Clip geometry

<UserControl x:Class="ArcGIS.WinUI.Samples.ClipGeometry.ClipGeometry"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:MapView x:Name="MyMapView" />
        <Border Style="{StaticResource BorderStyle}">
            <Button x:Name="ClipButton"
                    HorizontalAlignment="Stretch"
                    Click="ClipButton_Click"
                    Content="Clip" />
        </Border>
    </Grid>
</UserControl>

// Copyright 2018 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
using Microsoft.UI.Xaml;
using System.Linq;

namespace ArcGIS.WinUI.Samples.ClipGeometry
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Clip geometry",
        category: "Geometry",
        description: "Clip a geometry with another geometry.",
        instructions: "Click the \"Clip\" button to clip the blue graphic with the red dashed envelopes.",
        tags: new[] { "analysis", "clip", "geometry" })]
    public partial class ClipGeometry
    {
        // Graphics overlay to display input geometries for the clip operation.
        private GraphicsOverlay _inputGeometriesGraphicsOverlay;

        // Graphics overlay to display the resulting geometries from the three GeometryEngine.Clip operations.
        private GraphicsOverlay _clipAreasGraphicsOverlay;

        // Graphics to represent geometry involved in the clip operation.
        private Graphic _coloradoGraphic;
        private Graphic _outsideGraphic;
        private Graphic _containedGraphic;
        private Graphic _intersectingGraphic;

        private bool _clipped;

        public ClipGeometry()
        {
            InitializeComponent();
            Initialize();
        }

        private void Initialize()
        {
            // Create a graphics overlay to hold the input geometries for the clip operation.
            _inputGeometriesGraphicsOverlay = new GraphicsOverlay();

            // Add the input geometries graphics overlay to the MapView.
            MyMapView.GraphicsOverlays.Add(_inputGeometriesGraphicsOverlay);

            // Create a graphics overlay to hold the resulting geometries from the three GeometryEngine.Clip operations.
            _clipAreasGraphicsOverlay = new GraphicsOverlay();

            // Add the resulting geometries graphics overlay to the MapView.
            MyMapView.GraphicsOverlays.Add(_clipAreasGraphicsOverlay);

            // Create a simple line symbol for the 1st parameter of the GeometryEngine.Clip operation - it follows the
            // boundary of Colorado.
            SimpleLineSymbol coloradoSimpleLineSymbol = new SimpleLineSymbol(
                SimpleLineSymbolStyle.Solid, System.Drawing.Color.Blue, 4);

            // Create the color that will be used as the fill for the Colorado graphic. It will be a semi-transparent, blue color.
            System.Drawing.Color coloradoFillColor = System.Drawing.Color.FromArgb(34, 0, 0, 255);

            // Create the simple fill symbol for the Colorado graphic - comprised of a fill style, fill color and outline.
            SimpleFillSymbol coloradoSimpleFillSymbol = new SimpleFillSymbol(
                SimpleFillSymbolStyle.Solid, coloradoFillColor, coloradoSimpleLineSymbol);

            // Create the geometry of the Colorado graphic.
            Envelope colorado = new Envelope(
                new MapPoint(-11362327.128340, 5012861.290274, SpatialReferences.WebMercator),
                new MapPoint(-12138232.018408, 4441198.773776, SpatialReferences.WebMercator));

            // Create the graphic for Colorado - comprised of a polygon shape and fill symbol.
            _coloradoGraphic = new Graphic(colorado, coloradoSimpleFillSymbol);

            // Add the Colorado graphic to the input geometries graphics overlay collection.
            _inputGeometriesGraphicsOverlay.Graphics.Add(_coloradoGraphic);

            // Create a simple line symbol for the three different clip geometries.
            SimpleLineSymbol clipGeomtriesSimpleLineSymbol = new SimpleLineSymbol(
                SimpleLineSymbolStyle.Dot, System.Drawing.Color.Red, 5);

            // Create an envelope outside Colorado.
            Envelope outsideEnvelope = new Envelope(
                new MapPoint(-11858344.321294, 5147942.225174, SpatialReferences.WebMercator),
                new MapPoint(-12201990.219681, 5297071.577304, SpatialReferences.WebMercator));

