Fails to detect 32 bit depth

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posfan12
Posts: 5
Joined: Sun Mar 25, 2012 12:52 am

Fails to detect 32 bit depth

Post by posfan12 » Thu May 10, 2012 2:44 pm

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:
Image
Output:
Image

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!!
Last edited by posfan12 on Sun May 20, 2012 3:07 am, edited 1 time in total.


posfan12
Posts: 5
Joined: Sun Mar 25, 2012 12:52 am

Re: Fails to detect 32 bit depth

Post by posfan12 » Thu May 10, 2012 8:47 pm

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)?

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XnTriq
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Re: Fails to detect 32 bit depth

Post by XnTriq » Thu May 10, 2012 9:15 pm

Yes :|

Image

MaxSt
Posts: 133
Joined: Fri Apr 10, 2009 9:55 pm

Re: Fails to detect 32 bit depth

Post by MaxSt » Fri May 11, 2012 4:08 am

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
Posts: 5
Joined: Sun Mar 25, 2012 12:52 am

Re: Fails to detect 32 bit depth

Post by posfan12 » Sun May 20, 2012 3:09 am

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
Posts: 133
Joined: Fri Apr 10, 2009 9:55 pm

Re: Fails to detect 32 bit depth

Post by MaxSt » Mon May 21, 2012 4:32 am

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

Image

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
Posts: 5
Joined: Sun Mar 25, 2012 12:52 am

Re: Fails to detect 32 bit depth

Post by posfan12 » Tue May 22, 2012 9:55 pm

OK, thanks.

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