Package: django-stdimage
Django Standardized Image FieldThis package has been deprecated in favor ofdjango-pictures.Migration InstructionsFirst, make sure you understand the differences between the two packages and
how to serve images in a modern web application via thepicture-Element.Next, follow the setup instructions fordjango-pictures.Once you are set up, change your models to use the newPictureFieldand provide theaspect_ratiosyou'd like to serve. Do create migrations just yet.This step should be followed by changing your templates and frontend.
The new placeholders feature for local development should help you
to do this almost effortlessly.Finally, runmakemigrationsand replace theAlterFieldoperation withAlterPictureField.We highly recommend to use Django'simage_widthandimage_heightfields, to avoid
unnecessary IO. If you can add these fields to your model, you can use the following
snippet to populate them:importdjango.core.files.storagefromdjango.dbimportmigrations,modelsimportpictures.modelsfrompictures.migrationsimportAlterPictureFielddefforward(apps,schema_editor):forobjinapps.get_model("my-app.MyModel").objects.all().iterator():obj.image_width=obj.logo.widthobj.image_height=obj.logo.heightobj.save(update_fields=["image_height","image_width"])defbackward(apps,schema_editor):apps.get_model("my-app.MyModel").objects.all().update(image_width=None,image_height=None,)classMigration(migrations.Migration):dependencies=[('my-app','0001_initial'),]operations=[migrations.AddField(model_name="mymodel",name="image_height",field=models.PositiveIntegerField(editable=False,null=True),),migrations.AddField(model_name="mymodel",name="image_width",field=models.PositiveIntegerField(editable=False,null=True),),migrations.RunPython(forward,backward),AlterPictureField(model_name="mymodel",name="image",field=pictures.models.PictureField(aspect_ratios=["3/2","3/1"],breakpoints={"desktop":1024,"mobile":576},container_width=1200,file_types=["WEBP"],grid_columns=12,height_field="image_height",pixel_densities=[1,2],storage=django.core.files.storage.FileSystemStorage(),upload_to="pictures/",verbose_name="image",width_field="image_width",),),]Why would I want this?This is a drop-in replacement for theDjango ImageFieldthat provides a standardized way to handle image uploads.
It is designed to be as easy to use as possible, and to provide a consistent interface for all image fields.
It allows images to be presented in various size variants (eg:thumbnails, mid, and hi-res versions)
and it provides a way to handle images that are too large with validators.FeaturesDjango Standardized Image Field implements the following features:Django-Storagescompatible (eg: S3, Azure, Google Cloud Storage, etc)Resizes images to different sizesAccess thumbnails on model level, no template tags requiredPreserves original imagesCan be rendered asynchronously (ie as aCelery job)Restricts acceptable image dimensionsRenames a file to a standardized name format (using a callableupload_tofunction, see below)InstallationSimply install the latest stable package using the following command:pipinstalldjango-stdimage# orpipenvinstalldjango-stdimageand add'stdimage'toINSTALLED_APPs in your settings.py, that's it!UsageNow it's instally you can use either:StdImageFieldorJPEGField.StdImageFieldworks just like Django's ownImageFieldexcept that you can specify different size variations.TheJPEGFieldis identical to theStdImageFieldbut all images are
converted to JPEGs, no matter what type the original file is.VariationsVariations are specified within a dictionary. The key will be the attribute referencing the resized image.
