taler-ios

Image+fallback.swift (2512B)

---

 /* MIT License
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in all
  * copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *
  */
 import SwiftUI
 
 extension Image {
     init(_ name: String, _ sysName: String, fallback: String = SYSTEM_DUMMY1) {
         if let uiImage = UIImage(named: name) {
             self.init(uiImage: uiImage)
         } else if let sysImage = UIImage(systemName: sysName) {
             self.init(uiImage: sysImage)
         } else {
             self.init(systemName: fallback)
         }
     }
 
     /// Decode an `ImageDataUrl` as the protocol defines it: a data URL with an explicit
     /// mediatype (`image/png` or `image/jpeg`) and the `base64` parameter.
     /// Anything else must be rejected without ever being resolved: the string comes from
     /// the merchant, and `NSData(contentsOf:)` would *fetch* an `http(s):` URL - blocking
     /// the main thread and telling the merchant when (and how often) the user looks at
     /// the transaction - or read a local file for a `file:` URL.
     init?(imageBase64: String) {
         let anchored: String.CompareOptions = [.caseInsensitive, .anchored]
         guard let dataUrlPrefix = imageBase64.range(of: "data:image/png;base64,", options: anchored)
                                ?? imageBase64.range(of: "data:image/jpeg;base64,", options: anchored),
               let data = Data(base64Encoded: String(imageBase64[dataUrlPrefix.upperBound...])),
               let uiImage = UIImage(data: data)
         else { return nil }
 
         self.init(uiImage: uiImage)
     }
 }