Path: utzoo!attcan!uunet!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!usc!ucsd!ucbvax!bloom-beacon!ZIA.AOC.NRAO.EDU!cflatter
From: cflatter@ZIA.AOC.NRAO.EDU (Chris Flatters)
Newsgroups: comp.windows.x
Subject: Re:  Can some one help me with Image package
Message-ID: <9010220118.AA25542@zia.aoc.nrao.edu>
Date: 22 Oct 90 01:18:51 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 19


Shyam Kotha writes:

> I want to acess pixel information of an image and manipulate them for writing 
> Image processing routines. I dont want to use XPutpixel etc as that slows
> down the whole thing, is there any way I can assign a arry containing the 
> pixel values to the data of the image.

You can access the image data directly through the data field of the
Ximage structure.  However, this can get pretty tricky since you
potentially have to keep track of the padding, depth, byte and bit order
and image format.  Not all of these are under your control.  You might
want to use direct access to the data in the most common circumstances
you might come across (eg. depth == 8 && format == ZPixmap) and
XGetPixel/XPutPixel for other circumstances so that your application
will at least run (albeit rather slowly) on displays that you didn't
anticipate.

			Chris Flatters