A variation can be defined both as a tuple or a dictionary.Example:fromdjango.dbimportmodelsfromstdimageimportStdImageField,JPEGFieldclassMyModel(models.Model):# works just like django's ImageFieldimage=StdImageField(upload_to='path/to/img')# creates a thumbnail resized to maximum size to fit a 100x75 areaimage=StdImageField(upload_to='path/to/img',variations={'thumbnail':{'width':100,'height':75}})# is the same as dictionary-style callimage=StdImageField(upload_to='path/to/img',variations={'thumbnail':(100,75)})# JPEGField variations are converted to JPEGs.jpeg=JPEGField(upload_to='path/to/img',variations={'full':(None,None),'thumbnail':(100,75)},)# creates a thumbnail resized to 100x100 croping if necessaryimage=StdImageField(upload_to='path/to/img',variations={'thumbnail':{"width":100,"height":100,"crop":True}})## Full ammo here. Please note all the definitions below are equalimage=StdImageField(upload_to='path/to/img',blank=True,variations={'large':(600,400),'thumbnail':(100,100,True),'medium':(300,200),},delete_orphans=True)To use these variations in templates usemyimagefield.variation_name.Example:<ahref="{{ object.myimage.url }}"><imgalt=""src="{{ object.myimage.thumbnail.url }}"/></a>Upload to functionYou can use a function for theupload_toargument. Using [Django Dynamic Filenames][dynamic_filenames].[dynamic_filenames]:https://github.com/codingjoe/django-dynamic-filenamesThis allows images to be given unique paths and filenames based on the model instance.Examplefromdjango.dbimportmodelsfromstdimageimportStdImageFieldfromdynamic_filenamesimportFilePatternupload_to_pattern=FilePattern(filename_pattern='my_model/{app_label:.25}/{model_name:.30}/{uuid:base32}{ext}',)classMyModel(models.Model):# works just like django's ImageFieldimage=StdImageField(upload_to=upload_to_pattern)ValidatorsTheStdImageFielddoesn't implement any size validation out-of-the-box.
However, Validation can be specified using the validator attribute
and using a set of validators shipped with this package.
Validators can be used for both Forms and Models.Examplefromdjango.dbimportmodelsfromstdimage.validatorsimportMinSizeValidator,MaxSizeValidatorfromstdimage.modelsimportStdImageFieldclassMyClass(models.Model):image1=StdImageField(validators=[MinSizeValidator(800,600)])image2=StdImageField(validators=[MaxSizeValidator(1028,768)])CAUTION:The MaxSizeValidator should be used with caution.
As storage isn't expensive, you shouldn't restrict upload dimensions.
If you seek prevent users form overflowing your memory you should restrict the HTTP upload body size.Deleting imagesDjangodropped supportfor automated deletions in version 1.3.Since version 5, this package supports adelete_orphansargument. It will delete
orphaned files, should a file be deleted or replaced via a Django form and the object with
theStdImageFieldbe deleted. It will not delete files if the field value is changed or
reassigned programatically. In these rare cases, you will need to handle proper deletion
yourself.fromdjango.dbimportmodelsfromstdimage.modelsimportStdImageFieldclassMyModel(models.Model):image=StdImageField(upload_to='path/to/files',variations={'thumbnail':(100,75)},delete_orphans=True,blank=True,)Async image processingTools like celery allow to execute time-consuming tasks outside of the request. If you don't want
to wait for your variations to be rendered in request, StdImage provides you the option to pass an
async keyword and a 'render_variations' function that triggers the async task.
Note that the callback is not transaction save, but the file variations will be present.
The example below is based on celery.tasks.py:fromdjango.appsimportappsfromceleryimportshared_taskfromstdimage.utilsimportrender_variations@shared_taskdefprocess_photo_image(file_name,variations,storage):render_variations(file_name,variations,replace=True,storage=storage)obj=apps.get_model('myapp','Photo').objects.get(image=file_name)obj.processed=Trueobj.save()models.py:fromdjango.dbimportmodelsfromstdimage.modelsimportStdImageFieldfrom.tasksimportprocess_photo_imagedefimage_processor(file_name,variations,storage):process_photo_image.delay(file_name,variations,storage)returnFalse# prevent default renderingclassAsyncImageModel(models.Model):image=StdImageField(# above task definition can only handle one model object per image filenameupload_to='path/to/file/',# or use a functionrender_variations=image_processor# pass boolean or callable)processed=models.BooleanField(default=False)# flag that could be used for view querysetsRe-rendering variationsYou might have added or changed variations to an existing field. That means you will need to render new variations.
This can be accomplished using a management command.pythonmanage.pyrendervariations'app_name.model_name.field_name'[--replace][-i/--ignore-missing]Thereplaceoption will replace all existing files.
Theignore-missingoption will suspend 'missing source file' errors and keep
rendering variations for other files. Otherwise, the command will stop on first missing file.