Re: png image scrambled

On Fri, 23 Aug 2019, Roland Winkler wrote:

> The attached png image is not displayed correctly, and I am trying
> to find out the cause of this.
>
> I am not a png expert.  I ran into this because GNU Emacs (that uses
> libpng) does not display this image as expected, unlike other
> applications including eog and imagemagick.

Are you saying that eog and imagemagick appear to display the image 
correctly?  I looked at it with GraphicsMagick and it does not look 
"scrambled", although the image is very tiny so it is difficult to 
look at without magifying it.

> Then I built the test program rpng.  It displays this image in the
> same scrambled way as emacs.  Is this due to a corrupted image (that
> other applications handle more graciously) or is this a bug in libpng?

The probability that this is due to a bug in libpng is exceedingly low 
since it likely has a billion users.

It may be that there is a problem with how the test program was 
compiled and linked.

Bob
-- 
Bob Friesenhahn
[email protected], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
Public Key,     http://www.simplesystems.org/users/bfriesen/public-key.txt