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1996.11.14 17:05 "Single TIFF read/write", by Magdy Halim
1996.11.14 19:05 "Single TIFF read/write", by Frank Kim
1996.11.14 21:06 "Re: Single TIFF read/write", by Magdy Halim

1996.11.14 19:05 "Single TIFF read/write", by Frank Kim

Magdy Halim writes:
 > 
 > Hi Sam,
 > 
 > I was wondering if you know of a way to read and write to the same tiff
 > file. I tried the "r+" mode but i had to close and open the file every
 > time i change a scanline, besides it doesn't like compression (even when
 > the rowsperstrip field is 1).
 > 
 > The reason being that i have a 1.6 Gbyte image and opening a new one is
 > practically impossible.
 > 
 > All i wanna do is change some pixels inside the image.
 > 
 > Appreciate a quick reponse
 > 
 > Magdy


According to the HTML documentation (tiff-v3.4/html/libtiff.html#FIO):

      Note that unlike the stdio library TIFF image files may not be
opened for both reading and writing; there is no support for altering
the contents of a TIFF file.


I tried doing both a read and write in some programs.  Sometimes it
worked but other times I got seg faults.  I'd have to say it sounds like
a bad idea.

Frank Kim	NetCentric Corporation
		17 Monsignor O'Brien Highway, Cambridge, MA, 02141
		frankkim@server.net     (617)720-5200 x143
		http://cag-www.lcs.mit.edu/~frankkim/