I added callout to my map, it has to show some metainformation, not only coordinates (I used setDetail method)!
I did not find methods for scaling it.
We have not parameterized this. You could change the source by modifying this - https://github.com/Esri/arcgis-runtime-toolkit-qt/blob/master/Imports/ArcGIS/Runtime/Toolkit/Controls/Callout.qml#L402
Give it a try and let us know.
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