Re: Basic question -- I am missing the "big picture" ...

Hi Jeff,

On Tuesday, April 30, 2002, at 05:26 PM, Jeff Mathis wrote:

> Well, it could very well be that I am missing the big picture, in that
> I'm really using the wrong tools to do what I need.
>
> Our application has several layers. Each layer has one or more data
> handlers. The data handlers, which all ultimately extend
> AbstractLocationHandler, are responsible for populating the
> OMGraphicList's.
>
> As the application runs, all the information in the various
> datahandlers change. I stumbled onto the doPrepare() method as a
> convenient way to do it all: regather the graphic objects, project,
> render and paint, all within its own SwingWorker thread. I created a
> manager class that kicks off the doPrepare() for each layer, then
> listens for LayerStatusEvent's to determine when all the threads have
> completed. When this manager's methods are called, they don't return
> until the painting is done, which was important for us.

Sounds like a solid approach to me.

>
> I was doing all the necessary calls myself. Using doPrepare()
> simplifies my life.

That's why it's there. :) I just meant that it wasn't a *Layer* method,
and that it's just in some layers.

> As a side note Don, I had told you awhile ago we would send you some
> screen shots and description of our product. We have been waiting for
> client sign off, which we now have. See the article below for a
> description of the application. We use OpenMap in the GUI to draw all
> the things going on with their North American operations.
>
> <http://globalarchive.ft.com/globalarchive/article.html?id=020430000298&query=
> tom+lloyd>http://globalarchive.ft.com/globalarchive/article.html?id=020430000298&
> query=tom+lloyd

Thanks for sending the link - was there a screen shot? Very interesting.

