Firefox can't print transparent PNG image from Mapserver

[Ei Fujioka]

Hi guys,

This may be a Firefox issue but want to know how you guys deal with this 
problem, if any, on your mapper application.

I got a weird problem that Firefox can't print a PNG image with
transparent background which is retrieved from Mapserver.
It's transparent on the browser, and so is it with [Print Preview].
But when I print this, the PNG image covers the legend and background
images (the transparent background turns to white).

To make things simple, I copied the PNG image in question along with
legend and some background map images into a quite simple HTML.

http://seamap.env.duke.edu:8888/dev/mapservice/googlemaps/test.html

Here, the combination of points and lines is the PNG with transparent
background. Should look OK on your browser.

Below is a screen shot of Firefox's [Print Preview].
http://seamap.env.duke.edu:8888/dev/cache/misc/firefox_cant_print_png.jpg

Still has transparent background, but when printed, it doesn't.


IE doesn't have this problem. It prints as seen on the browser.

Do you have any idea what's wrong?
Is it just a Firefox bug? Any workaround? Should use GIF?
# I thought Firefox provided great support for PNG...

<Excerpt from Mapfile>
IMAGETYPE png
OUTPUTFORMAT
   NAME png
   DRIVER "GD/PNG"
   MIMETYPE "image/png"
   IMAGEMODE PC256
   EXTENSION "png"
END

RESOLUTION 72
TRANSPARENT ON


<Mapserver version>
MapServer version 4.2.2 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP
OUTPUT=PDF SUPPORTS=PROJ SUPPORTS=FREETYPE SUPPORTS=WMS_SERVER
SUPPORTS=WMS_CLIENT SUPPORTS=WFS_SERVER SUPPORTS=WFS_CLIENT
INPUT=POSTGIS INPUT=OGR INPUT=GDAL INPUT=SHAPEFILE

<Environment>
ver 1.5.0.11 on Windows 2000
ver 1.5.0.11 on Windows Xp
A color printer and a B/W printer

Thanks,

Ei

-- 
======================
   Ei Fujioka
   Research Associate
   Duke University

   (919) 613-8021
   efujioka at duke.edu
======================