| Date: | 2009/01/26 |
|---|---|
| Authors: | Thomas Bonfort, Stephen Lime |
| Contact: | Thomas.Bonfort at camptocamp.com , Steve.Lime at DNR.State.MN.US |
| Status: | Passed and Implemented |
| Version: | MapServer 5.4 |
| Id: | $Id: ms-rfc-49.txt 8455 2009-01-25 17:29:53Z tbonfort $ |
This RFC regroups a few minor additions or changes to the MapServer rendering or mapfile syntax.
These changes are/were all in RFC45, but were extracted to keep things moving on as some of the stuff in RFC45 lacks funding in the near future.
AGG can deal with fractional widths and sizes but styleObj’s define those properties as int’s. Shouldn’t be a big deal since both GD and AGG don’t use those values directly, rather they use scaled values with are cast or rounded to an int if necessary.
These keywords can reduce mapfile size and maintainance, by avoiding creating multiple layers or classes.
It is currently impossible to draw a outlined line with a scale-dependant width. We propose to add the OUTLINWIDTH keyword to the STYLE block, that indicates the width in pixels that should be rendered around the main line color.
The implementation of this lies in mapdraw.c. When a line’s style block has an outlinewidth, the underlying shape is actually drawn twice: once with it’s width adapted to account for the outlinewidth, and once normally. The current caching mechanism for lines is preserved.
example usage:
LAYER
TYPE LINE
SIZEUNITS meters
CLASS
STYLE
COLOR 255 0 0
OUTLINECOLOR 0 0 0
OUTLINEWIDTH 1
WIDTH 25 #this is in meters (ground units)
MINWIDTH 1 #minimal width (in pixels) for far zoomed maps
MAXWIDTH 20 #maximal width (in pixels) for close zoomed maps
END
END
END
whatever the map extent or scale, this line layer would always be rendered by a red line with a one pixel black outline.
Note
This feature has not yet been implemented
so that a default can be defined for all classes (sort of like templates). A class label would take precedent.
The documentation for the keywords will be aded to the main mapfile syntax docs.
Getters and Setters for the keywords will be added for mapscript availability
None Expected
the LABELMETHOD proposal is withdrawn
fractional values also for pattern,gap, offset: a good candidate for 6.0 (when pattern and gap would be moved to the styleObj?)
there was concensus for adding parametered scaling, usefull for thematic mapping (eg size proportional to a feature attribute)
by allowing simple expressions, eg SIZE ( 18 + [poptotal] * (( 43-18)/(5000-30000)) )
or by adding pseudoitems at the layer level:
PSEUDOITEM
'mySize' (mrange([itemname], mininput, maxinput, minoutput,
maxoutput))
'myText (commify(round([itemname], 2)) + ' ac')
END
LABELITEM 'myText'
CLASS
STYLE
COLOR 255 0 0
SIZE [mySize]
END
LABEL
...
END
END
this enhancement will be addressed in a specific rfc.
+1 : SteveW, UmbertoN, TamasS, SteveL, DanielM (,AlanB)