Label FOLLOW mode and POSITION CC/UC/LC

[Stephen Woodbridge]

Daniel Morissette wrote:
> Is it possible to control the relative position or offset of curved 
> labels (ANGLE FOLLOW) using POSITION CC/UC/LC?
> 
> In comment 39 of the curved labels bug 
> (http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1620#c39), Steve 
> suggested that we'd want that kind of control, but looking at the code 
> it seems to force position AUTO all the time.
> 
> Does anyone remember what was decided/done about this? Or is there 
> another bug about this?
> 
> Daniel

Daniel,

I describe the problem in comment 42. 
(http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=1620#c42) but I do 
not think it ever got tackled. The problem is that is it straight 
forward to do but non-trival and expensive. I probably means using geos 
buffer() command or implementing something similar to calculate the 
offset path then applying the label to the offset path.

It might be possible to walk along the segment and use vector algebra to 
  compute the offset, but the real problem as mentioned above is on the 
tight curves where the offset creates gaps in the segments on the 
outside of the curve and where segments are eliminated on the inside of 
the curve.

Anyway, I don't think Ben ever got back to looking at these options. It 
might be nice to add that to 5.0, if we can get Ben to take a look at 
adding it or if you are interested.

-Steve