MVC Map link multiple markers with arrow line.

[Bhumi]

Hi,

I am using Kendo MVC Map to display transaction data. With the reference of https://docs.telerik.com/kendo-ui/controls/diagrams-and-maps/map/how-to/link-marker-to-location, I am able to draw a path between markers, but I want to show an arrow on the path of map. Below is the code I am using to display map,

<div id="transactionMap">
    @(Html.Kendo().Map()
.Name("map")
.Center(43.76398900, -79.54862200)
.Zoom(15)
.Layers(layers =>
{
    layers.Add()
        .Type(MapLayerType.Tile)
        .UrlTemplate("https://#= subdomain #.tile.openstreetmap.org/#= zoom #/#= x #/#= y #.png")
        .Subdomains("a", "b", "c")
        .Attribution("&copy; <a href='https://osm.org/copyright'>OpenStreetMap contributors</a>." +
                     "Tiles courtesy of <a href='https://www.opencyclemap.org/'>Andy Allan</a>")
        .ZIndex(0);

    layers.Add()
        .Style(style => style.Fill(fill => fill.Opacity(0.2)))
        .Type(MapLayerType.Shape)
        .ZIndex(1);

    layers.Add()
        .Type(MapLayerType.Marker)
        .DataSource(dataSource => dataSource
              .Read(read => read.Action("Transaction_Read", "TestReports").Data("TripLogMarkerParam").Type(HttpVerbs.Get))
        )
        .LocationField("LatLng")
        .TitleField("Name")
        
        .ZIndex(2);


})
.Events(e=>e.Reset("onResetMap")   
       ))
</div>

<script src="@Url.Content("~/Content/dataviz/map/js/chroma.min.js")"></script>
<script>
    var geom = kendo.geometry;
    var draw = kendo.drawing;
            
    function TripLogMarkerParam() {

        return {
            tripId: @ViewBag.tripId,
            fromTripLogId: @ViewBag.fromTripLogId,
            toTripLogId: @ViewBag.ToTripLogId
        };

    }

    function onResetMap(e) {
        var map = e.sender;
        var markers = map.layers[2].items;

        for (var i = 0; i < markers.length - 1; i++) {

            linkMarker(map, markers[i], markers[i + 1]);
        }

    }

   
    function linkMarker(map, marker, nextMarker) {
        var dataFrom = map.locationToView(marker.location());
        var nextDataFrom = map.locationToView(nextMarker.location());

        var shapeLayer = map.layers[1];
        var line = new kendo.dataviz.drawing.Path({
            stroke: {
                color: "#FF0000",
                width: 2,
                lineCap: "round"
            }
            
        });
        line.moveTo(dataFrom).lineTo(nextDataFrom);          
        shapeLayer.surface.draw(line);
    }
</script>

[Ivan Danchev]

Hi Bhumi,

Drawing allows connecting to markers with a line, but it doesn't have an arrow shape. This means that drawing an arrow would require drawing a line and a separate triangle for the arrow head:

//...
shapeLayer.surface.draw(line);

var triangle = new kendo.drawing.Path({
    fill: {
        color: "#FF0000"
    }
}).moveTo(nextDataFrom.x + 2, nextDataFrom.y).lineTo(nextDataFrom.x + 20, nextDataFrom.y + 10).lineTo(nextDataFrom.x + 2, nextDataFrom.y + 20).close();

shapeLayer.surface.draw(triangle);

However, this is problematic since the starting point would be the second marker (nextDataFrom), but that is just one point and it is not enough to determine how the arrow should be oriented. Thus, achieving this requirement would require a custom solution.

Regards,
Ivan Danchev
Progress Telerik