imgflo 0.1: An image processing server and Flowhub runtime

At TheGrid we are in need for a flexible service for doing server-side image processing. So after some discussion at LGM in Leipzig, I started writing one based on GEGL, the image processing library that will power the upcoming GIMP 2.10 release. The library provides a demand-driven graph-based API , with a ton of operations included and support for GPU processing using OpenCL.


For creating image processing pipelines for the server, imgflo acts as a runtime for Flowhub, our open source visual programming IDE. It adds to the existing NoFlo browser, Node.js and MicroFlo microcontroller runtime targets, all possible thanks to the runtime-agnostic protocol.

The preview is live and changes whenever changes are made to the graph. This allows to quickly experiment and develop new graphs.


As a server, imgflo provides a simple HTTP API where you specify the input image as an URL, the graph to process it through and any parameters exposed on that graph.

Requests being made to the imgflo server HTTP API on demo page

Processed images are cached, so that subsequent request on the same url just returns the image out of the cache.
The git repository includes configuration and build setup for Heroku, so deploying an instance is a 5 minute job.


imgflo 0.1 is now minimally useful as image processing server, but there are many more enhancements on the todo list. Scalability and integration with NoFlo are two big topics, as as expanding the pool of available operations and graphs. Porting filters from GIMP to GEGL is a way of helping with the latter.

Additionally it would be interesting to provide a way of using imgflo with GIMP. First of all one could use graphs made with Flowhub via GEGL meta-operations. A more crazy idea is to integrate directly,  using Flowhub as a companion node-based editor.



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