Re: [Geotools-gt2-users] Multiple datasets with the same Renderer

[Martin D. <mar...@no...>]

Richard Milton a =E9crit :
> I was wondering whether anyone has come across a demo for 2.1/2.2 that=20
> can display a 50MB shapefile (say postcode areas)

No demo were done as far as I know. J2D renderer is currently quite bad r=
egarding memory usage with=20
big shapefile. However, it doesn't need to be bad since it was designed w=
ith some kind of streaming=20
in mind. Technically, what need to be done is a subclass of org.geotools.=
renderer.array.PointArray=20
specialized for fetching ShapeFile data straight from the disk. We have n=
ot yet had the time to go=20
to this point, but all the hooks are in place. This work is planned for t=
he ongoing GO-1 renderer,=20
which is a J2D renderer rewrite. Different method names for OGC complianc=
e (Renderer --> Canvas,=20
RenderedLayer --> Graphic), but quite similar design (with many shortcomm=
ing fixed in the process).


> [...snip...]. Adding a new=20
> RenderedLayer to the existing Renderer duplicates the geometry

Actually it is a little bit more sophesticated. I don't know for JTS geom=
etry objects. But in the=20
case of org.geotools.renderer.geom.Geometry objects used by J2D renderer,=
 Geometry objects are=20
cloned, but not the underlying coordinate arrays. So cloning geometries a=
re not supposed to be very=20
expensive (if it is, then it is a bug).

I'm afraid that this mail is not of great help in near term. Just wanted =
to inform what is planned...

	Martin.