- Don

>
> Jeff
>
> At 01:19 PM 4/30/2002 -0400, Don Dietrick wrote:
>> I just wanted to mention a couple of things:
>>
>> The doPrepare() isn't a standard Layer method - it only exists on
>> certain layers. Ed, you may want to check out different OpenMap
>> layers to see how it is used, usually to kick off a SwingWorker to
>> tell a layer to re-gather graphics, project them and call repaint().
>> But, if your OMGraphics are pretty set, you can create a method (if
>> you don't have one) to just project your graphics and call repaint().
>>
>> How you manage your OMGraphics is completely up to you - you may want
>> to create them in the constructor, you may want to provide a method in
>> your layer so that other objects can create them. You may even want
>> an object in the MapHandler to hold on to them instead of your layer.
>> It all depends on how you want to organize and display your data. All
>> a layer is *really* responsible for, when you get right down to it,
>> is painting the OMGraphics in the right spot on the map relative to
>> other layers (depth). You just need to try to make sure that the only
>> thing that gets done in the paint() method of a layer is rendering.
>> Doing more makes the application feel slower.
>>
>> I don't think you want the MapHandler to be doing more than it already
>> does, which is enabling objects to find each other. If anything, I
>> would let a different object create your layer's OMGraphics, and then
>> use the MapHandler to let the layer find that object to get the
>> graphics (or vice versa). This requires that there some design
>> coordination between the layer and the object, but that's cool.
>>
>> - Don
>>
>> On Tuesday, April 30, 2002, at 12:04 PM, Jeff Mathis wrote:
>>
>>> Hi Ed,
>>>
>>> Glad to see you still hacking away.
>>>
>>> We do this all the time, as you might know. The key is when an object
>>> has been changed, you need to render the graphic and then repaint the
>>> layer.
>>>
>>> The doPrepare() method on Layer does most of this for you. What you
>>> have to realize here is that each layer is repainted in its own
>>> thread, but if you don't care then no extra handling is needed.
>>>
>>> Here is a snippet. This method is executed after the user is done
>>> dragging a map object to a new location:
>>>
>>> /**
>>> * Specified by the DrawingToolRequestor interface. This method
>>> is called after
>>> * the edit has been performed on a given location.
>>> * @param omg the OMGraphic object, which should be a MapEntity
>>> * @param oma the OMAction
>>> */
>>> public void drawingComplete(OMGraphic omg, OMAction oma) {
>>> Debug.message("entitylocationlayer","EntityLocationLayer:
>>> called drawingComplete");
>>> // reset the text label based on the circles coordinates
>>> MapEntity ent = (MapEntity)omg;
>>> OMGraphic g = ent.getLocationMarker();
>>> com.biosgroup.alac.model.general.Location newloc = null;
>>> if (g instanceof OMRect) {
>>> OMRect rect = (OMRect)g;
>>> ent.setLocation(rect.getNorthLat(), rect.getWestLon());
>>> newloc = new
>>> com.biosgroup.alac.model.general.Location((float)rect.getNorthLat(),
>>> (float)rect.getWestLon());
>>> } else if (g instanceof OMCircle) {
>>> OMCircle circ = (OMCircle)g;
>>> LatLonPoint l = circ.getLatLon();
>>> ent.setLocation(l.getLatitude(), l.getLongitude());
>>> newloc = new
>>> com.biosgroup.alac.model.general.Location((float)l.getLatitude(),
>>> (float)l.getLongitude());
>>> }
>>> ((Locatable)ent.getAppObject()).setLocation(newloc);
>>> g.setVisible(true);
>>> ApplicationState.fireApplicationChangeEvent(
>>> new ApplicationChangeEvent(this,
>>>
>>> ApplicationChangeEvent.LOCATION_EDITED));
>>> }
>>>
>>> then, when the ApplicationChangeEvent is received by my layer
>>> manager, it calls doPrepare() on the layer to repaint itself.
>>>
>>> At 09:40 PM 4/29/2002 -0600, Ed MacKerrow wrote:
>>>
>>>> Dear OpenMappers,
>>>>
>>>> I am still on the steep end of the OM learning curve and I think I
>>>> missing out on the "bigger picture".
>>>>
>>>> I have built a few layers that I have been able to display my
>>>> objects on, however, I did this by instantiating the objects, which
>>>> are displayed by association with a OMGraphic that has the same
>>>> (lat,lon)
>>>> as the App objs. The mistake that I believe I have done, is to
>>>> instantiate these objects and OMGraphics by calling a "buildObjs()"
>>>> method from inside the constructor for the layer. The layer
>>>> constructor is invoked from the properties file call (i.e. like in
>>>> the OpenMap app). Should I be instantiating these objects from a
>>>> mapHandler instead?
>>>>
>>>> The reason I am asking is that I don't know how to update the
>>>> positions of those objects on the layer, since I do not have an
>>>> instantiated object that represents my layer class. I guess my
>>>> basic question is:
>>>>
>>>> How do I update the position values of objects that are displayed on
>>>> a layer? ( are there any simple examples of updating the positions
>>>> of objects that are displayed on a layer out there?)
>>>>
>>>> Thanks for your help,
>>>>
>>>> ed
>>>
>>> Jeff Mathis
>>> Senior Scientist / Group Leader
>>> BiosGroup, Inc.
>>> 317 Paseo de Peralta
>>> Santa Fe, NM 87501
>>> direct: 505-992-6737
>>> fax: 505-988-2229
>>> jeff.mathis@biosgroup.com
>>> http://www.biosgroup.com
>>>
>>> --
>>> [To unsubscribe to this list send an email to "majdart@bbn.com"
>>> with the following text in the BODY of the message "unsubscribe
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>>>

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Don Dietrick, BBN Technologies, dietrick@bbn.com
10 Moulton Street, Cambridge, MA 02138
617-873-3031 [fax]-2794
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>
> Jeff Mathis
> Senior Scientist / Group Leader
> BiosGroup, Inc.
> 317 Paseo de Peralta
> Santa Fe, NM 87501
> direct: 505-992-6737
> fax: 505-988-2229
> jeff.mathis@biosgroup.com
> http://www.biosgroup.com
>

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