Re: Unassociated alpha channel

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Re: Unassociated alpha channel

Aaron Boxer
Note: Perhaps the problem is with my image viewer, which can't handle the opacity in the TIFF file ?

On Sat, May 27, 2017 at 11:01 AM, Aaron Boxer <[hidden email]> wrote:
Hi Folks,

I have a JPEG 2000 image with unassociated alpha channel.

When I decompress to TIFF using my JP2 library, I set the EXTRASAMPLE_UNASSALPHA flag for this channel. The resulting image is a black M with black background.

If I force the tag to EXTRASAMPLE_ASSOCALPHA, I get a white background.

I've attached the three files. The file with unassociated alpha looks odd to me. So, I wanted to verify that libtiff handles unassociated alpha channels without any knows problems.



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