taler-ios

PosQRView.swift (5221B)

---

 /*
  * This file is part of GNU Taler
  * (C) 2026 Bohdan, Volodymyr Potuzhnyi
  *
  * GNU Taler is free software; you can redistribute it and/or modify it under the
  * terms of the GNU General Public License as published by the Free Software
  * Foundation; either version 3, or (at your option) any later version.
  *
  * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
  */
 
 import SwiftUI
 import CoreImage.CIFilterBuiltins
 
 
 private let qrCornerRadius: CGFloat = 0.08
 private let qrStripeWidth: CGFloat = 0.025
 private let qrDataFraction: CGFloat = 0.88
 private let qrLogoFraction: CGFloat = 0.30 * qrDataFraction
 
 struct PosQRView: View {
     let text: String?
     let size: CGFloat
 
     @State private var qrImage: UIImage?
     @State private var showQR = false
 
     var body: some View {
         let cornerRadius = size * qrCornerRadius
         let qrSize = size * qrDataFraction
         let logoWidth = size * qrLogoFraction
 
         ZStack {
             RoundedRectangle(cornerRadius: cornerRadius)
                 .fill(.white)
                 .frame(width: size, height: size)
 
             SpinningBorder(size: size)
 
             if showQR, let qrImage {
                 Image(uiImage: qrImage)
                     .interpolation(.none)
                     .resizable()
                     .scaledToFit()
                     .frame(width: qrSize, height: qrSize)
                     .transition(.opacity)
 
                 Image("taler-logo-qr")
                     .resizable()
                     .scaledToFit()
                     .frame(width: logoWidth)
                     .transition(.opacity)
             }
         }
         .clipShape(RoundedRectangle(cornerRadius: cornerRadius))
         .animation(.easeIn(duration: 0.3), value: showQR)
         .onAppear {
             if let text {
                 generateQRAsync(from: text)
             }
         }
         .onChange(of: text) { newText in
             if let newText {
                 generateQRAsync(from: newText)
             } else {
                 showQR = false
                 qrImage = nil
             }
         }
     }
 
     private func generateQRAsync(from string: String) {
         let targetSize = size * qrDataFraction
         Task.detached(priority: .userInitiated) {
             let context = CIContext()
             let filter = CIFilter.qrCodeGenerator()
             filter.message = Data(string.utf8)
             filter.correctionLevel = "H"
             guard let ciImage = filter.outputImage else { return }
 
             let modules = ciImage.extent.width
             let scale = max(1, Int(ceil(Double(targetSize) / modules)))
             let transformed = ciImage.transformed(by: CGAffineTransform(scaleX: CGFloat(scale), y: CGFloat(scale)))
 
             guard let cgImage = context.createCGImage(transformed, from: transformed.extent) else { return }
             let image = UIImage(cgImage: cgImage)
 
             await MainActor.run {
                 qrImage = image
                 showQR = true
             }
         }
     }
 }
 
 private struct SpinningBorder: View {
     let size: CGFloat
     @State private var rotation: Double = 0
 
     private let stripeColor = Color(red: 0.188, green: 0.278, blue: 0.639)
 
     private var stripeSoft: Color {
         Color(
             red: 1.0 * 0.45 + 0.188 * 0.55,
             green: 1.0 * 0.45 + 0.278 * 0.55,
             blue: 1.0 * 0.45 + 0.639 * 0.55
         )
     }
 
     var body: some View {
         let cornerRadius = size * qrCornerRadius
         let stripeWidth = size * qrStripeWidth
 
         RoundedRectangle(cornerRadius: cornerRadius)
             .strokeBorder(
                 AngularGradient(
                     gradient: Gradient(stops: [
                         .init(color: .white, location: 0.00),
                         .init(color: .white, location: 0.05),
                         .init(color: stripeSoft, location: 0.09),
                         .init(color: stripeColor, location: 0.12),
                         .init(color: stripeSoft, location: 0.16),
                         .init(color: .white, location: 0.21),
                         .init(color: .white, location: 0.50),
                         .init(color: stripeSoft, location: 0.55),
                         .init(color: stripeColor, location: 0.59),
                         .init(color: stripeSoft, location: 0.62),
                         .init(color: .white, location: 0.66),
                         .init(color: .white, location: 1.00),
                     ]),
                     center: .center,
                     angle: .degrees(rotation)
                 ),
                 lineWidth: stripeWidth
             )
             .frame(width: size, height: size)
             .onAppear {
                 withAnimation(.linear(duration: 5.25).repeatForever(autoreverses: false)) {
                     rotation = 360
                 }
             }
     }
 }