Re: [udig-devel] ApplicationGIS drawMap example

[<Stephen.Egan@xxxxxxxx>]

Hi Jody & Jesse,

 

I’ve made a bit of progress here since yesterday after you put me on the right track.  I adjusted the BasicRenderListener inner class in BasicFeatureRenderer (eventually found it – Eclipse’s “Open Type” couldn’t pick it up).  Commenting out the code in the featureRenderer() method that periodically called setState() seems to get me half of the way there.  Now the layer is displayed all in one go rather than updating on screen.

 

However, the map is still cleared before the rendering takes place, whereas I would rather the previous image is maintained until the updated one is ready, providing a smoother animation.  It’s worth noting that this behaviour only occurs when there is a very large number of features to render (>12,000 is when it becomes an issue with what I am doing).  I’m fiddling around with the RedrawJob in RenderExecutorComposite, but so far no luck.  I will vandalise RenderJob next to get the clearBounds() method to do nothing and see if that gets me closer.

 

No doubt there is a less idiotic approach that can be taken, which I’ll be only to delighted to hear about.

 

Thanks again for your help,

 

Stephen.

 

From: Jody Garnett [mailto:jody.garnett@xxxxxxxxx]
Sent: Thursday, 20 January 2011 3:25 PM
To: Jody Andrew Garnett; Jesse Eichar
Cc: User-friendly Desktop Internet GIS; Egan, Stephen (CES, Highett)
Subject: Re: ApplicationGIS drawMap example

 

Okay in discussion on IRC the actual request turned out a bit different.

 

The idea is to delay a layer refresh; until the entire image is ready. The idea is to update a style; and not watch the screen draw the new features in. Since the rendering system is listening to the renderer turn over and issue events; perhaps we could configure the renderer to only issue an event when it is "done" ?

 

Jesse you are a bit more familiar with the rendering system at this level; could we, place something on the style blackboard and then modify the BasicFeatureRenderer to issue less events in this case?

 

Jody

 

On 19/01/2011, at 2:21 PM, Jody Garnett wrote:

Here is a cut&paste of calling AppplicationGIS.drawMap (it comes from the box preview code used in printing):

 

    BufferedImage preview;

    State current;

    public void createPreview( Graphics2D graphics, final IProgressMonitor monitor ) {

              Dimension size = getBox().getSize();

 

        try {

            if (map != null) {

                preview = new BufferedImage(size.width, size.height, BufferedImage.TYPE_INT_ARGB);

                Graphics2D g = preview.createGraphics();

                try {

                    ApplicationGIS.drawMap(new DrawMapParameter(g, new java.awt.Dimension(

                            size.width, size.height), this.map, monitor));

                } finally {

                    g.dispose();

                }

                current = new State(map.getViewportModel(), getBox().getSize());

                graphics.drawImage(preview, 0, 0, size.width, size.height, 0, 0,

                        preview.getWidth(), preview.getHeight(), null);

            }

        } catch (Exception e) {

            PrintingModelPlugin.log("", e); //$NON-NLS-1$

            String message = "Error rendering Map:  " + e.getMessage(); //$NON-NLS-1$

            drawErrorMessage(graphics, message);

        }

        setDirty(false);

    }

 

You could do something similar to get an image; for use in a View.

 

To make a single threaded renderer we could use this code as an example; MapEditor uses the "widget" MapViewer to get the job done; perhaps we can teach it to be single threaded using something similar to ApplicationGIS.drawMap.

 

Out of curiosity why are you interested in a single threaded renderer?

 

Jody