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// Copyright 2021 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.
import UIKit
import ArcGIS
class ExportVectorTilesViewController: UIViewController {
// MARK: Storyboard views
/// The map view managed by the view controller.
@IBOutlet var mapView: AGSMapView! {
didSet {
mapView.map = AGSMap(basemapStyle: .arcGISStreetsNight)
// Set the viewpoint.
mapView.setViewpoint(AGSViewpoint(latitude: 34.049, longitude: -117.181, scale: 1e4))
}
}
/// A view to emphasize the extent of exported tile layer.
@IBOutlet var extentView: UIView! {
didSet {
extentView.layer.borderColor = UIColor.red.cgColor
extentView.layer.borderWidth = 2
}
}
/// A bar button to initiate the download task.
@IBOutlet var exportVectorTilesButton: UIBarButtonItem!
@IBOutlet var progressView: UIProgressView!
@IBOutlet var progressLabel: UILabel!
@IBOutlet var progressParentView: UIView!
@IBOutlet var cancelButton: UIButton!
// MARK: Properties
/// The resulting vector tiled layer.
var vectorTiledLayer: AGSArcGISVectorTiledLayer?
/// The extent of the map that is to be exported.
var extent: AGSEnvelope?
/// The export task to request the tile package with the same URL as the tile layer.
var exportVectorTilesTask: AGSExportVectorTilesTask?
/// An export job to download the tile package.
var job: AGSExportVectorTilesJob? {
didSet {
// Remove key-value observation.
progressObservation = nil
exportVectorTilesButton.isEnabled = job == nil
// Refresh the progress view according to the job status.
updateProgressViewUI()
// Observe the job's progress.
progressView.observedProgress = job?.progress
// Observe the localized description in order to update the text label.
progressObservation = job?.progress.observe(\.localizedDescription, options: .initial) { [weak self] progress, _ in
DispatchQueue.main.async {
// Update the progress label.
self?.progressLabel.text = progress.localizedDescription
}
}
}
}
/// A URL to the temporary directory to temporarily store the exported vector tile package.
let vtpkTemporaryURL: URL
/// A URL to the temporary directory to temporarily store the style item resources.
let styleTemporaryURL: URL
/// A directory to temporarily store all items.
let temporaryDirectory: URL
/// Observation to track the export vector tiles job.
private var progressObservation: NSKeyValueObservation?
required init?(coder: NSCoder) {
temporaryDirectory = FileManager.default.temporaryDirectory.appendingPathComponent(ProcessInfo().globallyUniqueString)
try? FileManager.default.createDirectory(at: temporaryDirectory, withIntermediateDirectories: false)
vtpkTemporaryURL = temporaryDirectory
.appendingPathComponent("myTileCache", isDirectory: false)
.appendingPathExtension("vtpk")
styleTemporaryURL = temporaryDirectory
.appendingPathComponent("styleItemResources", isDirectory: true)
super.init(coder: coder)
}
// MARK: Methods
/// Initiate the `AGSExportVectorTilesTask` to download a tile package.
/// - Parameters:
/// - exportTask: An `AGSExportVectorTilesTask` to run the export job.
/// - vectorTileCacheURL: A URL to where the tile package should be saved.
func initiateDownload(exportTask: AGSExportVectorTilesTask, vectorTileCacheURL: URL) {
// Set the max scale parameter to 10% of the map's scale to limit the
// number of tiles exported to within the vector tiled layer's max tile export limit.
let maxScale = mapView.mapScale * 0.1
// Get current area of interest marked by the extent view.
let areaOfInterest = envelope(for: extentView)
// Get the parameters by specifying the selected area and vector tiled layer's max scale as maxScale.
exportTask.defaultExportVectorTilesParameters(withAreaOfInterest: areaOfInterest, maxScale: maxScale) { [weak self] parameters, error in
guard let self = self, let exportVectorTilesTask = self.exportVectorTilesTask else { return }
if let params = parameters {
// Start exporting the tiles with the resulting parameters.
self.exportVectorTiles(exportTask: exportVectorTilesTask, parameters: params, vectorTileCacheURL: vectorTileCacheURL)
} else if let error = error {
self.presentAlert(error: error)
}
}
}
/// Export vector tiles with the `AGSExportVectorTilesJob` from the export task.
/// - Parameters:
/// - exportTask: An `AGSExportVectorTilesTask` to run the export job.
/// - parameters: The parameters of the export task.
