Handling images of more than 64M

[shefukul]

Hello all,

First i must admit that i have been programming is java for quite a time but am new to java2d or graphics.
I got confused of where i should place this question as i m using jogl.

My problem is this:

I have 3 files of .geo extension each of 492849281. The files consist of red,green and blue bands.
I have successfully manged to create a 5125123 file and display it, in crudest way possible…
The problem appears when i try managing the entire file 492849283.,Which amounts to around 72M if i m correct.
I have to scale this entire image to 512*512 for which i need to have this entire image once.
Is there any efficient way of placing these raw bytes into a bufferedImage which i can then convert to opengl texture?

The maximum size of the heap is 66M and i have tried using with java’s -Xm options.
of course i got stuck with OutOfMemoryError.
I was wondering whether i could divide the images into parts,scale it and then display it?

Actually i tried displaying 2464*2464,without scaling, in vain
Any ideas?

Regards.
shefali

[tusaki]

you could try to use supply a ImageReadParam to imageio.

http://java.sun.com/j2se/1.4.2/docs/guide/imageio/spec/apps.fm3.html#998328

…
More control may be obtained by supplying the read method with an additional parameter of type ImageReadParam. An ImageReadParam allows the application to specify a destination image in which the decoded image data should be stored, allowing better control over memory use. It also allows a region of interest to be specified, as well as subsampling factors that may be used to obtain a scaled-down version of the image.

When a source region is set, the reader plug-in will attempt to decode only the desired region, to the extent that the file format allows partial decoding. In any case, no pixels outside the region will appear in the output. This capability makes it possible to work with extremely large images in a limited amount of memory.
…

it specifically mentions memory usage. I haven’t used it myself though, but it’s worth having a look.

[CaptainJester]

Are you sure that you tried the -X options correctly?

-Xmx256M

will give you 256MB of memory, most of which can be used for the heap.

[shefukul]

Hello,

I did that as soon as i knew i could.
It helped to some extend but didnt actually solve the issue.
When i added some more code to it, like code to scale the image the problem persisted.
When i tried using this call for smaller images it gave BufferUnderFlow…
i got confused !!!
I think i may find a solution, dunno how, but i wont have chance to try anything new untill this weekend ends.

[Jeff]

For anything this big Id strongly suggest you use JAI which is intelligent about breaking images down into tiles.