Hi Gilles Did you try TRANSPARENCY alpha (on LAYER level).
Mit freundlichem Gruss / Best Regards Flavio Hendry ---------------------------------------------------------------- TYDAC Web-Site: http://www.tydac.ch TYDAC MapServer: http://www.mapserver.ch ---------------------------------------------------------------- ############ Mit freundlichen Gruessen / Kind Regards ############ mailto:[EMAIL PROTECTED] ############ TYDAC AG - http://www.tydac.ch #### #### Geographic Information Solutions #### #### Luternauweg 12 -- CH-3006 Bern ############ Tel +41 (0)31 368 0180 - Fax +41 (0)31 368 1860 ---------------------------------------------------------------- -----Original Message----- From: Gilles Bassière <[EMAIL PROTECTED]> To: [email protected] Date: Thu, 30 Aug 2007 16:44:41 +0200 Subject: [UMN_MAPSERVER-USERS] AGG, paletted image and transparency (Mapserver 5.0 beta 5) > Hi List, > > I run Mapserver 5.0 beta5 as a WMS server and have some troubles with > background transparency :( > > In a first attempt, I just replaced my GD OUTPUTFORMAT definition by: > > OUTPUTFORMAT > NAME "png" > DRIVER "AGG/PNG" > MIMETYPE "image/png" > IMAGEMODE "rgba" > EXTENSION "png" > FORMATOPTION "transparent=on" > # TileCache can't use meta-tiling on interlaced PNG files... > FORMATOPTION "interlace=off" > END > > Changed my config to have my OpenLayers pointing directly at > Mapserver > 5.0, launch my browser and... Wow, it looks great !!! > > Then, I tried some optimization and I added to my OUTPUTFORMAT > element > (as seen in "AGG rendering specifics" howto) : > FORMATOPTION "quantize_force=on" > FORMATOPTION "quantize_dither=off" > FORMATOPTION "quantize_colors=256" > > Well, the line work is still beautiful but I now have 2 problems : > 1) I lost background transparency. My tiles appear with a white > background, I tried to change IMAGECOLOR from 255 255 255 to -1 -1 > -1, > also to remove this element but it doesn't change anything. > 2) Fonts and symbols looks very crappy, they are mixed black and > white > where they should be filled with black with a white outline. > > On a random tile, the image size fall from 102KB down to 25KB. Such > ratio is not representative at all since it's not an average and it's > only about vector data but still, quantize option seems very > interesting > and I don't want to give up because of transparency problems. > > Trying to solve the first problem, I found a workaround for the > second. > When I set the TRANSPARENT parameter of the WMS request to 'false' > (or > any value different of 'true'), then fonts and symbols are displayed > normally. It could have been ok if TRANSPARENT was not an optional > parameter... The map should looks good in the default case. > > Does someone could give more explanation about the quantize option, > especially regarding transparency management ? > > If possible, a broader answer about the FORMATOPTION element would > help > a lot. Indeed, it seems like most optimizations are possible through > output format tuning. Unfortunately, I have not been able to find any > reference document on this... > > Regards, > > -- > Gilles Bassiere > MAKINA CORPUS > 30 rue des Jeuneurs > FR-75011 PARIS > http://www.makina-corpus.com