/// - vectorTileCacheURL: A URL to where the tile package is saved.
func exportVectorTiles(exportTask: AGSExportVectorTilesTask, parameters: AGSExportVectorTilesParameters, vectorTileCacheURL: URL) {
// Create the job with the parameters and download URLs.
let job = exportTask.exportVectorTilesJob(with: parameters, vectorTileCacheDownloadFileURL: vtpkTemporaryURL, itemResourceCacheDownloadDirectory: styleTemporaryURL)
self.job = job
// Start the job.
job.start(statusHandler: nil) { [weak self] (result, error) in
guard let self = self else { return }
self.job = nil
if let result = result,
let tileCache = result.vectorTileCache,
let itemResourceCache = result.itemResourceCache {
self.updateProgressViewUI()
// Create the vector tiled layer with the tile cache and item resource cache.
self.vectorTiledLayer = AGSArcGISVectorTiledLayer(vectorTileCache: tileCache, itemResourceCache: itemResourceCache)
// Set the extent.
self.extent = parameters.areaOfInterest as? AGSEnvelope
self.performSegue(withIdentifier: "showResult", sender: nil)
} else if let error = error {
let nsError = error as NSError
if !(nsError.domain == NSCocoaErrorDomain && nsError.code == NSUserCancelledError) {
self.presentAlert(error: error)
}
}
}
}
/// Get the extent within the extent view for generating a vector tile package.
func envelope(for view: UIView) -> AGSEnvelope {
let frame = mapView.convert(view.frame, from: self.view)
let minPoint = mapView.screen(toLocation: CGPoint(x: frame.minX, y: frame.minY))
let maxPoint = mapView.screen(toLocation: CGPoint(x: frame.maxX, y: frame.maxY))
let extent = AGSEnvelope(min: minPoint, max: maxPoint)
return extent
}
/// Update the progress view accordingly.
func updateProgressViewUI() {
let isJobNil = job == nil
mapView.interactionOptions.isEnabled = isJobNil
progressParentView.isHidden = isJobNil
}
/// Remove temporary files that are created for each job.
func removeTemporaryFiles() {
try? FileManager.default.removeItem(at: vtpkTemporaryURL)
try? FileManager.default.removeItem(at: styleTemporaryURL)
}
// MARK: Actions
@IBAction func exportTilesBarButtonTapped(_ sender: UIBarButtonItem) {
if let exportVectorTilesTask = exportVectorTilesTask,
let vectorTileSourceInfo = exportVectorTilesTask.vectorTileSourceInfo,
vectorTileSourceInfo.exportTilesAllowed {
// Try to download when exporting tiles is allowed.
initiateDownload(exportTask: exportVectorTilesTask, vectorTileCacheURL: vtpkTemporaryURL)
} else {
presentAlert(title: "Error", message: "Exporting tiles is not supported for the service.")
}
}
@IBAction func cancelAction() {
// Cancel export vector tiles job and remove the temporary files.
job?.progress.cancel()
removeTemporaryFiles()
}
// MARK: - Navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let navController = segue.destination as? UINavigationController,
let rootController = navController.viewControllers.first as? VectorTilePackageViewController {
// Display the view controller as a formsheet - specified for iPads.
rootController.modalPresentationStyle = .formSheet
rootController.isModalInPresentation = true
rootController.tiledLayerResult = vectorTiledLayer
rootController.extent = extent
rootController.delegate = self
}
}
// MARK: UIViewController
override func viewDidLoad() {
super.viewDidLoad()
mapView.map?.load { [weak self] _ in
guard let self = self else { return }
// Obtain the vector tiled layer and its URL from the baselayers.
guard let vectorTiledLayer = self.mapView.map?.basemap.baseLayers.firstObject as? AGSArcGISVectorTiledLayer,
let vectorTiledLayerURL = vectorTiledLayer.url else { return }
// The export task to request the tile package with the same URL as the tile layer.
let exportVectorTilesTask = AGSExportVectorTilesTask(url: vectorTiledLayerURL)
self.exportVectorTilesTask = exportVectorTilesTask
exportVectorTilesTask.load { [weak self] error in
guard let self = self else { return }
if let error = error {
self.presentAlert(error: error)
} else {
self.exportVectorTilesButton.isEnabled = true
}
}
}
// Add the source code button item to the right of navigation bar.
(navigationItem.rightBarButtonItem as! SourceCodeBarButtonItem).filenames = ["ExportVectorTilesViewController", "VectorTilePackageViewController"]
}
deinit {
try? FileManager.default.removeItem(at: temporaryDirectory)
}
}
extension ExportVectorTilesViewController: VectorTilePackageViewControllerDelegate {
func vectorTilePackageViewControllerDidFinish(_ controller: VectorTilePackageViewController) {
// Remove the downloaded vector tile package files after finishing viewing them.
removeTemporaryFiles()
}
}