Re: [udig-devel] Custom Renderer

[Jody Garnett <jgarnett@xxxxxxxxxxxxxxx>]

Edwards, Wendy A ERDC-CERL-IL Contractor wrote:

> Hi, we're working on some code to get UDIG to open and render DXF files.  It
> seems likely that we'll need a custom renderer, though it should be possible
> to extend BasicFeatureRenderer.  How should this be added to UDIG?  From what
> I understand, we should create a new plugin to do this, rather than modify
> existing code.  Is there any documentation explaining this?  I noticed that
> the section on renderers didn't seem to be up yet.
Hi Wendy,

Can I ask for a bit more detail on what a DXF file is? Depending on the 
data type you may not need to
make a renderer at all (simply teach udig how to load your information).

The existing renderer makes use of "Style Layer Descriptor" allowing you 
to do all sorts of complicated things. The only reason to make a custom 
renderer is for speed (if you know more about your data you may be able 
to go faster), or for special things like CAD file formats that include 
per feature color information.

So the range of options varies from ....

Hooking into the geotools feature type system:
- create a GeoTools DataStore (for feature data)
- create two glue classes (IService and IGeoResource) to allow uDig to 
hold onto your files in a project

Or creating a renderer that works right from your file format:
- create a IRenderer (and associated Factory and Metrics class)
- the glue classes will still need to be written

Cheers,
Jody