ALPHACOLOR_ENABLED code in mapfile.c

[Daniel Morissette]

We've been reminded in bug 2052 
(http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=2052) that there is 
some unused code in mapfile.c and a few other files dating from 2003 to 
add ALPHA to the ColorObj. This code is all inside #ifdef 
ALPHACOLOR_ENABLED but there is no documentation for this or any way to 
use this code without manually adding the flag to the makefiles (i.e. no 
configure options, etc.).

Steve's suggestion in the bug, which I agree with is:

> I haven't had any plans (or heard a good reason) to use alpha channel values in 
> colors. Rather I would support a style-level or label-level opacity value that 
> would serve that function and impact all colors associated with an object. 
> Doing so would mitigate configuration confusion, would not require a change to 
> the colorObj (and all supporting code), and would keep configuration in the 
> mapfile straight forward.
> 
> Unless other complelling reasons exist (and they might) I would just as soon 
> remove all references to ALPHACOLOR_ENABLED...


I'm sending this email to find out if anyone sees a need to maintain, 
complete and document this code to handle ALPHA in the ColorObj. If not 
then we'll remove the code and add style-level or label-level opacity to 
the TODO list as suggested by Steve.

Daniel

P.S. Please reply to mapserver-dev and not via the bug report. This 
question is off-topic for the bug which was just about a compile error 
and turned into a longer debate about the usefulness of this code.
-- 
Daniel Morissette
http://www.mapgears.com/