[mapserver-users] Rendering Challenges

[Brent Fraser]

Thomas,

   Interesting. I suspect all the polygons are digitized the same was as 
I think this is a requirement for shapefiles.  The result of using:

       STYLE
         OUTLINECOLOR 255 211 127
         OFFSET 1.5 -99
         WIDTH 3
       END

results in http://i54.tinypic.com/25a22k4.jpg  Close, but notice the 
"bleed" outside the polygon at the sharp corners.

Thanks!

Best Regards,
Brent Fraser


On 5/10/2011 1:38 AM, thomas bonfort wrote:
> Brent,
>
> those are interesting questions
>
> On Mon, May 9, 2011 at 21:51, Brent Fraser<bfraser at geoanalytic.com>  wrote:
>>   While testing v6, I can up with the following list of things I couldn't do
>> (see http://i56.tinypic.com/8vvprn.png for a graphic):
>>
>> 1. Render lines inside polygon boundary (with or without opacity)
> Along with Steve's buffer proposition, you can already more or less do
> that with OFFSET , except you don't have the notion of inside/outside,
> but left/right. If all your polygons are digitized in the same
> direction (i.e. clockwise or anticlockwise) this can be done with:
>
> STYLE
>    #FILL
> END
> STYLE
>     OUTLINECOLOR r g b
>     OFFSET 1.5 -99
>     WIDTH 3
>     OPACITY 50
> END
>
>
>
>> 2. Place polygon annotation on/inside boundary line
>> (http://trac.osgeo.org/mapserver/ticket/1592 point 8.)
> not possible in a single step, but by using the polygon layer a second
> time in a TYPE LINE layer for labelling should get you close.
>
>> 3. Rotate anno if required to fit inside a polygon
> would be a nice addition, ANGLE AUTO for polygon labels. We should
> probably give some way to define if the label should always follow the
> longest polygon diagonal, or if it should be first placed horizontally
> and fall back to automatic angling only if the horizontal one does not
> fit.
>
>> 4. Place polygon annotation outside polygon if anno doesn't fit inside
> The fine tuning on how to place the label text compared to the feature
> would require new mapfile keywords, but that would seem possible to
> implement. I'm not sure these kind of automatic adjustments would
> really enhance the rendered quality though.
>
>> 5. Place line anno above (or below) when using ANGLE FOLLOW
> This is something I would like to add to. There's a paper detailing
> the underlying algorithm here:
> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.24.6970
>
>> 6. Rotate vector symbols to follow lines (a font might work but is a pain to
>> create)
> how is this different than what we already have with a negative GAP?
> On a side note, vector symbols are currently rather ill-defined in
> mapserver and would need to be tightened up before being able to use
> them for precise symbol placement like here.
>
>> 7. User specified character spacing
> SIZE AUTO for labels in polygon layers would be a nice addition. We'd
> have to be able to define how the size of the font varies in
> accordance with the spacing that is applied between characters.
> Before going down that road, we shall have to implement the
> refactoring proposed in http://trac.osgeo.org/mapserver/ticket/3611 so
> as not to clutter the glyph rendering functions of each renderer.
>
>
>> 8. Erase lines (but not other objects) under annotation
> This seems rather involved. It would be difficult to keep the ordering
> of layers, as the modified feature could only be drawn during the
> labelcache phase, i.e. after all other features in the map.
>
>>   My goal was to use the published shp files
>> (http://ftp2.cits.rncan.gc.ca/pub/canvec/50k_shp/092/h/canvec_092h06_shp.zip)
>> without modification and see how close I could get to the published PDF
>> (http://ftp2.cits.rncan.gc.ca/pub/cantopo/50k_geopdf/092/h/cantopo_092h06_geopdf.zip).
>>
>>   Any suggested rendering techniques are appreciated.  I'll file tickets for
>> those problems deemed worthy.
> So, most of these enhancements seem possible, some were already on my
> laundry-list of rendering enhancements I'd like to tackle. Creating
> enhancement tickets for those features is a first step, and funding
> them is the second ;)
>
> regards,
>
> thomas
>
>> --
>> Best Regards,
>> Brent Fraser
>>
>>
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