How to not auto centralize viewer selectionIndicator poistion for an entity with label, billboard and polyline?

omar · October 18, 2019, 1:56am

The entity selector uses the entity’s bounding sphere to figure out where it should go. This is where the bounding sphere for the entities is computed:

github.com

CesiumGS/cesium/blob/6361718743dba781d01bdf12118fa0458d9f3755/Source/DataSources/DataSourceDisplay.js#L304


 *
 * @param {Entity} entity The entity whose bounding sphere to compute.
 * @param {Boolean} allowPartial If true, pending bounding spheres are ignored and an answer will be returned from the currently available data.
 *                               If false, the the function will halt and return pending if any of the bounding spheres are pending.
 * @param {BoundingSphere} result The bounding sphere onto which to store the result.
 * @returns {BoundingSphereState} BoundingSphereState.DONE if the result contains the bounding sphere,
 *                       BoundingSphereState.PENDING if the result is still being computed, or
 *                       BoundingSphereState.FAILED if the entity has no visualization in the current scene.
 * @private
 */
DataSourceDisplay.prototype.getBoundingSphere = function(entity, allowPartial, result) {
    //>>includeStart('debug', pragmas.debug);
    Check.defined('entity', entity);
    Check.typeOf.bool('allowPartial', allowPartial);
    Check.defined('result', result);
    //>>includeEnd('debug');


    if (!this._ready) {
        return BoundingSphereState.PENDING;
    }

And this is where the viewer sets the indicator to be that computed bounding sphere center:

github.com

CesiumGS/cesium/blob/6361718743dba781d01bdf12118fa0458d9f3755/Source/Widgets/Viewer/Viewer.js#L1581-L1593


if (showSelection && selectedEntity.isShowing && selectedEntity.isAvailable(time)) {
    var state = this._dataSourceDisplay.getBoundingSphere(selectedEntity, true, boundingSphereScratch);
    if (state !== BoundingSphereState.FAILED) {
        position = boundingSphereScratch.center;
    } else if (defined(selectedEntity.position)) {
        position = selectedEntity.position.getValue(time, position);
    }
    enableCamera = defined(position);
}


var selectionIndicatorViewModel = defined(this._selectionIndicator) ? this._selectionIndicator.viewModel : undefined;
if (defined(selectionIndicatorViewModel)) {
    selectionIndicatorViewModel.position = Cartesian3.clone(position, selectionIndicatorViewModel.position);

You could override that behavior in the source code, or expose a function in the API to expose a way to customize/override this (and it would be great to make a pull request contribution back into CesiumJS)!

You also just disable the selection indicator and listen for the selectedEntityChanged event on the viewer to detect when a selectedEntity has change and create your own indicator, which might be the easiest approach to customizing it in your application.

Let me know if this helps!

Topic		Replies	Views
Entities - selection indicator and clustering CesiumJS	4	1392	October 10, 2018
Position of the selection rectangle when using polyline CesiumJS	1	465	August 14, 2019
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How to not auto centralize viewer selectionIndicator poistion for an entity with label, billboard and polyline?

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