2008.05.26 17:11 "Re: [Tiff] Unitialized Variable Caused a Problem in TIFFCP", by Gene Amtower

On Sat, 2008-05-24 at 10:34 -0500, Bob Friesenhahn wrote:

I don't see any samples-per-pixel tag in the above output so I expect that the reported libtiff defect is due to using the wrong interface to obtain the tag. The TIFFGetFieldDefaulted() function should be used rather than TIFFGetField(). If TIFFGetField() is used, then it is necessary to verify that the return value is 1 before deciding to use the result.

This seems to be quite rare, and perhaps violates the TIFF specification.

I was of the same opinion, as I suspect the software that is generating the problem images could be over 10 years old. As such, I hate to say this is a code problem and add code to the release to correct a data problem, but I'll defer to those who work with this package regularly. For my usage, I've defaulted the subject variable to "1" to avoid the error message with my images.

3.9.0beta contains important bug fixes. The focus has been on libtiff 4.0, which is a feature release (BigTIFF support).

I copied my watermarking additions to the 4.0.0beta2 code package, then recompiled and tested. I noticed that the 'bias' routine had some minor restructuring for error conditions, and I updated my 'watermark' routine accordingly. For my usage, it's working great.

I know my code doesn't manage all potential input file formats - i.e. more work is required to allow watermarking for colored images. Hence, it may not be "ready for prime time". I played with different methods to watermark the images, but my final method of applying the watermark image is through a bit-level 'or' of the two image 'values' because my image and watermark files are b/w. Each input value contained a pixel per bit, so I had to work at a bit-level rather than a value-level to get the desired output. Others may have watermarking needs that I have not included, so this function may work incorrectly for their images.

Should I submit any code to the team? Being new to this process, how would I do that? (file attachment? CVS access? other?) I know it's not the most important thing on the libtiff list, but I want to "feed" my effort back to the team to help bring down the MS mother-ship. I didn't see anyone submitting new functionality in my review of the last 6 months of list postings, so I'm a bit in the dark on how to proceed.

Thanks for the help,

Gene