Re: [png-mng-implement] IE6/IE7 cannot display PNG24 file which contains onlye ONE color

[John B. <jb...@ac...>]

>- IE6/IE7 cannot display PNG24 file which contains only ONE color[1] 

It has no problem displaying such images, however the test case has an invalid background (bKGd) chunk - it references palette entry '1', which does not exist.  (BTW pngcheck does not detect this.)

>My question is: Is there any (other, good) workaround for this issue?

Don't store invalid bKGd chunks ;-)  In this case the decoder could determine beforehand that the background is never used, but I suspect most decoders are just stuffing 'black' into the unspecified palette entries, so the result is potentially undefined.  For example:

>[vuhung@aoclife GraphicsMagick]$ gm identify -verbose -verbose 
>PNG24.only.one.color.cannot.be.displayed.under.IE6.IE7.png
>...
>  Colors: 1
>    0: (180,200,240)      #B4C8F0
>...
>  Background Color: black

I wonder where that came from...

John Bowler <jb...@ac...>