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From thomas.dewe...@kodak.com
Subject Re: PNG transcoding time -- f(resulting file size)?
Date Mon, 03 Apr 2006 22:41:10 GMT
"Justin McCarthy" <justinamccarthy@gmail.com> wrote on 04/03/2006 04:19:22 
PM:

> >    Yah, the biggest problem is that the PNG encoder is 100% pure java 
and
> > the JPEG encoder is 100% native code.  You might try the new 
ImageWriter
> > stuff which would enable you to use the javax.imageio PNG encoder 
which I think
> > is native underneath.  This might be much faster.  Checking this is 
one of
> > the things on my TODO list.
> 
> Ok, that explains things. Thanks.

  FYI, if you check out the trunk from SVN you should be able to 
switch to the JIIO stuff by simply editing the file:
        
resources/META-INF/services/org.apache.batik.ext.awt.image.spi.ImageWriter

  So that 'org.apache.batik.ext.awt.image.codec.png.PNGImageWriter' is
commented out and 
 'org.apache.batik.ext.awt.image.codec.imageio.ImageIOPNGImageWriter'
is uncommented and retest.  I would test carefully as when this was
uncommented we had regressions in our tests, but it may be unimportant
differences.

> >    Essentially everything will transcoder much larger as PNG than JPEG
> > PNG is lossless and JPEG is lossy.
> 
> I've seen PNGs weigh in under JPEGs for primitive shapes -- corporate
> logos and such; my reasoning was that PNG does run-length encoding,
> making large homogenous areas highly compressable -- although now that
> I think about it, seems like JPEG does RLE as well <shrug>.  Encoder
> idiosyncrasies, I guess (I was thinking of .NET's native drawing
> libraries).
> 
> Anyway, thanks for sorting this out.  I'll start poking around the
> source a bit, see if I can begin to comprehend how we could get the
> native PNG encoding wired up.  If anyone else is interested in further
> investigation, let me know, and we can coordinate our efforts.
> 
> /Justin
> 
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