8 bit png with alpha (8 bits) mask

Bugs found in XnView Classic. Please report only one bug per topic!

Moderators: XnTriq, xnview

Post Reply
CheloXL
Posts: 6
Joined: Wed Jun 03, 2009 6:37 pm

8 bit png with alpha (8 bits) mask

Post by CheloXL » Mon Jun 08, 2009 1:19 pm

Hi,

It seems that XnView does not correctly supports 8 bit png (256 colors) with 8 bits mask? If I open the png in XnView, I see the image rendered without the mask and it is not possible to extract the mask, nor convert the file to any other format and retain the transparency.

The file was created with PNGOut and renders fine on any browser (that supports transparent png, of course).

It is possible for XnView to implement this feature? Maybe not writing, but at least reading...

Thanks in advance and regards,

User avatar
Clo
XnThusiast
Posts: 4441
Joined: Sun Oct 17, 2004 4:57 am
Location: Bordeaux, France
Contact:

Re: 8 bit png with alpha (8 bits) mask

Post by Clo » Mon Jun 08, 2009 1:53 pm

:arrow: CheloXL

:) Hello ! Welcome aboard !

• That works here : Image Menu >> Edit palette >> Tick the box
and click the cell of the BG colour you want as the transparency…

:mrgreen: Kind Regards,
Claude
Clo
Old user ON SELECTIVE STRIKE till further notice

CheloXL
Posts: 6
Joined: Wed Jun 03, 2009 6:37 pm

Re: 8 bit png with alpha (8 bits) mask

Post by CheloXL » Mon Jun 08, 2009 3:07 pm

That's not what I wanted. That creates an 8 bit png with 1 bit alpha mask - same as a GIF file. I'm talking about an 8 bit png with 8 bit alpha mask. It's like a 32 bits png (RGBA - 24.7millon colors + 256 grayscale mask), but instead of having 24bits for color, you have an indexed palette PLUS the alpha (256 levels of transparency).

Also, I would like XnView to display/convert the png correctly, not the ability to create this kind of png.

User avatar
xnview
Author of XnView
Posts: 31264
Joined: Mon Oct 13, 2003 7:31 am
Location: France
Contact:

Re: 8 bit png with alpha (8 bits) mask

Post by xnview » Tue Jun 09, 2009 7:28 am

Currently 8bits image + 8bits alpha is not supported
Pierre.

CheloXL
Posts: 6
Joined: Wed Jun 03, 2009 6:37 pm

Re: 8 bit png with alpha (8 bits) mask

Post by CheloXL » Tue Jun 09, 2009 2:28 pm

Hi Pierre,

Thanks. Do you have plans on supporting it?

Regards,

User avatar
xnview
Author of XnView
Posts: 31264
Joined: Mon Oct 13, 2003 7:31 am
Location: France
Contact:

Re: 8 bit png with alpha (8 bits) mask

Post by xnview » Wed Jun 10, 2009 7:51 am

CheloXL wrote: Thanks. Do you have plans on supporting it?
Yes, but as low level
Pierre.

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

Re: 8 bit png with alpha (8 bits) mask

Post by MaxSt » Thu Jun 11, 2009 8:11 am

Yeah, I noticed that too (see example below), but full PNG support is obviously (and sadly) not a high priority for XnView.
I like XnView, so it's sad to see it lagging behind even Internet Exprorer, with regard to PNG transparencies.

Image

Post Reply