[Mapserver-dev] Label rendering Mapserver 3.7 - problems

[Havard Tveite]

I have experienced some problems with label rendering for
cached labels.
I tried to inform the user-list some weeks ago (Thu, 23 Jan
2003 14:42:47 +0100), but I have so far not seen any replies.

The problem is that the label background and the lables are
not scaled correctly. If I include the label background
I can see that the label background is not the same size as
the label, and the there is also a misalignment on the left
end of the label.
I have tried to look at the source code, but there is a lot
of things going on inside msDrawLabelCacheGD (msGetLabelSize,
....., billboardGD, msDrawTextGD), gdImageStringFT, ....
I have not found out if the problem is with GD, Freetype or
Mapserver.
I guess there are others that have more experience with the
code out there.
Does anyone have an idea of what is going on?
Am I the only one having this problem?
Should I file this as a bug in Bugzilla?


My configuration is:

Mapserver 3.7, nightly 23. january.
(Solaris 2.5.1)
MapServer version 3.7 (development) OUTPUT=PNG OUTPUT=JPEG
  OUTPUT=WBMP SUPPORTS=PROJ SUPPORTS=TTF SUPPORTS=WMS_SERVER
  SUPPORTS=WMS_CLIENT SUPPORTS=GD2_RGB INPUT=EPPL7 INPUT=SDE
  INPUT=POSTGIS INPUT=GDAL INPUT=SHAPEFILE

GDAL 1.1.8
GD 2.0.11
PostGIS 0.7.3
Freetype 2.1.2


You can see the output of one of my tests here (try to zooom in and out):
<URL: http://gis.nlh.no:8080/cgi-bin/mapserv_3.7?map=/home/ikf/ikfht/mapserv/o-kart/labeltest-37.map >

Everything seems work OK with bitmap fonts.

The mapfile producing this output:

*******************************************************
MAP
  NAME labeltest
  IMAGETYPE png   # png24 gives the same results
  SIZE 400 400
  EXTENT 0 0 1000 1000
  UNITS meters
  FONTSET /home/www/lib/fonts/font.list
  WEB
    IMAGEPATH "/home/ikf/ikfht/pub_html/mapserver/tmp/"
    IMAGEURL "/~ikfht/mapserver/tmp/"
    TEMPLATE /home/ikf/ikfht/pub_html/mapserver/o-kart/labeltest.html
  END #web

  SYMBOL
    NAME "circle"
    TYPE ellipse
    FILLED true
    POINTS 1 1 END
  END

  LAYER
    NAME fonttest
    TYPE POINT
    STATUS DEFAULT
    LABELMINSCALE 1000    # This seems to have no effect on the label scaling
    LABELMAXSCALE 100000  # This seems to have no effect on the label scaling
    MINSCALE 500          # This seems to have no effect on the label scaling
    SYMBOLSCALE 10000     # This has effect on label scaling
    MAXSCALE 200000       # This seems to have no effect on the label scaling
    FEATURE
      POINTS 100 500 END
      TEXT "test y"
    END
    CLASS
      COLOR 255 0 0
      SYMBOL "circle"
      SIZE 10
      LABEL
        COLOR 0 0 0
        BACKGROUNDCOLOR 200 200 100
        POSITION UR
        TYPE truetype
        FONT arial
        MINSIZE 10  # this has no effect on the label background scaling
        SIZE 20
        MAXSIZE 30 # this has no effect on the label background scaling
      END
    END # CLASS
  END # LAYER

END
*******************************************************


-- 
Håvard Tveite                      Phone:  +47 64948857
Department of Mapping Sciences     Fax:    +47 64948856
Agricultural University of Norway
POBox 5034, N-1432 Ås, NORWAY    http://www.nlh.no/ikf/