[mapserver-dev] plugin renderer support status update

Havard Tveite havard.tveite at umb.no
Tue Dec 30 09:21:20 EST 2008

thomas bonfort wrote:
> This could be the time to break some backwards compatibility with
> respect to type vector symbols:
>  * switch their rotation direction: their angle is currently treated
> clockwise, all other symbols are anticlockwise (or the other way
> around, I don't remember)

It would be very nice if the ANGLE options proposed in RFC45
could be implemented at the same time.
This would improve Mapserver's symbol flexibility, and it
would also make it much easier to handle the change of
default rotation direction.
In RFC45, the following modes of operation for ANGLE has
been proposed:
DEFAULT (counter-clockwise, reference direction to the right/east)
CLOCKWISE (reference direction to the right/east)
COMPASS (reference direction to the north, clockwise rotation)

> * I'd also like to have the vector symbols be centered on their (0,0)
> point, which would allow preciser placement. thoughts... ?

I agree that it is very important to improve the support for
precise symbol placement.  ORIGIN/CENTER has been proposed
in RFC45.
For vector symbols it seems sensible to change the default
symbol placement to the centre of the symbols bounding box
to the (0,0) point.  However, I think we should strive for
consistency between the different symbol types (pixmap,
vector, truetype, ellipse).  And for pixmaps, I would guess
that the centre of the bounding box would be the natural
choice - and the same goes for ellipses, I guess.
One could perhaps define (0,0) as the centre of a pixmap /
ellipse symbol's bounding box?

I think it is important that all the symbol issues are seen
together, so that we end up with something that is consistent
and logical.
I would therefore suggest that RFC45 is updated according to
the recent input on the lists.

Håvard Tveite

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