django-image-cropping 1.0.4

=====================
django-image-cropping
=====================

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django-image-cropping is an app for cropping uploaded images via Django's admin backend using `Jcrop
<https://github.com/tapmodo/Jcrop>`_.

Screenshot:

.. image:: http://www.jonasundderwolf.de/media/images/django_image_cropping_example.png

django-image-cropping is perfect when you need images with a specific size for your templates but want your
users or editors to upload images of any dimension. It presents a selection with a fixed aspect ratio so your users
can't break the layout with oddly-sized images.

The original images are kept intact and only get cropped when they are displayed.
Large images are presented in a small format, so even very big images can easily be cropped.

The necessary fields, widgets and a template tag for displaying the
cropped image in your templates are provided.

Also works with `FeinCMS <https://github.com/feincms/feincms>`_ content types!

Installation
============

#. Install django-image-cropping using ``pip``::

pip install django-image-cropping

By default ``django-image-cropping`` ships with an ``easy-thumbnails``-backend which requires ``easy-thumbnails`` to also be installed
and added to the ``INSTALLED_APPS``.

The `easy-thumbnails` backend requires that you adjust the thumbnail processors in your ``settings``::

from easy_thumbnails.conf import Settings as thumbnail_settings
THUMBNAIL_PROCESSORS = (
'image_cropping.thumbnail_processors.crop_corners',
) + thumbnail_settings.THUMBNAIL_PROCESSORS


Configuration
=============

Add an ``ImageRatioField`` to the model that contains the ``ImageField`` for the images you want to crop.

The ``ImageRatioField`` simply stores the boundaries of the cropped image.
It expects the name of the associated ``ImageField`` and the desired size of the cropped image as arguments.

The size is passed in as a string and defines the aspect ratio of the selection *as well* as the minimum
size for the final image::

from django.db import models
from image_cropping import ImageRatioField

class MyModel(models.Model):
image = models.ImageField(blank=True, upload_to='uploaded_images')
# size is "width x height"
cropping = ImageRatioField('image', '430x360')

You can configure a `size warning`_ if users try to crop a selection smaller than the defined minimum.

Admin Integration
=================

Add the ``ImageCroppingMixin`` to your ``ModelAdmin``::

from django.contrib import admin
from image_cropping import ImageCroppingMixin

class MyModelAdmin(ImageCroppingMixin, admin.ModelAdmin):
pass

admin.site.register(MyModel, MyModelAdmin)

If your setup is correct you should now see the enhanced image widget that provides a selection
area.


Backends
========

django-image-cropping delegates the cropped image generation to a backend.

A backend based on `easy-thumbnails` is provided, but it's possible to use a custom backend.
The ``IMAGE_CROPPING_BACKEND`` setting expects a dotted path to a class that implements the required methods.
You can omit this setting if you want to use the default backend.

In case you use a custom backend you can provide an optional dict that will be used to populate the backend's
constructor params.

Default settings::

IMAGE_CROPPING_BACKEND = 'image_cropping.backends.easy_thumbs.EasyThumbnailsBackend'
IMAGE_CROPPING_BACKEND_PARAMS = {}


Frontend
========

django-image-cropping provides a templatetag for displaying a cropped thumbnail.
Any other processor parameter (like ``bw=True`` or ``upscale=True``) will be forwarded to the backend::

{% cropped_thumbnail yourmodelinstance "ratiofieldname" [scale=INT|width=INT|height=INT|max_size="INTxINT"] %}

Example usage::

{% load cropping %}
<img src="{% cropped_thumbnail yourmodel "cropping" scale=0.5 %}">

Or generate the URL from Python code in your view::

from image_cropping.utils import get_backend
thumbnail_url = get_backend().get_thumbnail_url(
yourmodel.image,
{
'size': (430, 360),
'box': yourmodel.cropping,
'crop': True,
'detail': True,
}
)


easy_thumbnails
---------------

You can also use the standard ``easy-thumbnails`` templatetag with the ``box`` parameter::

{% load thumbnail %}
{% thumbnail yourmodel.image 430x360 box=yourmodel.cropping crop detail %}

Or generate the URL from Python code in your view::

from easy_thumbnails.files import get_thumbnailer
thumbnail_url = get_thumbnailer(yourmodel.image).get_thumbnail({
'size': (430, 360),
'box': yourmodel.cropping,
'crop': True,
'detail': True,
}).url


ModelForm
=========

If you want to use the cropping widget outside the admin, you'll need to define the ``ImageField`` as
an ``ImageCropField``::

from django.db import models
from image_cropping import ImageCropField, ImageRatioField

class MyModel(models.Model):
image = ImageCropField(blank=True, upload_to='uploaded_images')
# size is "width x height"
cropping = ImageRatioField('image', '430x360')


Alternatively, override the widget in your ModelForm (you just need to do one of these two, not both!)::

from django import forms
from image_cropping import ImageCropWidget

class MyModelForm(forms.ModelForm):
class Meta:
widgets = {
'image': ImageCropWidget,
}


Remember to include the form media in the ``<head>`` of your HTML::

<html>
<head>
{{ form.media }}
</head>
<body>
{{ form }}
</body>
</html>

The cropping itself happens in the ``ImageRatioField``, the ``ImageCropField`` will still behave like a regular ``ImageField``.

If you're selectively including or excluding fields from the ModelForm, remember to include the ``ImageRatioField``.


