No reply on this, so I've just created issue 5651 so it doesn't get
lost. It would be nice if the GWT compiler could produce png image
bundles in compressed format.
Background: The png file format has support for the deflate algorithm
built-in, but png files don't *have* to use it. So some png files will
contain compressed data, while others will not. GWT with an
out-of-the-box JDK do not generate compressed png files.
http://code.google.com/p/google-web-toolkit/issues/detail?id=5651
Thanks,
Paul
On 03/11/10 00:13, Paul Robinson wrote:
I've just started using this colour picker:
http://code.google.com/p/auroris/wiki/ColorPicker
One of the warnings its documentation provides is that when you
compile it with GWT, the images it contains are compiled into a png
file that is about 1MB. Whereas, if you then open that file in any
image processing software and re-save it, it compresses down to around
110kb.
The problem is that during the compile, GWT's ImageBundleBuilder uses
javax.imageio.Imageio.write(BufferedImage, "png", outputStream), and
with an out-of-the-box JDK installation, the javax.imageio.Imageio
stuff does not support png compression. (png has support for the
deflate algorithm built-in, but it seems you don't *have* to use it
when writing out png files)
However, by installing an additional package to add to my JDK, I
managed to get a gwt compile to produce compressed png files:
http://download.java.net/media/jai-imageio/builds/release/1.1/INSTALL-jai_imageio.html#Manual
Some of my small png files got slightly bigger, but that 1MB png got
much smaller.
This is a known bug in the JDK, and there's a bug report here:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4829970
but that's a very old bug report, so may not be fixed any time soon.
Is this something that GWT could address, so that this would work
correctly out-of-the-box?
Thanks,
Paul
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