mapview.hitTest doesn't return results if opacity is set

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10-02-2017 05:04 PM
JackFairfield
Occasional Contributor II

Why doesn't the mapview.hitTest method return any results?

Consider the simple example below:

If you modify this sample:

Access features with pointer events | ArcGIS API for JavaScript 4.5 

and add the opacity property to the feature layer like this

...

var layer = new FeatureLayer({
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Hurricanes/MapServer/1",
opacity: .4,
outFields: ["*"]
});

...

The hit test response will not contain and values in the results array.

Here is a jsbin link showing what I am talking about:

JS Bin - Collaborative JavaScript Debugging 

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14 Replies
RobertScheitlin__GISP
MVP Emeritus

Jack,

  that is definitely a bug because when you revert back to 4.4 it works.

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ThomasSolow
Occasional Contributor III

Yeah, looks like a bug to me.  Seems that anything less than 1.0 opacity doesn't work with hitTest in a MapView.

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JackFairfield
Occasional Contributor II

What can I expect for a bug fix like this?  Do I have to wait for 4.6 for a fix?

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ThomasSolow
Occasional Contributor III

I'm not sure.

You could use something like this for the time being:

// evt: ClickEvent, view: MapView
function getFeatures(evt, view){
  const pxRatio = view.extent.width / view.width,
        // number of pixels to check in
        pixelBuffer = 6,
        halfExtent = pxRatio * pixelBuffer,
        clickExtent = new Extent({
          xmin: evt.mapPoint.x - halfExtent,
          xmax: evt.mapPoint.x + halfExtent,
          ymin: evt.mapPoint.y - halfExtent,
          ymax: evt.mapPoint.y + halfExtent,
          spatialReference: view.extent.spatialReference
        });
              
  let queries = view.layerViews.map(lv => {
    let q = lv.layer.createQuery();
            
    q.geometry = clickExtent;
    q.geometryType = "esriGeometryEnvelope";
    q.outFields = null;
    q.where = null;
    return lv.queryFeatures(q);
  }).toArray();
          
  return Promise.all(queries).then(results => {
    return [].concat.apply([], results);
  });
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

example: JS Bin - Collaborative JavaScript Debugging 

This won't work as well as hitTest.  If you rely on this, it may be better to stick with 4.4 for the time being.

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JackFairfield
Occasional Contributor II

Thanks for the work around.  This doesn't seem to be fully working either unfortunately though.  Try clicking the biggest bubble in the example on the bottom right side.  It doesn't log any results.  Is there a place where I can track a bug like this and watch for fixes?

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ThomasSolow
Occasional Contributor III

Another workaround that seems to work is setting the layer's opacity to 1.0 but using a renderer to specify a symbol with opacity less than 1.0.  This doesn't seem to interfere with hitTest: https://codepen.io/solowt/pen/PJJLrw?editors=1000#0 

I reported the issue and I'll post here if I learn when it's going to be fixed.

JackFairfield
Occasional Contributor II

This does work as a temporary work around.  Thanks Thomas.

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ThomasSolow
Occasional Contributor III

Looks like this will be fixed in 4.6, sometime in early December.

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JackFairfield
Occasional Contributor II

Thanks for following up on this Thomas.

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