[Tilesathome] Default layer transparent

[Frederik Ramm]

Hi,

> Some reasons for updating:
> sea is now rendered as sea, not as land as it was before.
> lowzoom uses 67/69 byte blank images
> maplint layer transparent, default not

I was unhappy about the hard-codedness of this. After all, the maplint 
layer could be called anything, it's just a token really, so it is not 
nice to check for "maplint" in tilesGen.pl. I modified this to

       if ($Config{"Layer.$layer.Transparent"})
       {
         $SubImage->transparent($SubImage->colorAllocate(248,248,248));
       }
       else
       {
         $SubImage->transparent(-1);
       }

However after making this change it occurred to me that we still have a 
nasty dependency here because this depends on "f8f8f8" being used as the 
background colour, right?

Is there a reason why we need to handle transparency in this stage - if 
we put a proper "fill-opacity" style in the osmarender rule file, does 
that not work?

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'