[mapserver-users] 24 bit PNG transparent symbols

[Ben Brehmer]

Hi List,

I've been trying to get 24 bit PNG symbols to be transparent.

I've tried both GD and AGG output. I've tried --with-experimental-png. 
I've tried editing the symbol in photoshop to be transparent. Basically 
fooled around with all the different output format options. I've tried 
both RGB and RGBA png images.

8 bit PNG symbols work just fine. But the 24 bit symbols always have a 
white and non-transparent background (see attached image).

Is there any other mapfile configurations I can try before I convert all 
of my 24 bit images to 8 bit?

Or maybe this is a known bug?

Thanks,

Ben


------------------------------------------

I'm using:

MapServer version 5.2.0 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP 
OUTPUT=SVG SUPPORTS=PROJ SUPPORTS=AGG SUPPORTS=FREETYPE SUPPORTS=ICONV 
SUPPORTS=WMS_SERVER SUPPORTS=WMS_CLIENT SUPPORTS=WFS_CLIENT 
SUPPORTS=FASTCGI INPUT=EPPL7 INPUT=POSTGIS INPUT=OGR INPUT=GDAL 
INPUT=SHAPEFILE

(also tried Mapserver 5.2 with SUPPORTS=RGBA_PNG )


The mapfile:

MAP
..
    IMAGETYPE "aggpng24"

  OUTPUTFORMAT
    TRANSPARENT ON
    NAME 'aggpng24'
    DRIVER "AGG/PNG"
    MIMETYPE "image/png mode=24bit"
    EXTENSION "png"
    IMAGEMODE RGBA #also tried RGB for rgb png images
...
    #NAME "gdpng24"
    #DRIVER "GD/PNG"
    #MIMETYPE "image/png"
    #EXTENSION "png"
    #IMAGEMODE RGB #RGBA

END

LAYER
    CLASS
       STYLE
          SYMBOL "../../htdocs/images/markers/blue_star_32.png"
       END
    END
...
.
END
   
--------------------------------------  

gdalinfo output:

Driver: PNG/Portable Network Graphics
Size is 32, 32
Coordinate System is `'
Metadata:
  Software=Adobe ImageReady
Corner Coordinates:
Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,   32.0)
Upper Right (   32.0,    0.0)
Lower Right (   32.0,   32.0)
Center      (   16.0,   16.0)
Band 1 Block=32x1 Type=Byte, ColorInterp=Red
Band 2 Block=32x1 Type=Byte, ColorInterp=Green
Band 3 Block=32x1 Type=Byte, ColorInterp=Blue
Band 4 Block=32x1 Type=Byte, ColorInterp=Alpha



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