[VPM] Correct List?

[Peter Scott]

I don't have any experience with PNG formats.  Anyone on the list got any 
help for Timothy?

At 06:20 PM 6/27/2003 -0700, Timothy wrote:
>Now a Perl question. I am attempting to read PNG files with Perl. Most
>of it is fairly basic. However I am having a heck of a time figuring
>out how the IDAT chunk works. I've read in the appropriate chunk from the
>file as $strData.
>
>   $strData = uncompress($strData);                     # <-- from Zlib
>   @PNGIDAT = unpack("C" x length($strData), $strData);
>
>So far so good. Now this is a 3x3 image true color, non-interlaced and
>a bit depth of 8. The image is simply plain white. However when I print
>the RGB values I don't get all 255s I get this:
>
>    1 255 255 255   0   0   0   0   0   0
>  255   0   0   0   0   0   0   2   0   0
>    0   0   0   0   2   0   0   0   0   0
>
>I guess I'm not unpacking them correctly? The rest other chunks I had
>no problems with. Any insight? TIA:)

--
Peter Scott
peter at psdt.com
http://www.perldebugged.com