Re: [udig-devel] DropAction Coordinate from DropEvent won't convert corr

[ukpete <pete@xxxxxxxxx>]

It works!!!!  Thanks so much for the info and superfast reply Jesse.

Pete


Jesse Eichar wrote:
> 
> Hi,
> 
> There are 2 possible issues here:
> 
> 1.  I think that the drop coordinates are with respect to the  
> Display,  Not the Map.  So first thing that has to be done is it has  
> to be converted to the map coordinates.  Fortunately the Viewport is  
> a Composite so it is easy.  Here's a snippet for you:
> 
> 
>      @Override
>      public void perform( IProgressMonitor monitor ) {
>          final String string=getData().toString();
> 
>          // Since I declared my target to be a ViewportPane then I  
> know that is what the
>          // destination is going to be.
>          MapEditor editor=(MapEditor) getDestination();
> 
>          // In order to know where to draw the string we have to  
> calculate where the
>          // drop event has taken place with respect to the ViewportPane.
>          // The Event returns the location but it is w.r.t the Display.
>          // All SWT widgets have helper methods to determine this so:
>          Control control=editor.getComposite();
>          final Point drawLocation = control.toControl(getEvent().x,  
> getEvent().y);
> 
>          // By Adding a custom draw command we can draw on the  
> viewport model...
>          editor.getMap().sendCommandASync(new AbstractDrawCommand(){
> 
>              public Rectangle getValidArea() {
>                  // I'm being lazy and returning null so that this  
> will be re-drawn every time the
>                  // Viewport is updated.
>                  return null;
>              }
> 
>              public void run( IProgressMonitor monitor ) throws  
> Exception {
>                  // draw the string
>                  graphics.drawString(string, drawLocation.x,  
> drawLocation.y,
>                          ViewportGraphics.ALIGN_LEFT,  
> ViewportGraphics.ALIGN_BOTTOM);
>              }
> 
>          });
> 
>      }
> 
> For this example to work the target of the operation must be a  
> MapEditor.
> 
> 2.
> PixelToWorld Converts from the Screen to the Map (the CRS provided by  
> the ViewportModel).  You have to convert the coordinate from the map  
> CRS to the layer CRS.  I made a code example that you can look at here:
> 
> <http://svn.geotools.org/udig/branches/1.1.x/udig/tutorials/ 
> net.refractions.udig.code.examples/src/net/refractions/udig/code/ 
> examples/PickTool.java>
> 
> 
> Hope this helps,
> 
> Jesse
> 
> 
> 
> On 16-Jan-07, at 7:51 AM, ukpete wrote:
> 
>>
>> Hello all,
>>
>> I have a noob kind of problem,  pixelToWorld doesnt seem to be  
>> converting my
>> screen coordinates correctly to the specific layer I am dropping  
>> on.  The
>> coordinates are "off" sometimes by a significant percentage.  Here  
>> is an
>> example of the code I first attempted:
>>
>> clickedLocation =
>> ApplicationGIS.createContext(ApplicationGIS.getActiveMap 
>> ()).pixelToWorld(this.getEvent().x,
>> this.getEvent().y);
>>
>> I've also used this:
>>
>> clickedLocation =
>> currentMap.getViewportModel().pixelToWorld(this.getEvent().x,
>> this.getEvent().y);
>>
>> I suspect its something to do with the CRS of the layer I am  
>> drawing on - is
>> there a snippet of code out there that will resolve this regardless  
>> of the
>> layer I am dropping onto?  This code is embedded inside a  
>> DropAction object
>> added through the usual extension mechanism, thus the event I am  
>> using is a
>> DropEvent - if that makes any difference...
>>
>> Kind Regards,
>>
>> Pete Cornwell
>> -- 
>> View this message in context: http://www.nabble.com/DropAction- 
>> Coordinate-from-DropEvent-won%27t-convert-correctly- 
>> tf3021691.html#a8392444
>> Sent from the udig-devel mailing list archive at Nabble.com.
>>
>> _______________________________________________
>> User-friendly Desktop Internet GIS (uDig)
>> http://udig.refractions.net
>> http://lists.refractions.net/mailman/listinfo/udig-devel
> 
> 
> _______________________________________________
> User-friendly Desktop Internet GIS (uDig)
> http://udig.refractions.net
> http://lists.refractions.net/mailman/listinfo/udig-devel
> 
> 

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