[mapserver-users] Rendering with a single transparent colours in MapServer 6

[Brad Posthumus]

We need to create 8-bit PNG images in MS 6.0 that have one single colour
(white) designated as transparent with all other colours as 100% opaque.
Using the GD driver with PC256 works well with vectors but not with fonts
(see
http://osgeo-org.1803224.n2.nabble.com/Font-rendering-in-MapServer-6-0-td6555935.html
). Using the AGG driver with quantization creates nice images but with
semi-transparent colours, a feature Internet Explorer 6 tends to butcher. Is
there another option?

As an example, right now we're using this as our output format to create the
image that follows:

  OUTPUTFORMAT
    NAME png8
    DRIVER "AGG/PNG8"
    MIMETYPE "image/png; mode=8bit"
    IMAGEMODE RGBA
    EXTENSION "png"
    FORMATOPTION "INTERLACE=off"
    FORMATOPTION "QUANTIZE_FORCE=on"
    FORMATOPTION "QUANTIZE_COLORS=256"
    TRANSPARENT ON
  END
http://osgeo-org.1803224.n2.nabble.com/file/n6769109/comparingAGGQuantization.png 

What we need is the following image (created using GD and PC256):
http://osgeo-org.1803224.n2.nabble.com/file/n6769109/comparingGDPc256.png 

Is this possible in MS 6.0?

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