Return-Path: <tiff-bounces@lists.maptools.org>
Received: from inas021.isp.belgacom.be (localhost [127.0.0.1])
        by inav017.isp.belgacom.be (8.12.11.20060308/8.12.11/Skynet-IN-AV-3.00) with ESMTP id k3B8cqcV000573
        for <joris.at.lebbeke@skynet.be>; Tue, 11 Apr 2006 10:38:53 +0200
        (envelope-from <tiff-bounces@lists.maptools.org>)
Received: from inmx005.isp.belgacom.be (inmx005.isp.belgacom.be [195.238.5.148])
        by inas021.isp.belgacom.be (8.12.11.20060308/8.12.11/Skynet-IN-AS-2.03) with ESMTP id k3B8ckPk008880
        for <joris.at.lebbeke@skynet.be>; Tue, 11 Apr 2006 10:38:49 +0200
        (envelope-from <tiff-bounces@lists.maptools.org>)
Received: from duke.maptools.org (r153.dmsolutions.ca [209.217.116.153] (may be forged))
        by inmx005.isp.belgacom.be (8.12.11.20060308/8.12.11/Skynet-IN-2.32) with ESMTP id k3B8ce82030449
        for <joris.at.lebbeke@skynet.be>; Tue, 11 Apr 2006 10:38:40 +0200
        (envelope-from <tiff-bounces@lists.maptools.org>)
Received: from duke.maptools.org (duke.maptools.org [127.0.0.1])
	by duke.maptools.org (8.12.11/8.12.10) with ESMTP id k3B8XqGW013662;
	Tue, 11 Apr 2006 04:34:33 -0400
Received: from outmx020.isp.belgacom.be (outmx020.isp.belgacom.be
	[195.238.4.201])
	by duke.maptools.org (8.12.11/8.12.10) with ESMTP id k3B8XnEc013659
	for <tiff@lists.maptools.org>; Tue, 11 Apr 2006 04:33:49 -0400
Received: from outmx020.isp.belgacom.be (localhost [127.0.0.1])
	by outmx020.isp.belgacom.be (8.12.11.20060308/8.12.11/Skynet-OUT-2.22)
	with ESMTP id k3B8XiY6006668
	for <tiff@lists.maptools.org>; Tue, 11 Apr 2006 10:33:45 +0200
	(envelope-from <joris.at.lebbeke@skynet.be>)
Received: from dfgrrxsknr4e (167.164-246-81.adsl-dyn.isp.belgacom.be
	[81.246.164.167])
	by outmx020.isp.belgacom.be (8.12.11.20060308/8.12.11/Skynet-OUT-2.22)
	with SMTP id k3B8XgPe006619; Tue, 11 Apr 2006 10:33:42 +0200
	(envelope-from <joris.at.lebbeke@skynet.be>)
Message-ID: <000c01c65d42$a5a163c0$a7a4f651@dfgrrxsknr4e>
From: "Joris" <joris.at.lebbeke@skynet.be>
To: "Gerben Vos" <Gerben@zylab.com>, "tiff" <tiff@lists.maptools.org>
References: <FC840EC0BF7BFA45A0F94548AF36920DABF1FF@zynlms01.ZyLAB.WAN>
Subject: Re: [Tiff] LibTiff Suggestion,
	Need help to support  application supplied JPEGTables.
Date: Tue, 11 Apr 2006 10:33:34 +0200
MIME-Version: 1.0
Content-Type: text/plain;
	charset="gb2312"
Content-Transfer-Encoding: 7bit
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2800.1506
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1506
Cc: 
X-BeenThere: tiff@lists.maptools.org
X-Mailman-Version: 2.1.4
Precedence: list
List-Id: TIFF and libtiff discussion <tiff.lists.maptools.org>
List-Unsubscribe: <http://lists.maptools.org/mailman/listinfo/tiff>,
	<mailto:tiff-request@lists.maptools.org?subject=unsubscribe>
List-Archive: <http://lists.maptools.org/mailman/private/tiff>
List-Post: <mailto:tiff@lists.maptools.org>
List-Help: <mailto:tiff-request@lists.maptools.org?subject=help>
List-Subscribe: <http://lists.maptools.org/mailman/listinfo/tiff>,
	<mailto:tiff-request@lists.maptools.org?subject=subscribe>
Sender: tiff-bounces@lists.maptools.org
Errors-To: tiff-bounces@lists.maptools.org
X-UIDL: 000000000023ceae.0000157d
X-MSP-STORE: Tue, 11 Apr 2006 10:39:01 +0200
Status:   

Gerben,

Gerben Vos wrote:
> I agree that it would be nice to be able to specify the quantisation
> tables using a pseudo tag.

I've not had time yet to dive into tif_jpeg.c, but I will soon.

Meanwhile, why are you refering to a pseudo tag? Would it not suit these
needs, if the actual JpegTables tag can be set, and when next LibJpeg is
used to compress, in this case, the application supplied tables that are
set in this tag are used?

> However, maybe for your application at this moment it would be easier
> to do the JPEG compression yourself, and then use the raw strip/tile
> writing functions?

You can do that, because the tables inside the strip/tile are supposed
to overwrite the tables inside the JpegTables tag, if there are tables
in both.

But
a) are you sure LibTiff reads back like it is supposed to, in this case?
b) that would be a (very small, perhaps negligable) waste of storage
space.

Or am I misunderstanding?


Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be/
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html

_______________________________________________
Tiff mailing list: Tiff@lists.maptools.org
http://lists.maptools.org/mailman/listinfo/tiff
http://www.remotesensing.org/libtiff/
