When using the shaded version of cantaloupe.jar, JBIG and JP2 images in a PDF do not render

[cmhdave]

We've found that when you have a PDF with embedded images that were encoded with JBIG or with JP2, the shaded cantaloupe.jar can't find the org.apache.pdfbox:jbig2-imageio library. Similarly we can't get jai-imageio-jpeg2000 to work in the PDFs. I am able to get them to work by adding the jars independently to the classpath on startup like so

-cp jai-imageio-core.jar:jai-imageio-jpeg2000.jar:jbig2-imageio.jar:delegate.jar:cantaloupe.jar

Attached is a PDF you can test with.
index.pdf

[cmhdave]

Adding this here on how to add plugins to a JAR

https://docs.oracle.com/javase/8/docs/technotes/guides/imageio/spec/extending.fm2.html

I just don't want to lose it. I'll take a look at how it might be done during a build process when creating the shaded jar

[cmhdave]

Ah, I understand the issue now. The jbig2-imageio library comes with a file in META-INF/services in the jar called META-INF/services/javax.imageio.spi.ImageReaderSpi but you would potentially have many of those based on the different plugins that implement that interface. Hence including multiple ImageIO plugins in a shaded JAR presents a problem.

This similar issue opened on the jai-imageio project suggests that the Maven Shade plugin should handle this but you have explicitly defined <exclude>META-INF/services/javax.imageio.*</exclude>. Were there other issues present when this wasn't explicitly excluded?

[adolski]

This must have got broken in the war-to-jar switch. I don't remember why the javax.imageio.* services were being excluded. It should be fixed now, and hopefully the fix didn't break something else.