In order to convert images of some alpha channels correctly.

[abobong]

test1.png

test2.png

1.

Test1.png is a transparent image of two colors. (Transparent white)
Test2.png is a black alpha channel image of [one color].

Please tell me how to convert it to webp, .bmp, .tiff etc. without losing transparency information of these images.

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2.
My aim is to convert 8-bit transparent index images etc. to 32-bit format compatible with alpha channel. (That is, .gif conversion is not included)

But the result of this simple conversion work was a cool two color finish of white and black. (Like a dot image)

test1bad.png

test2bad2(24bit).png

test3.png

3.
*Other
Test3.png is an alpha layer with 256 colors of grayscale.
Although the white background is originally a transparent part, it seems that it can not be completely read. Let's expect from the future xnview series.*

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4.
After all, in order to preserve the [transparency] information accurately, as an example, I thought of a method to convert the image to a 32-bit alpha channel,
I do not understand how to do it properly.
By the way, please refer to this article for the conversion method.
http://newsgroup.xnview.com/viewtopic.p ... bp#p130494

test1good(32bit).png

test2good(32bit).png

test3(32bit).png

The last 3 images are the images I am aiming for.
Since it already converted to 32 bits, it seems that it will not collapse even if it converts it to another format.

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Postscript: This article was scheduled to be posted on [General Support].
I tried to submit it in order,
I decided to post to [Suggestions].
Sorry

[abobong]

Summary of requests.

* Increase the writing precision of the alpha channel *


When converting the transparency index image (8 bits) to full color (24 bits or more), please improve so that you can output accurate alpha channel with default settings.

I think that this kind of flexibility is necessary for handling images of the next generation.

[XnTriq]

I support this request.

The following attachment is the result of converting test1.png to 32-bit color depth with XnView Classic:

p143016.bmp

Transparency is preserved.