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Chase Preuninger - 08 May 2008 21:30 GMT

I want to figure out how to read a JPG file by just using the read
method in the InputStream class then I want to create a GUI component
that can display it.

1) How are the bytes formatted in a JPG file?
2) What is the best way to color individual pixels in a JComponent.

Please don't tell me to just use ImageIO and to draw it using a
Graphics object because I know how to do that.

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mekane - 08 May 2008 21:36 GMT

> I want to figure out how to read a JPG file by just using the read
> method in the InputStream class then I want to create a GUI component
> that can display it.
>
> 1) How are the bytes formatted in a JPG file?

Have you Googled for the JPEG spec?

> 2) What is the best way to color individual pixels in a JComponent.
>
> Please don't tell me to just use ImageIO and to draw it using a
> Graphics object because I know how to do that.

If I were you I would use the ImagIO packa-- oh, yeah, never mind. Good
luck with your project.

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Chase Preuninger - 08 May 2008 22:00 GMT

I'm just intrested in seeing if I can do it.

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Lew - 09 May 2008 00:29 GMT

> I'm just intrested in seeing if I can do it.

Besides the excellent advice already proffered of looking up the JPEG file
layout online, I suggest that you only need to post to one newsgroup,
especially given the huge overlap in readership among the three to which you
cross-posted. While cross-posting is better than multi-posting, it is at best
tolerated and at best not helpful to the poster. It's really sufficient to
ask your question once in these groups.

If you really must demean your message and diminish your standing by
cross-posting, it helps to set follow-up (f-u) to a single newsgroup, as here
with clj.help.

<http://www.jpeg.org/jpeg/index.html>
<http://en.wikipedia.org/wiki/JPEG>

GIYF.
WIYF.

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Lew

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Lew - 09 May 2008 00:30 GMT

Chase Preuninger wrote:

>> I'm just intrested in seeing if I can do it.

Signature

Lew

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Philipp - 09 May 2008 13:41 GMT

> 1) How are the bytes formatted in a JPG file?

In case you are also interested in other formats, see this very useful page:
http://www.martinreddy.net/gfx/2d-hi.html

HTH Phil

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John B. Matthews - 10 May 2008 04:14 GMT

In article
<76f67313-1255-4056-b072-8dc634fa0c42@c65g2000hsa.googlegroups.com>,

> I want to figure out how to read a JPG file by just using the read
> method in the InputStream class then I want to create a GUI component
[quoted text clipped - 4 lines]
>
> [elided]

Just to get started, use one of the ImageIO.read() methods to get your
image into a BufferedImage. Then call getRaster() and have fun with the
raster's numerous setXXX methods. Then override paintComponent() in
whatever Component you extend:

protected void paintComponent(Graphics g) {
g.drawImage(bufferedImage, 0, 0, this);
}

John

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John B. Matthews
trashgod at gmail dot com
home dot woh dot rr dot com slash jbmatthews

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Roedy Green - 10 May 2008 09:03 GMT

On Thu, 8 May 2008 13:30:10 -0700 (PDT), Chase Preuninger
<chasepreuninger@gmail.com> wrote, quoted or indirectly quoted someone
who said :

>1) How are the bytes formatted in a JPG file?

See http://mindprod.com/jgloss/jpg.html
http://mindprod.com/jgloss/gif.html
and follow the links.

If all you want is size info quickly, download
http://mindprod.com/products1.html#COMMON11
and look at ImageInfo

If you just want to mess around at a low level, tackle GIF or PNG
first. They are much simpler formats.

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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