XnConvert [1.82+]: Alpha channel problems

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crazydaz
Posts: 11
Joined: Wed Nov 20, 2019 2:09 pm

XnConvert [1.82+]: Alpha channel problems

Post by crazydaz » Fri Jul 10, 2020 11:42 am

On 1.80 and earlier - "Change Color Depth 32bits Alpha 255" used to add pure white Alpha Channel.
On 1.82+ it does nothing.

If your image has alpha, and you simply convert it to 24bits it will look cutout.
In the past, it was possible to workaround it, by simply getting rid of Alpha Channel:

Converting it into full white 255, and then flattening it with 24 bits. Receiving a nice full image.

Now it's broken.

-
On 1.80:
Change Color Depth: 32 bits Alpha 255
Resize: 3k
ICC Convert
Canvas Resize: 3k x 3k , Alpha 255, Keep Ratio
Change Color Depth: 24 bits

Produces:
Image

On 1.85:
Same settings produce:
Image

crazydaz
Posts: 11
Joined: Wed Nov 20, 2019 2:09 pm

Re: XnConvert [1.82+]: Alpha channel problems

Post by crazydaz » Wed Jul 15, 2020 9:01 am

Change Color Depth is broken in 1.85.1.

But for my intended use, I managed to delete Alpha Channel by:

1. Create a full white image in any image editor and save it as GIF in XnConvert Mask directory:
On Mac: /Users/XXXXX/Desktop/XnConvert.app/Contents/Resources/AddOn/Masks/white.gif
2. In XnConvert Add action: "Add mask"
3. Navigate to the image you have created in the previous step:
e.g.: /Users/XXXXX/Desktop/XnConvert.app/Contents/Resources/AddOn/Masks/white.gif
2. Check "Use mask as Alpha"
4. Add "Change color depth"
5. Select "24 bits"

How do I invert the alpha channel of an image?

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xnview
Author of XnView
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Re: XnConvert [1.82+]: Alpha channel problems

Post by xnview » Mon Jul 20, 2020 1:20 pm

could you send me the original file?
Pierre.

crazydaz
Posts: 11
Joined: Wed Nov 20, 2019 2:09 pm

Re: XnConvert [1.82+]: Alpha channel problems

Post by crazydaz » Tue Jul 28, 2020 1:20 pm

xnview wrote:
Mon Jul 20, 2020 1:20 pm
could you send me the original file?
https://we.tl/t-ZrxYx0NkW0

I've included 3 files:
  • 1x Original
  • 1x generated with XnConvert 1.80:
    Change Color Depth: 32 bits Alpha 255
    Resize: 3k
    ICC Convert
    Canvas Resize: 3k x 3k , Alpha 255, Keep Ratio
    Change Color Depth: 24 bits
    Image
  • 1x generated with the same settings on XnConvert 1.85.1
    Change Color Depth: 32 bits Alpha 255
    Resize: 3k
    ICC Convert
    Canvas Resize: 3k x 3k , Alpha 255, Keep Ratio
    Change Color Depth: 24 bits
    Image

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xnview
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Posts: 33668
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Location: France
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Re: XnConvert [1.82+]: Alpha channel problems

Post by xnview » Wed Aug 12, 2020 3:41 pm

crazydaz wrote:
Tue Jul 28, 2020 1:20 pm
xnview wrote:
Mon Jul 20, 2020 1:20 pm
could you send me the original file?
https://we.tl/t-ZrxYx0NkW0
Sorry but the link has expired, could you post it again?
Pierre.

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