About PNG output. Uncompressed PNG.

[Bob Basques]

Ed McNierney wrote:

>Bob -
>
>What is it you're trying to accomplish?  All PNG images are compressed,
>in that they all use deflate compression on the data stream.  The data
>stream is filtered first to optimize it for compression; while you can
>control the choice of filter, I do not believe there is any control over
>the compression.
>
>The compression is completely lossless, so there is absolutely no
>degradation of the image (as opposed to JPEG, for example).  Saying you
>want "PNG with 0 compression" is sort of like saying "I would like
>EXACTLY the same image in this file, just puff up the file to make it
>bigger".
>
>If you are simply trying to get the best quality PNG image, you've
>already got it.  If you're looking for something else, let us know.
>Thanks!
>  
>
Ed,

I'm experimenting with dissecting the PNG image with Javascript.  The 
idea is to try and pull the Image Pixel data (color values) into a 
Javascript Array in the Client, a Browser in this case.

I'm still doing some of the research on it at the moment.  I'm just 
checking on the notion of setting the Compression level on the server is 
all.

bobb


>	- Ed
>
>Ed McNierney
>President and Chief Mapmaker
>TopoZone.com / Maps a la carte, Inc.
>73 Princeton Street, Suite 305
>North Chelmsford, MA  01863
>ed at topozone.com
>(978) 251-4242 =20
>
>-----Original Message-----
>From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
>Behalf Of Bob Basques
>Sent: Tuesday, January 10, 2006 4:40 PM
>To: MAPSERVER-USERS at LISTS.UMN.EDU
>Subject: [UMN_MAPSERVER-USERS] About PNG output. Uncompressed PNG.
>
>All,
>
>I don't really know what I'm asking here, but here goes.
>
>What Compression value does MapServer use for outputting PNG images? =20
>Can this be adjusted.  I'm interested in outputting PNG's with 0 (zero)=20
>compression.   Is there a setting somewhere for this?
>
>bobb
>
>  
>