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Most scaling algorithms remove alpha channel when resizing an image
Posted: Sat Jan 09, 2021 9:33 am
by damian101
With scaling methods Hermite, Gaussian, Bell, BSpline, Mitchell, Lanczos and Hanning the alpha channel gets removed when resizing an image.
Only Nearest Neighbor and Bilinear work as expected and preserve the alpha channel.
Re: Most scaling algorithms remove alpha channel when resizing an image
Posted: Thu Jan 14, 2021 8:43 am
by xnview
i can't reproduce, could you send me a sample image?
Re: Most scaling algorithms remove alpha channel when resizing an image
Posted: Sun Jun 13, 2021 1:30 pm
by damian101
xnview wrote: Thu Jan 14, 2021 8:43 am
i can't reproduce, could you send me a sample image?
Yes, I also could not reproduce this issue until I found the image I originally had the problem with. It's just 17x17 pixels in size, but it's not the size that causes this, since the issue can not be reproduced after reencoding the image with XnConvert.
Re: Most scaling algorithms remove alpha channel when resizing an image
Posted: Mon Jun 14, 2021 8:27 am
by xnview
I can't reproduce with the file, could you post a screenshot of resize dialog?
Re: Most scaling algorithms remove alpha channel when resizing an image
Posted: Fri Sep 10, 2021 12:21 am
by damian101
xnview wrote: Mon Jun 14, 2021 8:27 am
I can't reproduce with the file, could you post a screenshot of resize dialog?
Can't reproduce either now. I'm on Arch Linux, no idea why it did not work a few months back. Everything's working fine now.
