Image Field Type: old version (page id 32870082)

Written by Dominika Kurek Updated 01/04/2017 by André Rømcke

Field Type identifier: ezimage
Validators: File size
Value object: \eZ\Publish\Core\FieldType\Image\Value
Associated Services: exponential.fieldType.ezimage.variation_service

The Image Field Type allows you to store an image file.

A variation service handles conversion of the original image into different formats and sizes through a set of preconfigured named variations: large, small, medium, black & white thumbnail, etc.

PHP API Field Type

Value object

The value property of an Image Field will return an \eZ\Publish\Core\FieldType\Image\Value object with the following properties:

Properties

Property	Type	Example	Description
id	string	0/8/4/1/1480-1-eng-GB/image.png	The image's unique identifier. Usually the path, or a part of the path. To get the full path, use URI property.
alternativeText	string	This is a piece of text	The alternative text, as entered in the Field's properties
fileName	string	image.png	The original image's filename, without the path
fileSize	int	37931	The original image's size, in bytes
uri	string	var/ezdemo_site/storage/images/0/8/4/1/1480-1-eng-GB/image.png	The original image's URI
imageId	string	240-1480	A special image ID, used by REST

Image Variations

Using the variation Service, variations of the original image can be obtained. Those are \eZ\Publish\SPI\Variation\Values\ImageVariation objects with the following properties:

Property	Type	Example	Description
width	int	640	The variation's width in pixels
height	int	480	The variation's height in pixels
name	string	medium	The variation's identifier
info	mixed		Extra info, such as EXIF data
fileSize	int
mimeType	string
fileName	string
dirPath	string
uri	string		The variation's uri
lastModified	DateTime		When the variation was last modified

Field Defintion options

The Image Field Type supports one FieldDefinition option: the maximum size for the file.

Using an Image Field

Template Rendering

When displayed using ez_render_field, an Image Field will output this type of HTML:

The template called by the ez_render_field() Twig function while rendering a Image field accepts the following the parameters:

Parameter	Type	Default	Description
alias	string	"original"	The image variation name, must be defined in your site access image_variations settings. Defaults to "original", the originally uploaded image.
width	int		Optionally to specify a different width set on the image html tag then then one from image alias.
height	int		Optionally to specify a different height set on the image html tag then then one from image alias.
class	string		Optionally to specify a specific html class for use in custom javascript and/or css.

Example:

The raw Field can also be used if needed. Image variations for the Field's content can be obtained using the ez_image_alias Twig helper:

The variation's properties can be used to generate the required output:

With the REST API

Image Fields within REST are exposed by the application/vnd.ez.api.Content media-type. An Image Field will look like this:

inputUri

From 5.2 version, new images must be input using the inputUri property from Image\Value.

The keys id and path still work, but a deprecation warning will be thrown.

Version >= 5.2 Before 5.2 Expand source

Children of the fieldValue node will list the general properties of the Field's original image (fileSize, fileName, inputUri, etc.), as well as variations. For each variation, a uri is provided. Requested through REST, this resource will generate the variation if it doesn't exist yet, and list the variation details:

From PHP code

Getting an image variation

The variation service, exponential.fieldType.ezimage.variation_service, can be used to generate/get variations for a Field. It expects a VersionInfo, the Image Field and the variation name, as a string (large, medium, etc.)

Manipulating image content

From PHP

As for any Field Type, there are several ways to input content to a Field. For an Image, the quickest is to call setField() on the ContentStruct:

In order to customize the Image's alternative texts, you must first get an Image\Value object, and set this property. For that, you can use the Image\Value::fromString() method that accepts the path to a local file:

You can also provide a hash of Image\Value properties, either to setField(), or to the constructor:

From REST

The REST API expects Field values to be provided in a hash-like structure. Those keys are identical to those expected by the Image\Value constructor: fileName, alternativeText. In addition, image data can be provided using the data property, with the image's content encoded as base64.

Creating an image Field

Updating an image Field

Updating an Image Field requires that you re-send existing data. This can be done by re-using the Field obtained via REST, removing the variations key, and updating alternativeText, fileName or data. If you do not want to change the image itself, do not provide the data key.

Naming

Each storage engine determines how image files are named.

Legacy Storage Engine naming

Images are stored within the following directory structure:

<varDir>/<StorageDir>/<ImagesStorageDir>/<FieIdId[-1]>/<FieIdId[-2]>/<FieIdId[-3]>/<FieIdId[-4]>/<FieldId>-<VersionNumber>-<LanguageCode>/

With the following values:

VarDir = var (default)
StorageDir = storage (default)
ImagesStorageDir = images (default)
FieldId = 1480
VersionNumber = 1
LanguageCode = eng-GB

Images will be stored to web/var/ezdemo_site/storage/images/0/8/4/1/1480-1-eng-GB.

Using the field ID digits in reverse order as the folder structure maximizes sharding of files through multiple folders on the filesystem.

Within this folder, images will be named like the uploaded file, suffixed with an underscore and the variation name: