I used to work with libpng 1.2.43, mapserver 5.0 and chameleon as a tool to
display my maps. All was good, no problems.
I upgraded to libpng 1.6.2, mapserver 6.2 and GeoMoose to replace the
Now, for some reason all my png files are rendered with a bad quality,
although they look good in a normal viewer.
When I say bad quality, I mean they do not preserve the good quality, they
do not look sharpe and the color is not as in the original png file. Like
it renders an 8bit image instead of a 24bit, something like this.
Using commands like legend or shp2img (via Mapserver) i get the same
result, not good. I used to run a script to create maptiles whenever it
draws an icon I get a "libpng warning: iCCP: known incorrect sRGB profile"
error and the result is again, tiles with icons not rendered at a good
quality. The common link between them (I thought?) is probably libpng.
Can anyone help me out to try and find the issue? I am quite new to this
and any help is highly appreciated.
*Raiz Roland Robert*
Questions relating to libpng, as opposed to the PNG file format, need to be
asked on the png-mng-implement list, however in this case I suspect this is
an issue with the change to GeoMOOSE. It's quite possible that GeoMOOSE
does everything using just 256 colors, and it's quite possible that
shp2img changed in its handling of 24 bit rgb in the mapserver bump from
5.x to 6.x
I suggest you repost on png-mng-implement and include a sample mapfile, the
shp2img command that the new output. Ideally if you have it include the
original output, but in any case include the output when the image format
is set to JPEG.
Unfortunately I can't get shp2img to work - it just fails on the test.map
mapfile with "loadProjection(): Projection library error. Projection
support is not available. <br>", anyway test.map doesn't have any PNG files.