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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 ClipGeometryView: View {
/// A Boolean value indicating whether the geometries are clipped.
@State private var geometriesAreClipped = false
/// A map with a topographic basemap style and an initial viewpoint of Colorado.
@StateObject private var map: Map = {
let map = Map(basemapStyle: .arcGISTopographic)
// Sets the initial viewpoint to Colorado and adds additional padding.
map.initialViewpoint = Viewpoint(targetExtent: .coloradoEnvelope.expanded(by: 2))
return map
}()
/// The graphics overlay containing an unclipped graphic of Colorado.
@StateObject private var coloradoGraphicsOverlay = GraphicsOverlay(
graphics: [
Graphic(geometry: .coloradoEnvelope, symbol: .coloradoFill)
]
)
/// The graphics overlay containing graphics of the other envelopes, outlined by a dotted red line.
@StateObject private var envelopesGraphicsOverlay = GraphicsOverlay(
graphics: Geometry.envelopes.map {
Graphic(geometry: $0, symbol: SimpleLineSymbol(style: .dot, color: .red, width: 3))
}
)
/// The graphics overlay containing clipped graphics.
@StateObject private var clippedGraphicsOverlay = GraphicsOverlay()
/// The unclipped graphic of Colorado.
private var coloradoGraphic: Graphic { coloradoGraphicsOverlay.graphics.first! }
/// Clips the geometry of Colorado to the given envelope.
/// - Parameter envelope: The envelope to clip the geometry of Colorado to.
/// - Returns: The clipped graphic.
private func clipColoradoGeometry(to envelope: Envelope) -> Graphic {
// Uses the geometry engine to create a new geometry for the area of
// Colorado that overlaps the given envelope.
let clippedGeometry = GeometryEngine.clip(coloradoGraphic.geometry!, to: envelope)
// Creates and returns the clipped graphic from the clipped geometry if there is an overlap.
return Graphic(geometry: clippedGeometry, symbol: .coloradoFill)
}
/// Clips geometries and adds resulting graphics.
private func clipGeometries() {
// Hides the Colorado graphic.
coloradoGraphic.isVisible = false
// Clips Colorado's geometry to each envelope.
let clippedGraphics = envelopesGraphicsOverlay.graphics.map { clipColoradoGeometry(to: $0.geometry as! Envelope) }
// Adds the clipped graphics.
clippedGraphicsOverlay.addGraphics(clippedGraphics)
}
/// Removes all clipped graphics.
private func reset() {
clippedGraphicsOverlay.removeAllGraphics()
coloradoGraphic.isVisible = true
}
var body: some View {
MapView(map: map, graphicsOverlays: [coloradoGraphicsOverlay, envelopesGraphicsOverlay, clippedGraphicsOverlay])
.toolbar {
ToolbarItem(placement: .bottomBar) {
Button(geometriesAreClipped ? "Reset" : "Clip") {
if geometriesAreClipped {
reset()
} else {
clipGeometries()
}
geometriesAreClipped.toggle()
}
}
}
}
}
private extension Symbol {
/// The simple fill symbol for Colorado graphics.
static var coloradoFill: SimpleFillSymbol {
SimpleFillSymbol(
color: .blue.withAlphaComponent(0.2),
outline: SimpleLineSymbol(
style: .solid,
color: .blue,
width: 2
)
)
}
}
private extension Geometry {
/// An envelope approximating the boundary of Colorado.
static var coloradoEnvelope: Envelope {
Envelope(
xMin: -11362327.1283,
yMin: 5012861.2903,
xMax: -12138232.0184,
yMax: 4441198.7738,
spatialReference: .webMercator
)
}
/// An envelope inside the boundary of Colorado.
static var containedEnvelope: Envelope {
Envelope(
xMin: -11655182.5952,
yMin: 4741618.773,
xMax: -11431488.567,
yMax: 4593570.0683,
spatialReference: .webMercator
)
}
/// An envelope intersecting the boundary of Colorado.
static var intersectingEnvelope: Envelope {
Envelope(
xMin: -11962086.4793,
yMin: 4566553.8814,
xMax: -12260345.1836,
yMax: 4332053.3784,
spatialReference: .webMercator
)
}
/// An envelope outside the boundary of Colorado.
static var outsideEnvelope: Envelope {
Envelope(
xMin: -11858344.3213,
yMin: 5147942.2252,
xMax: -12201990.2197,
yMax: 5297071.5773,
spatialReference: .webMercator
)
}
/// The envelopes to clip the geometry of Colorado to.
static var envelopes: [Envelope] {
return [.containedEnvelope, .intersectingEnvelope, .outsideEnvelope]
}
}
private extension Envelope {
/// Expands the envelope by a given factor.
func expanded(by factor: Double) -> Envelope {
let builder = EnvelopeBuilder(envelope: self)
builder.expand(factor: factor)
return builder.toGeometry()
}
}
