Status: Read
Received: from [207.176.88.85] by phillip.cerious.com (NTMail 3.03.0017/7.aaxh) with ESMTP id pcrews for <pcrews@cerious.com>; Mon, 20 Mar 2000 20:49:17 -0500
Received: from localhost (daemon@localhost)
	by gate7.olympiakos.com (8.9.3/8.9.3) with SMTP id UAA09390;
	Mon, 20 Mar 2000 20:19:07 -0500
Received: by gate7.olympiakos.com (bulk_mailer v1.9); Mon, 20 Mar 2000 20:11:18 -0500
Received: (from majordom@localhost)
	by gate7.olympiakos.com (8.9.3/8.9.3) id UAA08844
	for tiff-outgoing; Mon, 20 Mar 2000 20:11:07 -0500
X-Authentication-Warning: gate7.olympiakos.com: majordom set sender to owner-tiff@olympiakos.com using -f
Received: from smtp6.mindspring.com (smtp6.mindspring.com [207.69.200.110])
	by gate7.olympiakos.com (8.9.3/8.9.3) with ESMTP id UAA08841
	for <tiff@olympiakos.com>; Mon, 20 Mar 2000 20:11:04 -0500
Received: from pskellic (user-33qtp9l.dialup.mindspring.com [199.174.229.53])
	by smtp6.mindspring.com (8.9.3/8.8.5) with SMTP id UAA23537
	for <tiff@olympiakos.com>; Mon, 20 Mar 2000 20:10:55 -0500 (EST)
Received: by localhost with Microsoft MAPI; Mon, 20 Mar 2000 18:23:17 -0700
Message-ID: <01BF9299.5CA91660.pskellic@ix.netcom.com>
From: Scott&Patty <pskellic@ix.netcom.com>
Reply-To: "pskellic@ix.netcom.com" <pskellic@ix.netcom.com>
To: "'tiff@olympiakos.com'" <tiff@olympiakos.com>
Subject: raster scaling
Date: Mon, 20 Mar 2000 18:23:07 -0700
X-Mailer: Microsoft Internet E-mail/MAPI - 8.0.0.4211
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: owner-tiff@olympiakos.com

I'll try again...

---------

Hi all,

I realize that this post is a bit off topic, but I'm grasping at straws at
this point.

The gist of my question is, "How do I _quickly_ scale down a monochrome
image?"  In particular, I want to preserve "on" pixels in large (~10k x ~10k
pixels) images.  I have seen a number of products that do this very well.
"Zooming out" on a large image is practically instantaneous and the pixels
are dithered to gray-scale resulting in very fine lines.  While Wang Imaging
(for Windows) is slow at load-time and memory heavy compared to some I've
seen, it does do display of monochrome images like I'm interested in.

I've checked the Graphics Gems series, Foley and van Dam, and a number of
the standard journals all to no avail.  Am I missing something obvious?

I should probably state that I have of course tried optimizing the brute
force method of checking every pixel that lies within the newly scaled
pixel.  As hard as I try to optimize, I am still _significantly_ slower than
what I've seen (not to mention that I'm not even trying to generate gray
level pixels based on the density of "on" pixels).

Thanks for any help (and please forgive my ignorance <g>).

Scott
