Cut geometry

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// Copyright 2022 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
//
//   https://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.

import ArcGIS
import SwiftUI

struct CutGeometryView: View {
    /// A Boolean value indicating whether the geometry is cut.
    @State private var isGeometryCut = false

    /// The view model for the sample.
    @StateObject private var model = Model()

    var body: some View {
        MapView(map: model.map, graphicsOverlays: model.graphicsOverlays)
            .toolbar {
                ToolbarItem(placement: .bottomBar) {
                    Button(isGeometryCut ? "Reset" : "Cut") {
                        if isGeometryCut {
                            model.removeAllGraphics()
                        } else {
                            model.cutGeometry()
                        }
                        isGeometryCut.toggle()
                    }
                }
            }
    }
}

private extension CutGeometryView {
    /// The model used to store the geo model and other expensive objects
    /// used in this view.
    class Model: ObservableObject {
        /// A map with a topographic basemap style and an initial viewpoint of Lake Superior.
        let map: Map = {
            let map = Map(basemapStyle: .arcGISTopographic)
            map.initialViewpoint = Viewpoint(boundingGeometry: Geometry.lakeSuperiorPolygon)
            return map
        }()

        /// A graphics overlay containing the Lake Superior polygon and a border line.
        private let lakeGraphicsOverlay: GraphicsOverlay = {
            let lakeSuperiorGraphic = Graphic(
                geometry: .lakeSuperiorPolygon,
                symbol: SimpleFillSymbol(
                    color: .blue.withAlphaComponent(0.1),
                    outline: SimpleLineSymbol(style: .solid, color: .blue, width: 4)
                )
            )
            let borderGraphic = Graphic(
                geometry: .borderPolyline,
                symbol: SimpleLineSymbol(style: .dot, color: .red, width: 5)
            )
            return GraphicsOverlay(graphics: [lakeSuperiorGraphic, borderGraphic])
        }()

        /// The graphics overlay containing cut graphics.
        private let cutGraphicsOverlay = GraphicsOverlay()

        /// The graphics overlays used in this sample.
        var graphicsOverlays: [GraphicsOverlay] {
            return [lakeGraphicsOverlay, cutGraphicsOverlay]
        }

        /// Cuts geometry and adds resulting graphics.
        func cutGeometry() {
            // Cuts the Lake Superior polygon using the border polyline.
            let parts = GeometryEngine.cut(.lakeSuperiorPolygon, usingCutter: .borderPolyline)
            guard parts.count == 2,
                  let firstPart = parts.first,
                  let secondPart = parts.last else {
                return
            }
            // Creates the graphics for the Canadian and USA sides of Lake Superior.
            let canadaSideGraphic = Graphic(geometry: firstPart, symbol: SimpleFillSymbol(style: .backwardDiagonal, color: .green))
            let usaSideGraphic = Graphic(geometry: secondPart, symbol: SimpleFillSymbol(style: .forwardDiagonal, color: .yellow))
            // Adds the graphics to the graphics overlay.
            cutGraphicsOverlay.addGraphics([canadaSideGraphic, usaSideGraphic])
        }

        /// Removes all cut graphics.
        func removeAllGraphics() {
            cutGraphicsOverlay.removeAllGraphics()
        }
    }
}

private extension Geometry {
    /// A polygon representing the area of Lake Superior.
    static var lakeSuperiorPolygon: ArcGIS.Polygon {
        Polygon(
            points: [
                Point(x: -10254374.668616, y: 5908345.076380),
                Point(x: -10178382.525314, y: 5971402.386779),
                Point(x: -10118558.923141, y: 6034459.697178),
                Point(x: -9993252.729399, y: 6093474.872295),
                Point(x: -9882498.222673, y: 6209888.368416),
                Point(x: -9821057.766387, y: 6274562.532928),
                Point(x: -9690092.583250, y: 6241417.023616),
                Point(x: -9605207.742329, y: 6206654.660191),
                Point(x: -9564786.389509, y: 6108834.986367),
                Point(x: -9449989.747500, y: 6095091.726408),
                Point(x: -9462116.153346, y: 6044160.821855),
                Point(x: -9417652.665244, y: 5985145.646738),
                Point(x: -9438671.768711, y: 5946341.148031),
                Point(x: -9398250.415891, y: 5922088.336339),
                Point(x: -9419269.519357, y: 5855797.317714),
                Point(x: -9467775.142741, y: 5858222.598884),
                Point(x: -9462924.580403, y: 5902686.086985),
                Point(x: -9598740.325877, y: 5884092.264688),
                Point(x: -9643203.813979, y: 5845287.765981),
                Point(x: -9739406.633691, y: 5879241.702350),
                Point(x: -9783061.694736, y: 5922896.763395),
                Point(x: -9844502.151022, y: 5936640.023354),
                Point(x: -9773360.570059, y: 6019099.583107),
                Point(x: -9883306.649729, y: 5968977.105610),
                Point(x: -9957681.938918, y: 5912387.211662),
                Point(x: -10055501.612742, y: 5871965.858842),
                Point(x: -10116942.069028, y: 5884092.264688),
                Point(x: -10111283.079633, y: 5933406.315128),
                Point(x: -10214761.742852, y: 5888134.399970),
                Point(x: -10254374.668616, y: 5901877.659929)
            ],
            spatialReference: .webMercator
        )
    }
    /// A polyline representing the Canada/USA border.
    static var borderPolyline: Polyline {
        Polyline(
            points: [
                Point(x: -9981328.687124, y: 6111053.281447),
                Point(x: -9946518.044066, y: 6102350.620682),
                Point(x: -9872545.427566, y: 6152390.920079),
                Point(x: -9838822.617103, y: 6157830.083057),
                Point(x: -9446115.050097, y: 5927209.572793),
                Point(x: -9430885.393759, y: 5876081.440801),
                Point(x: -9415655.737420, y: 5860851.784463)
            ],
            spatialReference: .webMercator
        )
    }
}

#Preview {
    NavigationStack {
        CutGeometryView()
    }
}