            // Create the graphic for an envelope outside Colorado - comprised of a polyline shape and line symbol.
            _outsideGraphic = new Graphic(outsideEnvelope, clipGeomtriesSimpleLineSymbol);

            // Add the envelope outside Colorado graphic to the graphics overlay collection.
            _inputGeometriesGraphicsOverlay.Graphics.Add(_outsideGraphic);

            // Create an envelope intersecting Colorado.
            Envelope intersectingEnvelope = new Envelope(
                new MapPoint(-11962086.479298, 4566553.881363, SpatialReferences.WebMercator),
                new MapPoint(-12260345.183558, 4332053.378376, SpatialReferences.WebMercator));

            // Create the graphic for an envelope intersecting Colorado - comprised of a polyline shape and line symbol.
            _intersectingGraphic = new Graphic(intersectingEnvelope, clipGeomtriesSimpleLineSymbol);

            // Add the envelope intersecting Colorado graphic to the graphics overlay collection.
            _inputGeometriesGraphicsOverlay.Graphics.Add(_intersectingGraphic);

            // Create a envelope inside Colorado.
            Envelope containedEnvelope = new Envelope(
                new MapPoint(-11655182.595204, 4741618.772994, SpatialReferences.WebMercator),
                new MapPoint(-11431488.567009, 4593570.068343, SpatialReferences.WebMercator));

            // Create the graphic for an envelope inside Colorado - comprised of a polyline shape and line symbol.
            _containedGraphic = new Graphic(containedEnvelope, clipGeomtriesSimpleLineSymbol);

            // Add the envelope inside Colorado graphic to the graphics overlay collection.
            _inputGeometriesGraphicsOverlay.Graphics.Add(_containedGraphic);

            // Get the extent of all of the graphics in the graphics overlay.
            Geometry visibleExtent = GeometryEngine.CombineExtents(_inputGeometriesGraphicsOverlay.Graphics.Select(graphic => graphic.Geometry));

            // Create the map for the MapView.
            MyMapView.Map = new Map(BasemapStyle.ArcGISTopographic) { InitialViewpoint = new Viewpoint(visibleExtent) };
        }

        private void ClipButton_Click(object sender, RoutedEventArgs e)
        {
            if (!_clipped)
            {
                ClipGraphics();
                _clipped = true;
            }
            else
            {
                Reset();
                _clipped = false;
            }

            ClipButton.Content = _clipped ? "Reset" : "Clip";
        }

        private void ClipGraphics()
        {
            // Remove the Colorado graphic from the input geometries graphics overlay collection. That way it will be easier
            // to see the clip versions of the GeometryEngine.Clip operation.
            _inputGeometriesGraphicsOverlay.Graphics.Remove(_coloradoGraphic);

            // Loop through each graphic in the input geometries for the clip operation.
            foreach (Graphic graphic in _inputGeometriesGraphicsOverlay.Graphics)
            {
                // Perform the clip operation. The first parameter of the clip operation will always be the Colorado graphic.
                // The second parameter of the clip operation will be one of the 3 different clip geometries (_outsideGraphic,
                // _containedGraphic, or _intersectingGraphic).
                Geometry myGeometry = _coloradoGraphic.Geometry.Clip((Envelope)graphic.Geometry);

                // Only work on returned geometries that are not null.
                if (myGeometry != null)
                {
                    // Create the graphic as a result of the clip operation using the same symbology that was defined for
                    // the _coloradoGraphic defined in the Initialize() method previously.
                    Graphic clippedGraphic = new Graphic(myGeometry, _coloradoGraphic.Symbol);

                    // Add the clipped graphic to the clip areas graphics overlay collection.
                    _clipAreasGraphicsOverlay.Graphics.Add(clippedGraphic);
                }
            }
        }

        private void Reset()
        {
            // Add the colorado graphic.
            _inputGeometriesGraphicsOverlay.Graphics.Add(_coloradoGraphic);

            // Remove the clip graphics.
            _clipAreasGraphicsOverlay.Graphics.Clear();
        }
    }
}