Re: ImageIO on in-memory byte array

From:

Knute Johnson <nospam@rabbitbrush.frazmtn.com>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 20 Oct 2006 10:44:19 -0700

Message-ID:

<1U7_g.111$yy2.74@newsfe11.phx>

roger.books wrote:

I'm pulling it in from a custom format a bank is using. It's a small
header
and 50K images concatenated. The image offsets, sizes, and other
information is stored in an XML file. I guess I could make an input
stream
that took file name, offfset, and bytes.

Can anyone recommend a resource that shows how to make an input stream?
I _think_ it is just implementing the interface. Is that correct?

Roger

Knute Johnson wrote:

Mike Schilling wrote:

"roger.books" <roger.books@gmail.com> wrote in message
news:1161286240.031414.165370@i3g2000cwc.googlegroups.com...

I have an application that reads TIFFs from a file that is a
concatenation of TIFFs along with some special headers. For this
question I have the TIFF in a byte array.

I have installed the jai/ImageIO libs from Sun,
ImageIO.getReaderFormatNames() shows TIFF as one of the options.

I can write out the TIFF file and read it in using:

File f = new File("c:\images\myimage.tiff");
BufferedImage bi = ImageIO.read(f);

and write out the converted file using ImageIO.write()

however, I need to do 50,000 images and would prefer to skip the
intermediate file. Does anyone have any pointers on how to do this?

Make an input stream from the byte array and feed that to ImageIO.read().

What is the format of the TIFF byte array? Could you actually be
reading it in as an image? That would save you two conversion steps.

The docs say, "Applications that need to define a subclass of
InputStream must always provide a method that returns the next byte of
input."

But what I might do is write a class that reads the file and returns an
array of BufferedImages. Then manipulate them as desired and save them
in whatever format you want.

You know the sizes of the images, so read them into a byte[], manipulate
them, create a ByteArrayInputStream from the byte[], and then use
ImageIO to read the TIFF image from BAIS. Buffer the disk I/O and it
should be plenty fast.

--

Knute Johnson
email s/nospam/knute/