FreeHEP - Vector Graphics

Frequently Asked Questions (FAQ)


The vectorgraphics formats are distributed as separate jar files. I merged the jar files into one, but now I only see a few (or no) formats appear the ExportDialog option box. Where did the other formats go?

Every format registers itself as an ExportFileType with a lookup service, so that a program can find ExportFileTypes for a particular format. The registration is done by scanning each of the jar files on the classpath for the file META-INF/services/org.freehep.util.export.ExportFileType. This file contains the names of all the ExportFileTypes it should register, normally only one per jar file, but sometimes more, in the case of PS and EPS for instance.

If you merge all the jar files into one, you should also make a META-INF/services/org.freehep.util.export.ExportFileType file with ALL the formats in it.


PostScript and PDF can only reduce the clipping region. Is there a way in my java program to enlarge the region and still output correct PostScript and PDF?

Indeed in PostScript and PDF one can only reduce the clipping region. VectorGraphics has no protection for you setting a larger region and exporting to PostScript or PDF. However, both format can save the graphics state, reduce the clipping region and then restore the graphics state (including the initially larger clipping region).

You do not have direct control over save/restore, but creating a sub-graphics context is used to do a save/restore, as shown in the code below:

... large (or no) clipping exists in context g.

Graphics2D tempg = g.create();
tempg.clipRect(100, 100, 200, 200);

... draw stuff with smaller clipping


... large (or no) clipping exists in context g.

Note that it is important to call tempg.dispose(); at the end, otherwise the newly created graphics object will remain as a memory leak.