Image Displayer

[Chase Preuninger]

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.

 

[mekane]

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.

 

[Chase Preuninger]

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

 

[Philipp]

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

 

[John B. Matthews]

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.

[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

 

[Roedy Green]

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.