From 10dda21dab2f506fbd212c455368ee0618c041ff Mon Sep 17 00:00:00 2001
From: Andy Uhnak <andyuhnak@gmail.com>
Date: Tue, 28 Jun 2022 18:11:22 +0100
Subject: [PATCH] Use ZXing library to generate QR codes

---
 ...cationVerifyByScanningViewController.swift |  8 +++-
 Riot/Modules/QRCode/QRCodeGenerator.swift     | 41 ++++++++-----------
 changelog.d/6358.bugfix                       |  1 +
 3 files changed, 25 insertions(+), 25 deletions(-)
 create mode 100644 changelog.d/6358.bugfix

diff --git a/Riot/Modules/KeyVerification/Common/Verify/Scanning/KeyVerificationVerifyByScanningViewController.swift b/Riot/Modules/KeyVerification/Common/Verify/Scanning/KeyVerificationVerifyByScanningViewController.swift
index c68e4f3586..c56d0fc0e0 100644
--- a/Riot/Modules/KeyVerification/Common/Verify/Scanning/KeyVerificationVerifyByScanningViewController.swift
+++ b/Riot/Modules/KeyVerification/Common/Verify/Scanning/KeyVerificationVerifyByScanningViewController.swift
@@ -17,6 +17,7 @@
  */
 
 import UIKit
+import MatrixSDK
 
 final class KeyVerificationVerifyByScanningViewController: UIViewController {
     
@@ -215,7 +216,12 @@ final class KeyVerificationVerifyByScanningViewController: UIViewController {
     
     private func qrCodeImage(from data: Data) -> UIImage? {
         let codeGenerator = QRCodeGenerator()
-        return codeGenerator.generateCode(from: data, with: self.codeImageView.frame.size)
+        do {
+            return try codeGenerator.generateCode(from: data, with: codeImageView.frame.size)
+        } catch {
+            MXLog.error("[KeyVerificationVerifyByScanningViewController] qrCodeImage: cannot generate QR code - \(error)")
+            return nil
+        }
     }
     
     private func presentQRCodeReader(animated: Bool) {
diff --git a/Riot/Modules/QRCode/QRCodeGenerator.swift b/Riot/Modules/QRCode/QRCodeGenerator.swift
index f3ad32c054..4ac8e6f6ed 100644
--- a/Riot/Modules/QRCode/QRCodeGenerator.swift
+++ b/Riot/Modules/QRCode/QRCodeGenerator.swift
@@ -15,36 +15,29 @@
  */
 
 import Foundation
+import ZXingObjC
 
 final class QRCodeGenerator {
-    
-    // MARK: - Constants
-    
-    private enum Constants {
-        static let qrCodeGeneratorFilter = "CIQRCodeGenerator"
-        static let qrCodeInputCorrectionLevel = "M"
+    enum Error: Swift.Error {
+        case cannotCreateImage
     }
     
-    // MARK: - Public
-    
-    func generateCode(from data: Data, with size: CGSize) -> UIImage? {
-        guard let filter = CIFilter(name: Constants.qrCodeGeneratorFilter) else {
-            return nil
-        }
-        
-        filter.setValue(data, forKey: "inputMessage")
-        filter.setValue(Constants.qrCodeInputCorrectionLevel, forKey: "inputCorrectionLevel") // Be sure to use same error resilience level as other platform
+    func generateCode(from data: Data, with size: CGSize) throws -> UIImage {
+        let writer = ZXMultiFormatWriter()
+        let endodedString = String(data: data, encoding: .isoLatin1)
+        let scale = UIScreen.main.scale
+        let bitMatrix = try writer.encode(
+            endodedString,
+            format: kBarcodeFormatQRCode,
+            width: Int32(size.width * scale),
+            height: Int32(size.height * scale),
+            hints: ZXEncodeHints()
+        )
         
-        guard let ciImage = filter.outputImage else {
-            return nil
+        guard let cgImage = ZXImage(matrix: bitMatrix).cgimage else {
+            throw Error.cannotCreateImage
         }
         
-        let scaleX = size.width/ciImage.extent.size.width
-        let scaleY = size.height/ciImage.extent.size.height
-        
-        let transform = CGAffineTransform(scaleX: scaleX, y: scaleY)
-            
-        let transformedCIImage = ciImage.transformed(by: transform)
-        return UIImage(ciImage: transformedCIImage)
+        return UIImage(cgImage: cgImage)
     }
 }
diff --git a/changelog.d/6358.bugfix b/changelog.d/6358.bugfix
new file mode 100644
index 0000000000..a0e99dd206
--- /dev/null
+++ b/changelog.d/6358.bugfix
@@ -0,0 +1 @@
+Cross-Signing: Use ZXing library to generate QR codes