[OpenLayers-Dev] Re: Adding Segment Length to Path

[Xavier Mamano (jorix)]

Hi Yus,

Interesting...

You will need to assign value to the `vlayer` in callbacks `create` and
`modify` as:
```
var vlayer = this.handler.layer;
```
that's it!

Xavier


Yus wrote
> 
> Hi.
> 
> Ran into a small problem when change to OpenLayers 2.11 with showing the
> length of each segment on the measuring line.
> 
> Previously after placing points A --> B, B --> C. The length of segment A
> to B would show up between those points, likewise with B to C and after
> ending the line the total would be displayed.
> 
> My script worked fine with OpenLayers 2.10, but after changing to
> OpenLayers 2.11 as soon as I end the line only the segment values
> disappear from the vector layer.
> 
> I understand the problem, but am having trouble working out the logic...
> 
> Below is the script I am using:
> line: new OpenLayers.Control.Measure(OpenLayers.Handler.Path, {
>     persist: true,
>     handlerOptions: {
>         layerOptions: {
>             renderers: renderer,
>             styleMap: styleMap
>         }
>     },
>     textNodes: null,
>     callbacks:{
>         create:
>         function(){
>             this.textNodes = [];
>             vlayer.destroyFeatures(vlayer.features); *<-- Believe the
> problem is here*
>             mouseMovements = 0;
>         },
>         modify:
>         function(point, line){
>             if(mouseMovements++ < 5){
>                 return;
>             }
>             var len = line.geometry.components.length;
>             var from = line.geometry.components[len -2];
>             var to = line.geometry.components[len -1];
>             var ls = new OpenLayers.Geometry.LineString([from, to]);
>             var dist = this.getBestLength(ls);
>             if(!dist[0]){
>                 return;
>             }
>             var total = this.getBestLength(line.geometry);
>             var label = dist[0].toFixed(3) + " " + dist[1];
>             var textNode = this.textNodes[len -2] || null;
>             if(textNode && !textNode.layer){
>                 this.textNodes.pop();
>                 textNode = null;
>             }
>             if(!textNode){
>                 var c = ls.getCentroid();
>                 textNode = new OpenLayers.Feature.Vector(
>                 new OpenLayers.Geometry.Point(c.x, c.y), {}, {
>                     label: "",
>                     fontColor: "#800517",
>                     fontSize: "12px",
>                     fontFamily: "Tahoma",
>                     fontWeight: "bold",
>                     labelAlign: "cm"
>                 });
>                 this.textNodes.push(textNode);
>                 vlayer.addFeatures([textNode]);
>             }
>             textNode.geometry.x = (from.x + to.x) / 2;
>             textNode.geometry.y = (from.y + to.y) / 2;
>             textNode.style.label = label;
>             textNode.layer.drawFeature(textNode);
>             this.events.triggerEvent("measuredynamic", {
>                 measure: dist[0],
>                 total: total[0],
>                 units: dist[1],
>                 order: 1,
>                 geometry: ls
>             });
>         }
>     }
> }),
> 
> Any advice is very appreciated. Thanks in advance
> 


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