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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/


AWARE [SYSTEMS]		Imaging expertise for the Delphi developer
		TIFF and LibTiff Mailing List Archive
	LibTiff Mailing List TIFF and LibTiff Mailing List Archive November 1996 Previous Thread Next Thread Previous by Thread Next by Thread Previous by Date Next by Date Contact The TIFF Mailing List Homepage This list is run by Frank Warmerdam Archive maintained by AWare Systems	Thread 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/

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