On Sun, May 8, 2011 at 2:07 AM, Jody Garnett <jody.garn...@gmail.com> wrote:
> Had another look at the proposal, setup as it is it will be harder than
> necessary to handle
> the switch of StreamingRenderer the Layer/MapContext API as the design of
> streaming
> renderer is style oriented, and the hierachy of Layer has getStyle() just as
> an afterthought.
> This is problematic in that it's the style that tells you if a layer is
> active, what parts of
> the data you're going to read and so on. It's the style that tells you if a
> raster layer
> is going to be painted as raster or as vector (one can apply a polygon
> symbolizer to
> rasters and just have the bounds be painted).
>
> I see. The intension was to only apply style to things that could use it.
>
> So I'd say that a first step to get things moving would to be a StyledLayer
> class
> acting as the base class of FeatureLayer, GridReaderLayer and CoverageLayer
> /**
> * Styled layer: data, in some form, with a style. The opposite of a
> DirectLayer,
> * that draws itself instead of declaring what data to be painted, and how
> */
> StyledLayer extends Layer {
> getStyle();
> setStyle(...)
> }
>
> Introducing StyledLayer should be perfectly fine.
>
> The second thing that is not clear in my mind is the relationship between
> DirectLayer
> paint method, the MapViewport in a MapContent, and GTRenderer various paint
> methods.
>
> Perhaps I should call it "DrawLayer" - let us look at the method(s):
> public abstract void draw(Graphics2D graphics, MapContent map, MapViewport
> viewport);
> paint(Graphics2D, Rectangle, AffineTransform)
> paint(Graphics2D, Rectangle, Envelope)
> paint(Graphics2D, Rectangle, Envelope, AffineTransform)
> paint(Graphics2D, Rectangle, ReferencedEnvelope)
> paint(Graphics2D, Rectangle, ReferencedEnvelope, AffineTransform)
>
> So the MapViewport contains the current area on screen... which is pretty
> much
> the same information provided to the paint methods, but in a different way.
>
> I see; so perhaps we could simplify the paint methods? MapViewport does
> contain a lot of the same information; but is missing the affine
> transformation (which I think was added after this work?).
Affine transform has been there for years. Adding them to the map viewport
is fine... btw, afaik Michael already added a rotation demo to the viewers,
how can you handle rotation without the affine transform?
> My preference would be to add affine transformation to MapViewport (it would
> allow for rotation I guess); and have a paint method that takes a
> MapViewport for consistency.
>
> And then the renderer should provide the direct layers with a viewport,
> but one derived from the paint method arguments... Isn't this confusing?
>
> It was my hope that this would be "documenting" and not confusing.
> MapViewport ties this information together; with javadocs and test cases;
> making it harder to screw up?
>From the point of view of who has to build one instead of using what's
already available it seems mostly busywork, but not much of it, not that
big of a problem (I hope, I'll only know when I actually try to factor
in direct layers).
Cheers
Andrea
--
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 962313
http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.youtube.com/user/GeoSolutionsIT
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf
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