Multiple formats
================

If you need the same image in multiple formats, simply specify another ``ImageRatioField``.
This will allow the image to be cropped twice::

from image_cropping import ImageRatioField, ImageCropField

image = ImageCropField(blank=True, upload_to='uploaded_images')
# size is "width x height"
list_page_cropping = ImageRatioField('image', '200x100')
detail_page_cropping = ImageRatioField('image', '430x360')

In your templates, use the corresponding ratio field::

{% load cropping %}
{% cropped_thumbnail yourmodel "list_page_cropping" %}


Foreign Keys
============

If you need to crop an image contained within another model, referenced by a ForeignKey, the ``ImageRatioField`` is
composed of the ``ForeignKey`` name, a double underscore, and the ``ImageField`` name::

from django.db import models
from image_cropping.fields import ImageRatioField

class Image(models.Model):
image_field = models.ImageField(upload_to='image/')

class NewsItem(models.Model):
title = models.CharField(max_length=255)
image = models.ForeignKey(Image)
cropping = ImageRatioField('image__image_field', '120x100')

Cropping foreign keys only works in the admin for now, as it reuses the ``raw_id`` widget.


.. _free cropping:

Free cropping
=============

If you do not need a *fixed* ratio, you can disable this constraint by setting ``free_crop`` to ``True``.
In this case the size parameter is the desired minimum and is also used for the size-warning::

from image_cropping import ImageRatioField, ImageCropField

image = ImageCropField(blank=True, upload_to='uploaded_images')

# size is "width x height" so a minimum size of 200px x 100px would look like this:
min_free_cropping = ImageRatioField('image', '200x100', free_crop=True)

Use the ``max_size`` parameter of the templatetag if you want to limit the display size of a thumbnail::

<img src="{% cropped_thumbnail image "cropping_free" max_size="200x200" %}" />


Disabling cropping
==================

If you want cropping to be optional, use ``allow_fullsize=True`` as an additional keyword argument for your ``ImageRatioField``.

Editors can now switch off cropping by unchecking a checkbox next to the image cropping widget::

image_with_optional_cropping = ImageRatioField('image', '200x100', allow_fullsize=True)


Settings
========

Thumbnail size
--------------

You can define the maximum size of the admin preview thumbnail in your ``settings``::

# size is "width x height"
IMAGE_CROPPING_THUMB_SIZE = (300, 300)

.. _size warning:

Size warning
------------

You can warn users about crop selections that are smaller than the size defined in the ``ImageRatioField``.
When users try to do a smaller selection, a red border appears around the image.

To use this functionality for a single image add the ``size_warning`` parameter to the ``ImageRatioField``::

cropping = ImageRatioField('image', '430x360', size_warning=True)

You can enable this functionality project-wide by adding the following line to your ``settings``::

IMAGE_CROPPING_SIZE_WARNING = True


Custom jQuery
-------------

By default the image cropping widget embeds a recent version of jQuery.

You can point to another version using the ``IMAGE_CROPPING_JQUERY_URL`` setting, though compatibility
issues may arise if your jQuery version differs from the one that is tested against.

You can also set ``IMAGE_CROPPING_JQUERY_URL`` to ``None`` to disable inclusion of jQuery by the widget.
You are now responsible for including ``jQuery`` yourself, both in the frontend and in the admin interface.

Custom backend
--------------

You can define a custom backend::

IMAGE_CROPPING_BACKEND = 'image_cropping.backends.easy_thumbs.EasyThumbnailsBackend'

You can provide an optional dict that will be used to populate the backend's
constructor::

IMAGE_CROPPING_BACKEND_PARAMS = {'version_suffix': 'thumb'}

.. seealso::

See the built-in backends on Backends_.


Troubleshooting
===============

The cropping widget is not displayed when using a ``ForeignKey``.
Make sure you do **not** add the corresponding image field to ``raw_id_fields``.


Changelog
=========

1.1 (unreleased)
----------------

- Move and encapsulate the logic for creating cropped thumbnails to a swappable backend. (`@fgmacedo <https://github.com/fgmacedo>`_ in #92)

1.0
---

"If your software is being used in production, it should probably already be 1.0.0." (http://semver.org)

0.9
---

This release addresses mainly the test coverage and internal stuff.

Noteable (breaking) changes and things to be considered when upgrading from an older version:

- `django-appconf <https://github.com/jezdez/django-appconf>`_ is now used for handling defaults and settings.

* **Breaking Change**: JQUERY_URL changed to IMAGE_CROPPING_JQUERY_URL as part of this transition.

- The ``cropped_thumbnail`` tag is now based on Django's ``simple tag``.

* **Breaking Change**: Arguments for the the tag now need to be put in quotes.
* If you are still using Django 1.4 remember that `you can't easily use <http://stackoverflow.com/q/11804315/630877>`_ ``True`` or ``False`` as template tag arguments.

- Any processor parameter (like bw=True or upscale=True) can be used in the ``cropped_thumbnail`` tag.

- Moved inline css to a dedicated ``image_cropping.css`` style sheet

0.8
---

- **Minimum** requirements changed to **Django 1.4** and **easy-thumbnails 1.4**
- Added Python 3 compatibility. Python 2.6 is now the minimum required Python version.
- Added a `free cropping`_ option, so cropping is no longer restricted to fixed ratios.
- Removed the deprecated ``CropForeignKey`` field.

0.7
---

- Made the widget for the ``ImageCropField`` overwriteable to allow custom widgets. (Remember to use the ``ImageCroppingMixin`` in the admin as the image cropping widgets are no longer implicitly set.)
- Updated ``Jcrop`` and ``jQuery`` dependencies.
- Moved docs to *Read the Docs*: https://django-image-cropping.readthedocs.org