How to work with images using imgfn

This page explains how to work with images using imgfn  templating functions in template scripts. With imgfn you can get an image from any JCR workspace. 

If you manage your images with the Magnolia Digital Asset Management module, we recommend using damfn. For more information, see working with images using damfn . 

Imaging modules

If you use a Magnolia bundle, the required and optional modules are already included.

If you created a custom webapp, add the following modules in the pom file of the webapp of your bundle. The modules may have dependencies to other modules but these dependencies are handled by Maven dependency management.

Required modules

Modules required for basic image operations.

Optional modules

Modules required when using size variations of an image. Recommended.

Uploading the image with a basic upload field

With a basic upload field you can upload an image directly to the node of your context. When saving the data of the dialog, Magnolia creates a subnode of the node of your context and stores the binary data of the image as property of the subnode. 

• If the dialog is for a Component, the system creates a subnode of the component node.
• If the dialog is for a an item of a content app, the system creates a subnode of the content item node.

Example - code fragment from a dialog definition

Form:
  tabs:
    - name: tabImage
      fields:
        - name: image
          class: info.magnolia.ui.form.field.definition.BasicUploadFieldDefinition
          binaryNodeName: myNode

In the dialog definition, you can define the value of the binaryNodeName property  (in the example the value is myNode). Keep in mind that you must know the name of this subnode to render the image later on.

You can check the JCR node structure in in the JCR Browser app.

Displaying an image variation using imgfn

Using imgfn, you can create a link to an image stored in any workspace as long as you know the path to the node which stores the binary data of the image.

Look at the screenshot above showing the JCR browser. It highlights the subnode of a component node. Within the rendering context of a component template script you have the  content object which is the component node. In the screenshot above, the node with the name 0 is the content object.

To display an image, you must get the subnode of content and pass it as argument to the imgfn templating function. You can use the same method to get the original version of the image and to get a variation.

[#assign binaryNode = cmsfn.asJCRNode(content).getNode('myNode') /]
[#assign imgLink = imgfn.getImageVariationLinkFromBinary(binaryNode,'original') /]
[#assign imgLink240 = imgfn.getImageVariationLinkFromBinary(binaryNode,'240') /]

<div>
    <span>The default image</span><br/>
    <img src="${imgLink}"><br/>
    <span>Image variation 240</span><br/>
    <img src="${imgLink240}">
</div>

• Line: Get the subnode which contains the binary data. You need to know the subnode name, myNode in the example.
• Line 2, 3: Create a link to the image. Use original to get the original size of the uploaded image.
• Line 2, 3: Create a link to the image. Use 240 to get a link to an image variation named 240.
  • Make sure the image variation you want to use is configured in your site theme. Each variation should be a node under <my-theme>/imaging/variations. 

Here is the rendered result of the template script snippet above: