com.adobe.cq.gfx

Interface Gfx

public interface Gfx

Graphics rendering service.

A Plan describes the rendering operations. These follow the Scene7 Image Serving Protocol. Different Renderer implementations can be active and differ in the supported set of operations or input file formats. The best available renderer will be picked depending on the plan.

General principles

• completely descriptive
  • makes no assumption about the actual implementation
  • allows for optimizations (examples: tile-based processing, use of a pre-created file with already scaled layers (pyramid tiff), reorganization of operations)
• extensible
  • map-like interface, operation names are strings
  • conceptually not restricted to 2D image rendering, could apply to 3D, audio, video or any asset processing as well (special commands would indicate that, but "Plan" data structure identical)
• input
  • referenced files in the JCR repository (usually using "src" attributes)
  • or plain drawing operations from scratch
  • specific renderer define what source formats are supported and what mechanism might be used to get an image rendition
  • referenced files in the resource tree (usually using "src" attributes, usually JCR) can have rendering operations attached ("modifiers"), these will be automatically applied
• output
  • a binary stream of a serialized image file
  • allows to store it back in the repository or stream it out over HTTP

Example usage

Resize an image from the repository and output it as png file:

     // build a plan from scratch
     Plan plan = gfx.createPlan();

     // single asset as source (single layer only)
     plan.layer(0).set("src", "/content/dam/asset.jpg");

     Plan.Map view = plan.view();
     // define target size
     view.set("wid", 300);
     view.set("hei", 200);
     // png format
     view.set("fmt", "png");

     InputStream in;
     try {
         // start rendering
         in = gfx.render(plan, resourceResolver);
         // use stream to store in repository or stream as servlet response
         // ...
     } finally {
         // ensure the stream is closed (to clean up temporary files etc.)
         IOUtils.closeQuietly(in);
     }
 

Method Summary

Modifier and Type	Method and Description
Plan	createPlan() Create an empty plan that can be set up from scratch.
java.io.InputStream	render(Plan plan, ResourceResolver resolver) Renders the given plan and returns a binary file stream, typically an image file format, depending on the plan.

Method Detail

createPlan

Plan createPlan()

Create an empty plan that can be set up from scratch.

Returns:

an empty rendering plan

render

java.io.InputStream render(Plan plan,
                           ResourceResolver resolver)

Renders the given plan and returns a binary file stream, typically an image file format, depending on the plan.

Parameters:

plan - describes the rendering operations

resolver - a resource resolver to access files referenced in the plan

Returns:

A binary file stream, typically an image file format. Callers must ensure that the InputStream is closed after usage. If the plan cannot be rendered, null will be returned.