The OSGeo code sprint had some great discussion around map rendering.
This BOF is a follow up to explore:
1) Round extending the GeoTools rendering engine across a cluster.
2) The JAI-Ext improves JAI use for spatial data (support for nodata, performance, new operations). For more information see https://github.com/geosolutions-it/jai-ext/wiki
3) Use of JAI as an image processing engine - explore JAI migration/rewriting options with interested parties (JAI has been orphaned by Oracle)
4) JVM rendering performance has been bottle necked. Compare notes using marlin Java 2D implementation. For more information: https://github.com/bourgesl/marlin-renderer
Projects expressing interest include: GeoMesa, GeoTools, GeoServer, GeoWave, and uDig.