Adapters for RRD4J to create SVG images

There are three flavors here, with different dependencies:

• SVGImageWorker: jfreesvg dependency (50KB, GPLv3)
• BatikSVGImageWorker: Apache Batik dependency (4MB, Apache)
• SimpleSVGImageWorker: no dependency (Apache)

See below for Apache Batik and Simple flavors.

Benefits

• Faster server-side rendering
• Greatly reduced server-side memory usage
• Crisper, scaleable images and text
• Smaller image files (especially if gzipped)
• Much less bandwidth usage if images are gzipped in-flight
• Rendered images almost identical to the PNG versions

jfreesvg Adapter

Requires Java 8 or higher, RRD4J 3.10 or higher and JFreeSVG.

Note that JFreeSVG says Java 11 is required but that's apparently only for modules, works fine with Java 8 when built from source.

Pro: Only 50KB. Con: GPLv3

Usage Example

No ImageIO/BufferedImage/ImageWriter required!

RRDGraph graph = new RrdGraph(graphdef, new SVGImageWorker(width, height));
outputstream.write(graph.getRrdGraphInfo().getBytes());

DEMO

Apache Batik Adapter

An equivalent adapter for Apache Batik is in BatikSVGImageWorker.java. Java 8 or higher.

Specific Batik jars/modules required, if you don't want to just use the 4 MB batik-all.jar, these total about 1 MB, or "only" 20x larger than jfreesvg:

• batik-awt-util.jar
• batik-constants.jar
• batik-dom.jar
• batik-ext.jar
• batik-i18n.jar
• batik-svggen.jar
• batik-util.jar
• batik-xml.jar

Note that some features may require additional jars, untested.

Pro: Apache licensed. Con: 4MB (or 1MB if you use only the jars listed above)

Usage Example

RRDGraph graph = new RrdGraph(graphdef, new BatikSVGImageWorker(width, height));
outputstream.write(graph.getRrdGraphInfo().getBytes());

Simple No-Dependency Adapter

An equivalent adapter without dependencies is in SimpleSVGImageWorker.java, together with SimpleSVGGraphics2D and SimpleSVGMaker. Java 8 or higher.

The Simple version supports everything rrd4j needs, Apache licensed, about 1/4 of the size of jfreesvg, without any external dependencies. Unsupported Graphics2D methods and features will throw UnsupportedOperationExceptions.

Pros: Apache licensed, only 10KB. Con: May not support all use cases; not all Graphics2D methods are implemented.

Usage Example

RRDGraph graph = new RrdGraph(graphdef, new SimpleSVGImageWorker(width, height));
outputstream.write(graph.getRrdGraphInfo().getBytes());

License

All flavors are Apache 2.0 (same as RRD4J)