SwiftUIで画像をピンチで拡大する（UIImageView + UIScrollView）

April 7, 2022

SwiftUIで画像をピンチで拡大する方法です。 UIImageViewとUIScrollViewを使って画像をピンチで拡大します。

他にはこのような方法があります。

Pinch and Zoom

	import SwiftUI

	struct ContentView: View {
	var body: some View {
	ImageViewer(imageName: "icon")
	.ignoresSafeArea(.all, edges: .all)
	}
	}

view raw ContentView.swift hosted with ❤ by GitHub

	import SwiftUI

	struct ImageViewer: UIViewRepresentable {
	let imageName: String

	func makeUIView(context: Context) -> UIImageViewerView {
	let view = UIImageViewerView(imageName: imageName)
	return view
	}

	func updateUIView(_ uiView: UIImageViewerView, context: Context) {}
	}

view raw ImageViewer.swift hosted with ❤ by GitHub

	import UIKit

	public class UIImageViewerView: UIView {
	private let imageName: String
	private let scrollView: UIScrollView = UIScrollView()
	private let imageView: UIImageView = UIImageView()

	required init(imageName: String) {
	self.imageName = imageName
	super.init(frame: .zero)

	scrollView.delegate = self
	scrollView.maximumZoomScale = 3.0
	scrollView.minimumZoomScale = 1.0
	// if you want to disable indicater
	// scrollView.showsHorizontalScrollIndicator = false
	// scrollView.showsVerticalScrollIndicator = false
	addSubview(scrollView)

	imageView.image = UIImage(named: imageName)
	imageView.contentMode = .scaleAspectFit
	scrollView.addSubview(imageView)
	}

	required init?(coder: NSCoder) {
	fatalError("init(coder:) has not been implemented")
	}


	public override func layoutSubviews() {
	super.layoutSubviews()
	scrollView.frame = bounds
	imageView.frame = scrollView.frame
	}
	}

	extension UIImageViewerView: UIScrollViewDelegate {
	public func viewForZooming(in scrollView: UIScrollView) -> UIView? {
	return imageView
	}
	}