From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@quanstro.net>
Date: Sat, 12 Dec 2009 15:00:49 -0500
To: 9fans@9fans.net
Message-ID: <94e0e78e118b2061dfbc997c199f14f6@ladd.quanstro.net>
In-Reply-To: <<20091212144519.GA2904@zoidberg.hsd1.mi.comcast.net>>
References: <<20091212144519.GA2904@zoidberg.hsd1.mi.comcast.net>>
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Subject: Re: [9fans] radar for plan 9, and two draw funnies.
Topicbox-Message-UUID: af0ce1f2-ead5-11e9-9d60-3106f5b1d025

> On Fri, Dec 11, 2009 at 08:51:21PM -0500, erik quanstrom wrote:
> > 1.  for some reason the hw.gif (interstates) are
> > in cyan not red.  drawing the radar first and the
> > hw second yields inverse radar colors.
> In what order are you layering the images? According to [1] they are layered
> left to right as on the toggle bar.
>
> [1]http://www.srh.noaa.gov/jetstream/doppler/ridge_download.htm

i think that's beside the point here.  the colors get inverted regardless
of the order of composition.  try compose -t topo.jpg radar.gif hw.gif.
(this is the same order as on the site).  in this case the radar image has
the wrong colors.

it looks like an α² problem, but i don't think it is.  if you use an r8g8b8
base image, the color effects still happen.  m8a8 yields black.  i didn't
know that was legal, yet:
; gif -9 radar.gif|dd -count 1 -bs 50>[2=]; echo
       m8a8           0           0         600   ;

it's especially odd to try these two:
	; compose -c m8 -t topo.jpg radar.gif hw.gif
	; compose -c m8 -t topo.jpg hw.gif radar.gif

- erik