Example One: Named Style¶

A layer makes use of a WMS GeoResource, a NamedStyle from the Blackboard, this results in a WMSRenderer being chosen to draw onto the screen.

An editor makes use of the same layer, this time a WFS is used to access the real Feature data

Example Two: Named Style and SLD¶

Note that several renderers may draw from the same layer at once.

This time a custom SLD style is being used to draw the “selected” features

Streaming Renderer¶

uDig currently uses StreamingRenderer as a general purpose feature renderer.

There is an optimized ShapefileRenderer which is used to render shapefiles only. The shapefile renderer can only render data from shapefiles but it can do so at speeds from 20-500% faster than StreamingRenderer. Both feature renderers are fully SLD compliant.

GlassPane¶

The glasspane is a draw2D interface that you can use to draw directly onto the image drawn on the screen.

It does not use any of the rendering classes and does not listen to events.  If you want to update the screen and cause the GlassPane to be redraw you must call ViewportPane.repaint().

The glass pane is owned by the ViewportPane.  A ViewportPane can only have a single GlassPane.

The GlassPaneSite is an AbstractContext that contains the viewport model and helper functions to convert from screen to world and world to screen coordinates.  It is similar to the RenderContext associated with renderers.  Each GlassPane will have a single GlassPaneSite.

As shown in the following code snippet (from the ViewportPainter) the GlassPane is drawn after the background image (from the render manager) and before the draw commands.

public void paint( ViewportGraphics g, Image image, int minWidth, int minHeight ) {
    processCommands(g, true);
    clearPane(g, minWidth, minHeight);
    g.drawImage(image, 0, 0, minWidth, minHeight, 0, 0, minWidth, minHeight);

    //draw glass pane
    drawGlassPane(g);

    processCommands(g, false);
    runEditFeatureCommand(g);
}

Example of GlassPane¶

Two examples of using a glass pane can be found in the org.locationtech.udig.tutorials.tracking tutorial.

• SeagullGlassPaneOp - This adds an operation to the map.  When executed a glass pane is added to the map that draws seagulls. The map image is updated on a timer and the seagulls randomly moved based on another timer.
• SeagulTool - This is a modal tool that when activated adds a glasspane to the viewport pane and draws a set of seagulls on the screen. These seagulls will follow your mouse around the screen until the tool is deactivated.

Here are some subsets of code from these examples showing you how to add a new glass pane to the viewport pane and setup a timer to update the map at given intervals.

This code examples shows how to add a GlassPane to a given ViewportPane. In this example the draw() function is drawing the seagulls on the screen.

private void addFlockGlassPane(ViewportPane p, final Collection<Seagull> gulls){
       p.setGlass(new GlassPane(p){

           @Override
           public void draw( GC graphics ) {
               for( Iterator<Seagull> iterator = gulls.iterator(); iterator.hasNext(); ) {
                   Seagull bird = (Seagull) iterator.next();
                   bird.drawSeagull(graphics, this);
               }
           }});

   }

This example shows how to setup a Timer to update the map at fixed intervals.

//timer to update map
int refreshrate = 250;

//draws the map at given intervals
Timer mapupdatetimer = new Timer();
mapupdatetimer.scheduleAtFixedRate(new TimerTask(){
      @Override
      public void run() {
           viewer.repaint();
      }}, new Date(), refreshrate);

SeagullGlassPaneOp Demo¶

seagulls.swf

Rendering Events¶

The classes used in the rendering process are implemented using Eclipse Modelling Framework (so rather then list to events you have a notifier that issues every kind of event to various adaptors).

Here is a code example from Ugo Taddei:

// Print some state, for illustration's sake
System.out.println("Some Rendering States---------------");
System.out.println("IRenderer.STARTING " +  IRenderer.STARTING);
System.out.println("IRenderer.RENDERING " +  IRenderer.RENDERING);
System.out.println("IRenderer.DONE " +  IRenderer.DONE);

IMap map = mapViewer.getMap();
final IRenderManager rm = map.getRenderManager();

//only the RendererImpl has a visible RendererExecutor
final RenderManagerImpl rmi = (RenderManagerImpl) rm;

//add a listener to the model
rmi.getRenderExecutor().eAdapters().add(new AdapterImpl(){
   public void notifyChanged(Notification notification) {

    //on change, print the name (in RendererImpl only) and the state
       for (IRenderer rdr : rm.getRenderers()) {
           System.out.println( ((RendererImpl)rdr).getName() + " -> " +rdr.getState() );
       }
   }

});

You can also use something similar directly on a single renderer

((RendererImpl)rdr).eAdapters().add( theAdatper );