’ed dimesion.

{% load ultimatethumb_tags %}
{% ultimatethumb 'mythumb' 'static:img/logo.jpg' sizes='400:600' %}
<img src="{{ mythumb.0.url }}" />

The sizes are now the same as if you would use sizes=‘400x0,600x0’.

Options

You can pass some options to the thumbnail tag:

• upscale: Configures if the input should be upscaled if requested sizes are larger than source.
• retina: Option to enable retina support (by providing both url and url_2x)
• crop: Deside if images should be cropped if requested sizes doesn’t fit source aspect ratio.
• quality: Configures quality for image compression
• pngquant: Configures the pngquant compression factor

Hint

The crop option can be set to True for default gravity when cropping (which is Center). You can also pass valid GraphicsMagick gravities (North, NorthEeast, East, SouthEast, …) or their abbreviation (N, NE, E, SE, …)