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Posted to user@struts.apache.org by ron1 <ro...@gmx.net> on 2004/07/27 10:28:55 UTC
not quite struts: handling Images
Hi -
after spending much time wondring through the JAI API I thought maybe
one of you guys can help me:
I need a very simple:
1. upload-image (jpg/gif)
2. getProps (size, width)
3. resize
4. save JPG with custom compression.
The upload is done via FormFile, so I have the InputStream - all the
rest via Java API - and I have no clue of where to get started :-(
Cheers,
Ron
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Re: not quite struts: handling Images
Posted by Koon Yue Lam <ki...@gmail.com>.
Hi all !
I have similar problem to ron1 and these mails really help !
However if I want to extract the exif metadata of JPEG, can it be done
in Java without third party component?
Regards
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Re: not quite struts: handling Images
Posted by Kris Schneider <kr...@dotech.com>.
One thing to keep in mind with ImageIO and a long-running process, like an app
server, is its potential use of a disk-based cache. You may end up with lots of
temporary files that will only be removed if the VM exits normally. See:
http://java.sun.com/j2se/1.4.2/docs/api/java/io/File.html#deleteOnExit()
There's also this interesting bug:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4513817
To disable the disk-based cache in favor of a memory-based cache, use
ImageIO.setUseCache(false).
Once you have a BufferedImage, one way to resize it is with AffineTransformOp:
http://java.sun.com/j2se/1.4.2/docs/api/java/awt/image/AffineTransformOp.html
http://javaalmanac.com/egs/java.awt.image/CreateTxImage.html
As for saving with custom compression, here's something I've used before:
protected void writeImage(RenderedImage image, OutputStream out) throws
IOException {
ImageOutputStream imageOut = ImageIO.createImageOutputStream(out);
ImageWriter imageWriter =
(ImageWriter)ImageIO.getImageWritersByFormatName("jpeg").next();
imageWriter.setOutput(imageOut);
ImageWriteParam writeParam = imageWriter.getDefaultWriteParam();
writeParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
writeParam.setCompressionType("JPEG");
writeParam.setCompressionQuality(1);
imageWriter.write(null, new IIOImage(image, null, null), writeParam);
}
Quoting Mark Lowe <ma...@boxstuff.com>:
> Not sure about the resize and save (3-4) but the rest i use for
> ensuring users dont upload any old sizes..
>
>
> java.io.ByteArrayInputStream;
> java.awt.image.BufferedImage;
> javax.imageio.ImageIO;
>
> byte[] image = form.getImage().getFileData();
> ByteArrayInputStream stream = new ByteArrayInputStream(image);
> BufferedImage img = ImageIO.read(stream);
>
> BufferedImage has getWidth and getHeight
>
> Perhaps also better not to use getFileData on the formFile, and use the
> getInputStream method instead as its less heavy..
>
> Mark
>
> On 27 Jul 2004, at 10:28, ron1 wrote:
>
> > Hi -
> > after spending much time wondring through the JAI API I thought maybe
> > one of you guys can help me:
> > I need a very simple:
> > 1. upload-image (jpg/gif)
> > 2. getProps (size, width)
> > 3. resize
> > 4. save JPG with custom compression.
> > The upload is done via FormFile, so I have the InputStream - all the
> > rest via Java API - and I have no clue of where to get started :-(
> > Cheers,
> > Ron
--
Kris Schneider <ma...@dotech.com>
D.O.Tech <http://www.dotech.com/>
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Re: not quite struts: handling Images
Posted by Mark Lowe <ma...@boxstuff.com>.
Not sure about the resize and save (3-4) but the rest i use for
ensuring users dont upload any old sizes..
java.io.ByteArrayInputStream;
java.awt.image.BufferedImage;
javax.imageio.ImageIO;
byte[] image = form.getImage().getFileData();
ByteArrayInputStream stream = new ByteArrayInputStream(image);
BufferedImage img = ImageIO.read(stream);
BufferedImage has getWidth and getHeight
Perhaps also better not to use getFileData on the formFile, and use the
getInputStream method instead as its less heavy..
Mark
On 27 Jul 2004, at 10:28, ron1 wrote:
> Hi -
> after spending much time wondring through the JAI API I thought maybe
> one of you guys can help me:
> I need a very simple:
> 1. upload-image (jpg/gif)
> 2. getProps (size, width)
> 3. resize
> 4. save JPG with custom compression.
> The upload is done via FormFile, so I have the InputStream - all the
> rest via Java API - and I have no clue of where to get started :-(
> Cheers,
> Ron
>
>
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> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
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