topic Re: Add a floating graphic to Map in ArcGIS Pro SDK Questions

Add a floating graphic to Map

BrianBulla — Thu, 28 Jul 2022 13:31:47 GMT

Hi,

Is it possible to add a graphic to the active Map that floats in space and doesn't change position when panning the map? What I want to do is have a cross-hair type graphic centred around the centre of the map, and when the user pans around I will then use the Maps camera co-ordinate to do things with.

Hopefully that makes sense. I've added graphics before, but they've always been tied to a specific location on the map, and hence move with the map when panning. I kind of want the opposite effect.

Re: Add a floating graphic to Map

CharlesMacleod — Fri, 29 Jul 2022 21:54:33 GMT

you want a "MapViewOverlayControl". It is, essentially, a wrapper around a "standard" WPF User Control that u can add to the MapView control overlay. This overlay is used by Pro for user control content (as opposed to graphics elements content) - such as the Time slider, Edit sketch toolbar, Navigation tool "compass/navigator", and so on that sits "on top of" the map view.

To use it, create a user control - in this case it sounds like it will be something like a WPF canvas that contains your cross-hair image, centered. Wrap the user control with a MapViewOverlayControl and then add _that_ to the map view control overlay with mapView.AddOverlayerControl(....) : MapViewOverlayControl

You should also look at the scribble control sample - it uses the map view overlay to hold a scribble control allowing users to "scribble" or "annotate" markup directly on top of the mapview (via a MapViewOverlayControl wrapping the scribble control). https://github.com/Esri/arcgis-pro-sdk-community-samples/tree/master/Map-Exploration/ScribbleControl_ArcGISPro

Your code to add the overlay control will look something like this:

var crossHairControl = new CrossHairControl(); //your user control //do any required configuration upfront crossHairControl.Foo = ....; crossHairControl.Bar = ....; //Create a MapViewOverlayControl. var mapViewOverlayControl = new MapViewOverlayControl( crossHairControl, true, true, true, OverlayControlRelativePosition.Center, .5, .8); //Add to the active map view MapView.Active.AddOverlayControl(mapViewOverlayControl);

Re: Add a floating graphic to Map

Wolf — Sat, 30 Jul 2022 16:06:23 GMT

Charlie's suggestion is the way to go, however, you have to compute the x/y ratios to position the user control in the middle of the screen. For that you have the use the active mapview's GetViewSize().

if (MapView.Active == null) return; var mapView = MapView.Active; var crossHairControl = new CrossHairControl(); // use the active mapview to get the size of the mapview display var xRatio = 0.0; var yRatio = 0.0; var viewSize = mapView.GetViewSize(); if (viewSize.Width != 0.0 && viewSize.Height != 0.0) { var xPosition = viewSize.Width / 2; var yPosition = viewSize.Height / 2; // now offset for 1/2 of the user control's size xPosition -= 16; yPosition -= 16; xRatio = xPosition / viewSize.Width; yRatio = yPosition / viewSize.Height; } // Create a MapViewOverlayControl using the user control var mapViewOverlayControl = new MapViewOverlayControl( crossHairControl, true, false, false, OverlayControlRelativePosition.Center, xRatio, yRatio); //Add to the active map view mapView.AddOverlayControl(mapViewOverlayControl);

I attached my sample add-in, but the result should look like this:

Re: Add a floating graphic to Map

BrianBulla — Tue, 02 Aug 2022 14:39:10 GMT

Thanks guys. The sample code you both have given is a great help. One issue I am having is adding the crosshair using a CheckBox in my WPF Dockpane. The code seems to run, but then I get an exception saying "page can only have window or frame as parent".

In my Dockpane.xaml.cs I have this (basically the same as Wolf's code), and then the exception happens after the last line runs. The code seems to be calculating the width/height ok so it seems like I can interact with the MapView.

Any help is appreciated.

private void chkCrossHair_Checked(object sender, RoutedEventArgs e) { //draw a cross-hair in centre of active map if (MapView.Active == null) return; var mapView = MapView.Active; var crossHairControl = new CrossHairControl(); //use the active mapview to get the size of the mapview display var xRatio = 0.0; var yRatio = 0.0; var viewSize = mapView.GetViewSize(); if (viewSize.Width != 0.0 && viewSize.Height != 0.0) { var xPosition = viewSize.Width / 2; var yPosition = viewSize.Height / 2; // now offset for 1/2 of the user control's size xPosition -= 16; yPosition -= 16; xRatio = xPosition / viewSize.Width; yRatio = yPosition / viewSize.Height; } // Create a MapViewOverlayControl using the user control var mapViewOverlayControl = new MapViewOverlayControl( crossHairControl, true, false, false, OverlayControlRelativePosition.Center, xRatio, yRatio); //Add to the active map view mapView.AddOverlayControl(mapViewOverlayControl); }

Re: Add a floating graphic to Map

CharlesMacleod — Tue, 02 Aug 2022 16:10:47 GMT

you have a threading issue. Usually an InvalidOperation exception is thrown when u create something on the _background_ thread that needs to be created on the UI thread (the reverse of most cases w the Pro SDK which do require u to use the QTR).

However it's not possible to tell from just this snippet. Make sure that the complete sequence occurs on the UI thread in this case.

Re: Add a floating graphic to Map

Wolf — Tue, 02 Aug 2022 18:09:02 GMT

Like Charles said we don't have enough code to see the problem, but i would also check your CrossHairControl and make sure that mapViewOverlayControl is defined.

Re: Add a floating graphic to Map

BrianBulla — Tue, 02 Aug 2022 19:14:49 GMT

Thanks guys. So the problem was with my CrossHairControl. Once I deleted it and created a new one, all is good. No issues with the threading. Thanks for all your help with this!!