Wagtail Exact Crop

Exact image cropping for Wagtail content editors.

Give content editors precise control over image crops in the Wagtail image admin. Instead of relying on focal points, editors move and scale the image inside fixed crop areas and see the result immediately.

Installation

pip install wagtail-exact-crop

Add wagtail_exact_crop to installed apps:

INSTALLED_APPS = [
    "wagtail_exact_crop",
    ...
]

Use the ExactCropImageMixin to add the exact_crops field to your custom image model:

from django.db import models
from wagtail.images.models import AbstractImage, AbstractRendition
from wagtail_exact_crop.models import ExactCropImageMixin


class CustomImage(ExactCropImageMixin, AbstractImage):
    admin_form_fields = (
        "title",
        "file",
        "description",
        "collection",
        "tags",
        "focal_point_x",
        "focal_point_y",
        "focal_point_width",
        "focal_point_height",
        "exact_crops",  # !
    )


class CustomRendition(AbstractRendition):
    image = models.ForeignKey(
        CustomImage,
        on_delete=models.CASCADE,
        related_name="renditions",
    )

    class Meta:
        unique_together = (("image", "filter_spec", "focal_point_key"),)

Define the custom image model in your settings:

WAGTAILIMAGES_IMAGE_MODEL = "images.CustomImage"

After adding the model, run makemigrations and migrate.

Define crop sizes:

WAGTAIL_EXACT_IMAGE_CROP_PRESETS = {
    "avatar": {"width": 300, "height": 300},
    "medium_shot": {"width": 400, "height": 800},
    "list_image_small": {"width": 400, "height": 300},
    "list_image_medium": {"width": 800, "height": 600},
    "hero_image": {"width": 1600, "height": 600},
}

Define widgets (admin interface). Note that images with the same aspect ratio might share widget:

WAGTAIL_EXACT_IMAGE_CROP_WIDGETS = {
    "avatar": {
        "title": "Avatar image",
        "description": "Used in listings and teasers",
        "presets": ["avatar"],
    },
    "medium_shot": {
        "title": "Medium shot image",
        "description": "Used in listings and teasers",
        "presets": ["medium_shot"],
    },
    "list_image": {
        "title": "List image",
        "description": "Used in listings and teasers",
        "presets": ["list_image_small", "list_image_medium"],
    },
    "hero_image": {
        "title": "Hero image",
        "description": "Large banner at top of page",
        "presets": ["hero_image"],
    },
}

Wagtail Exact Crop disables Wagtail's focal point editor by default. To use focal point and exact crops side by side, enable it explicitly:

WAGTAIL_EXACT_IMAGE_CROP_FOCAL_POINT_ENABLED = True

This setting only controls the focal point editor in the Wagtail admin. Existing focal point data is preserved either way and will still be submitted with the image form.

Exact crop is registered as a custom image filter, so you can use it in your templates like any other image filter. https://docs.wagtail.org/en/latest/extending/custom_image_filters.html

Just use the exact- prefix followed by the crop preset name to apply the crop:

{% load wagtailimages_tags %}

{% image some_image exact-avatar %}
{% image some_image exact-medium_shot %}
{% image some_image exact-list_image_small %}
{% image some_image exact-list_image_medium %}
{% image some_image exact-hero_image %}

Development and testing

Install the package with test dependencies:

uv venv
source .venv/bin/activate
pip install -e ".[test]"

Run the automated tests:

pytest

Demo project

The tests/test_project Django/Wagtail project can be used for manual testing and demonstration.

python tests/test_project/manage.py migrate
python tests/test_project/manage.py createsuperuser
python tests/test_project/manage.py runserver

Then open http://127.0.0.1:8000/admin/, upload an image, edit it, adjust the exact crop widgets, and save. The exact crop demo at http://127.0.0.1:8000/exact-crop/ renders the latest uploaded image using the documented exact-* filters. The focal point comparison page at http://127.0.0.1:8000/focal-point/ renders the same target sizes with Wagtail's fill-* filters.

Releasing

Releases are published to PyPI by GitHub Actions when a v* tag is pushed.

Update the project version in pyproject.toml.

git add pyproject.toml
git commit -m "Release 0.1.1"
git tag -a v0.1.1 -m v0.1.1
git push
git push origin v0.1.1

The Git tag should be the package version with a v prefix. For example, version = "0.1.1" in pyproject.toml is released with tag v0.1.1.

You can also create the GitHub Release in the web UI after pushing the tag. If you create the tag through the GitHub Release UI, make sure the version bump commit is already on the target branch.

To build and inspect the package locally:

uv build

This writes the release artifacts to dist/. Before publishing, inspect the generated files and verify the package data is included:

tar -tf dist/wagtail_exact_crop-*.tar.gz
unzip -l dist/wagtail_exact_crop-*.whl