Re: PNG support needed?

[Sascha Brawer]

Chris Nokleberg <address@hidden> wrote on Thu, 11 Jul 2002 13:39:22 -0700:

>I have a Java 1.1-compatible LGPL PNG decoder that I'd be willing to
>adapt as necessary, if it hasn't been done yet. See
>  http://sixlegs.com/software/png/

Thank you, Chris, for offering your help!

What do people think about supporting the Java Image I/O API
(javax.imageio.*, [1]) in Classpath (or Classpath Extensions)?

Advantages, IMHO:

- javax.imageio is a clean framework for supporting various image formats.
  Supporting PNG via javax.imageio would be cleaner than adding it
  directly into Classpath

- Sun made javax.imageio part of the Java Standard Edition 1.4, so we'll
  have to support Image I/O anyway, sooner or later

- people like Chris could contribute en-/decoders that work on any JVM,
  regardless of whether the JVM is based on Classpath or not


Disadvantages:

- we have no implementation of javax.imageio at the current time


If people agree that javax.imageio is the way to go, we could ask Chris
to package the PNG ImageReader as a plug-in according to Sun's "Service
Provider Interface" (see [2] - [4], and the javax.imageio.spi JavaDoc).

Ideally, Chris could make sure that his/her plug-in gives exactly the
same results as the PNG implementation in the current JDK.  For image
metadata, one could e.g. write a test suite that extracts the metadata
for each image in the PNG test suite. The results then should be
identical with the GNU and the Sun implementations.

What's your opinion?

-- Sascha


[1] http://java.sun.com/j2se/1.4/docs/guide/imageio/

[2] http://java.sun.com/j2se/1.4/docs/guide/imageio/spec/extending.fm1.html

[3] http://java.sun.com/j2se/1.4/docs/api/javax/imageio/metadata/doc-
files/standard_metadata.html

[4] http://java.sun.com/j2se/1.4/docs/api/javax/imageio/metadata/doc-
files/png_metadata.html