Fails to detect 32 bit depth

[posfan12]

I was having issues with an image generated by ImageMagick that turned out to instead be an issue with XnView.

See here: http://www.imagemagick.org/discourse-se ... 698#p84698

Input:

Output:


XnView does not report the output image as being 32 bits, but instead reports it as being 8 bits. The alpha channel is also ignored.

Thanks for any help you might provide!!

[XnTriq]

It's a know issue/limitation.

• PNG with transparency not showing
• PNG transparency problem
• 256-color png displayed in grayscale
• Incorrect display of a png image
• Alpha channel is ignored for grayscale PNG
• Wish: extract mask channel of PNG
• 8 bit png with alpha (8 bits) mask
• Partial Transparence in GFL_COLORS and GFL_GREY

[posfan12]

Thanks for the fast response.

So, the problem is that the image is a grayscale PNG? I mean, it has 8 bits of grayscale information and 8 bits of transparency information (for a total of 16bits)?

[XnTriq]

Yes

[MaxSt]

Yeah, we have been complaining about grayscale+alpha PNGs for years.

Even worse when it's APNG in grayscale+alpha... Then XnView cannot even recognize the file format as PNG.

[posfan12]

One of the people responding to the ImageMagick thread says that the input and output images use the same PNG specifications. However, if that is the case, why do they behave differently in XnView?

[MaxSt]

Both are valid PNG files, but there are 5 PNG image types:



First image is color type 6 (RGBA) and second image is color type 4 (GA).

XnView is known for having trouble displaying "type 4" files correctly.

[posfan12]

OK, thanks.