senselogic.sitevision.api.render

Interface ImageLinkRenderer

@Requireable(value="ImageLinkRenderer")
public interface ImageLinkRenderer

ImageLinkRenderer is a stateful utility interface that combines an ImageRenderer and a LinkRenderer to render valid image links.

Using the ImageLinkRenderer is pretty straightforward. All setup and state are maintained in an ImageRenderer instance and an LinkRenderer instance that both can be retrieved via their corresponding getters. Conceptually you would typically use ImageLinkRenderer like this:

1. Get the ImageLinkRenderer
2. Fetch the LinkRenderer used by the image link renderer
3. Init the link renderer and set the target (see LinkRenderer)
4. Fetch the ImageRenderer used by the image link renderer
5. Init the image renderer and set the image (see ImageRenderer)
6. Do render

When you have rendered once, you can re-use the renderers until you are done. Something like:

1. Update the image renderer with a new image
2. Update the link renderer with a new target
3. Do render.

Example of how this strategy could be implemented in Velocity:
(You want to do a simple thumbnail listing of some image nodes in a collection/iterator "$images", and each thumbnail should be linked to the original image (and opened in a new window)

   ## Get the ImageLinkRenderer
   #set ($imageLinkRenderer = $sitevisionUtils.imageLinkRenderer)

   ## Fetch the ImageRenderer and apply an image scaler (200x100 px)
   #set ($imageScaler = $sitevisionUtils.getImageScaler(200, 100))
   #set ($imageRenderer = $imageLinkRenderer.imageRenderer)
   $imageRenderer.setImageScaler($imageScaler)

   ## Fetch the LinkRenderer and ensure links will be opened in a new window
   #set ($linkRenderer = $imageLinkRenderer.linkRenderer)
   $linkRenderer.forceOpenNewWindow()

   ## Iterate through images and render them
   <ul style="list-style:none">
   #foreach ($image in $images)
      ## Load an image (that will be rendered as a 200x100 thumbnail)
      $imageRenderer.update($image)

      ## Link the image
      $linkRenderer.update($image)

      <li>
         ## Render the image link (i.e. a thumbnail image linked to the original image)
         $imageLinkRenderer.render()
      </li>
   #end
   </ul>
 

Validation Note! Some validation tools consider image links to be invalid if the linked content (i.e. in this case an <img> element) does not have a textual representation (i.e. the alt attribute of the <img> element is empty). In order to minimize work to encompass this, the ImageRenderer.forceUseAutoDescription() is initially invoked for the ImageRenderer used by the ImageLinkRenderer.

Thread Note! The render method is NOT thread safe! During execution of the render method the ImageLinkRenderer might temporarily modify the state of the LinkRenderer and/or the ImageRenderer. In other words: if two threads simultaneously executes the render method on the SAME ImageLinkRenderer instance, the rendered result might differ. This is in almost all cases nothing you need to worry about, unless your portlet or servlet actually creates a separate Thread and starts it. If so - ensure all your created threads creates and uses their own ImageLinkRenderer instance!

An instance of the Sitevision class implementing this interface can be obtained via Utils.getImageLinkRenderer(). See Utils for how to obtain an instance of the Utils interface.

Since:

Sitevision 2.6.2_04

Author:

Magnus Lövgren

See Also:

LinkRenderer, ImageRenderer

Method Summary

Modifier and Type	Method and Description
ImageRenderer	getImageRenderer() Returns the ImageRenderer instance used by this image link renderer to control (linked) image behaviour.
LinkRenderer	getLinkRenderer() Returns the LinkRenderer instance used by this image link renderer to control linking behaviour.
String	render() Builds a html link based on current state of the link renderer and the image render.

Method Detail

getLinkRenderer

LinkRenderer getLinkRenderer()

Returns the LinkRenderer instance used by this image link renderer to control linking behaviour.

Returns:

the LinkRenderer instance used by this image link renderer

See Also:

LinkRenderer

getImageRenderer

ImageRenderer getImageRenderer()

Returns the ImageRenderer instance used by this image link renderer to control (linked) image behaviour.

Note! The useAutoDescription is initially set to true when the ImageRenderer instance is created by this image link renderer, see validation note above.

Returns:

the ImageRenderer instance used by this image link renderer

See Also:

ImageRenderer

render

String render()

Builds a html link based on current state of the link renderer and the image render.

Note! The render method is not thread safe, see thread note above.

Returns:

a html link, ready to print out on a page