[OpenLayers-Users] Measure Control - get distance on mouse move - part 2

[Andreas Hocevar]

Josh Rosenthal wrote:
> Thanks a lot for the solution using callbacks.  I was wondering if you 
> could suggest how that might be adapted to give the measurements on a 
> draw feature.  It's much easier than what I was previously doing for 
> measure and drawFeature (passing a customized modifyFeature function in 
> the options, where the new function was the same as the original, but 
> also had the requisite getLength statements - functional, but it seems 
> like this should be far more version dependent than the callback solution).
> 
> When I try to use callbacks-modify on a drawFeature (as below), my 
> modify callback doesn't seem to get used (the console.log(this) never 
> fires).  I assume this is because measureControls didn't already use a 
> modify callback, whereas drawFeature does, and as such drawFeature 
> overrides any modify callback I might try to pass in?  Is there any way 
> to append to the normal modify callback?  Am I missing something obvious?

The best way to achieve this would be to listen for the sketchmodified 
event of the DrawFeature control. this is what actually gets triggered 
in the modify callback of the handler that is configured with DrawFeature.

Regards,
Andreas.

> 
> Thanks! 
> 
> Josh
> 
> broken: uses callbacks - modify: 
>  selectDrawCircle = new OpenLayers.Control.DrawFeature(selectLayerPoly,
>                         OpenLayers.Handler.RegularPolygon,{
>                             displayClass:"olControlSelectDrawCircle",
>                            
>  element:document.getElementById('SelectControl_Distance'),
>                            
>  unitElement:document.getElementById('SelectControl_mapUnit'),
>                             callbacks:{
>                                 modify: function (point,feature) {
>                     console.log(this);
>                                   this.element.value=this.radius.toFixed(2);
>                                  
>  this.unitElement.innerHTML=this.map.getUnits();                         
>        
>                              }
>                             },
>                             handlerOptions:{
>                                 sides:40
>                                   }
>                                 });
>                             
> functional: uses slightly customized modifyGeometry function passed in 
> as an option
>                  selectDrawCircle = new 
> OpenLayers.Control.DrawFeature(selectLayerPoly,
>                         OpenLayers.Handler.RegularPolygon,{
>                             displayClass:"olControlSelectDrawCircle",
>                             handlerOptions:{
>                                 sides:40,
>                                
>  element:document.getElementById('SelectControl_Distance'),
>                                
>  unitElement:document.getElementById('SelectControl_mapUnit'),
>                                 modifyGeometry: function() {
>                                     var angle, dx, dy, point;
>                                     var ring = 
> this.feature.geometry.components[0];
>                                     // if the number of sides ever 
> changes, create a new geometry
>                                     if(ring.components.length != 
> (this.sides + 1)) {
>                                         this.createGeometry();
>                                         ring = 
> this.feature.geometry.components[0];
>                                     }
>                                     for(var i=0; i<this.sides; ++i) {
>                                         point = ring.components[i];
>                                         angle = this.angle + (i * 2 * 
> Math.PI / this.sides);
>                                         point.x = this.origin.x + 
> (this.radius * Math.cos(angle));
>                                         point.y = this.origin.y + 
> (this.radius * Math.sin(angle));
>                                         point.clearBounds();
>                                     }
>                                     // note, only val b/c this is an 
> input field.
>                                   this.element.value=this.radius.toFixed(2);
>                                  
>  this.unitElement.innerHTML=this.map.getUnits();
>                                 }
>                          }});
> 
> 
> On Wed, Apr 22, 2009 at 8:22 AM, Andreas Hocevar <ahocevar at opengeo.org 
> <mailto:ahocevar at opengeo.org>> wrote:
> 
>     Hi,
> 
>     the solution (if you're using trunk or 2.8) is quite simple. The snippet
>     below replaces the definition of measureControls in the measure example
>     (starting around L65)
> 
>                measureControls = {
>                    line: new OpenLayers.Control.Measure(
>                        OpenLayers.Handler.Path, {
>                            callbacks: {
>                                modify: function(point, feature) {
>                                  
>      measureControls.line.measurePartial(point,
>                                            feature.geometry);
>                                }
>                            },
>                            persist: true,
>                            handlerOptions: {
>                                layerOptions: {styleMap: styleMap}
>                            }
>                        }
>                    ),
>                    polygon: new OpenLayers.Control.Measure(
>                        OpenLayers.Handler.Polygon, {
>                            callbacks: {
>                                modify: function(point, feature) {
> 
>     measureControls.polygon.measurePartial(point,
>                                            feature.geometry);
>                                }
>                            },
>                            persist: true,
>                            handlerOptions: {
>                                layerOptions: {styleMap: styleMap}
>                            }
>                        }
>                    )
>                };
> 
>     As you can see, the trick is to add a modify callback to the handler,
>     calling the control's measurePartial method.
> 
>     Regards,
>     Andreas.
> 
>     pribram pribram wrote:
>      > Hi,
>      > Is there anything new about measuring + getting distance on
>     mousemove?
>      >
>     http://n2.nabble.com/Measure-Control---get-distance-on-mouse-move-td2503580.html
>      > If there is a solution, please publish it.
>      >
>      > Thanks,
>      > Pribram
>      > _______________________________________________
>      > Users mailing list
>      > Users at openlayers.org <mailto:Users at openlayers.org>
>      > http://openlayers.org/mailman/listinfo/users
>      >
> 
> 
>     --
>     Andreas Hocevar
>     OpenGeo - http://opengeo.org/
>     Expert service straight from the developers.
> 
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> 
> 


-- 
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.