Fix broken avatar aspect ratio in the share sheet and notifications

The media repo serves thumbnails with the scale method, so avatars keep
their source aspect ratio. The system stretches whatever INImage we
donate to fill a circle, distorting any non-square avatar in the share
sheet's conversation suggestions (and notifications, which are donated
the same image).

Centre-crop donated avatars to a square before handing them to the
system, in both the timeline's send message intent donation and the
NSE's communication context.

ElementX/Sources/Other/Avatars.swift

@@ -8,6 +8,7 @@
 
 import Foundation
 import SwiftUI
+import UIKit
 
 enum Avatars {
     enum Size {
@@ -38,6 +39,28 @@ enum Avatars {
         }
     }
     
+    /// Media repo thumbnails are scaled, not cropped, so they keep the source's aspect
+    /// ratio. System UI (share sheet suggestions, notifications) stretches non-square
+    /// images to fill its circle, so centre-crop to a square before donating them.
+    nonisolated static func squareAvatarImageData(from data: Data) -> Data? {
+        guard let image = UIImage(data: data) else { return nil }
+
+        let side = min(image.size.width, image.size.height)
+        guard side > 0 else { return nil }
+
+        if image.size.width == image.size.height {
+            return data
+        }
+
+        let format = UIGraphicsImageRendererFormat()
+        format.scale = image.scale
+
+        return UIGraphicsImageRenderer(size: CGSize(width: side, height: side), format: format)
+            .pngData { _ in
+                image.draw(at: CGPoint(x: (side - image.size.width) / 2, y: (side - image.size.height) / 2))
+            }
+    }
+
     @MainActor
     static func generatePlaceholderAvatarImageData(name: String, id: String, size: CGSize) -> Data? {
         let image = PlaceholderAvatarImage(name: name, contentID: id)

ElementX/Sources/Services/Timeline/TimelineController/TimelineController.swift

@@ -650,8 +650,9 @@ class TimelineController: TimelineControllerProtocol {
         }
         
         if let avatarURL, let mediaSource = try? MediaSourceProxy(url: avatarURL, mimeType: nil) {
-            if case let .success(avatarData) = await mediaProvider.loadThumbnailForSource(source: mediaSource, size: .init(width: 100, height: 100)) {
-                sendMessageIntent.setImage(INImage(imageData: avatarData), forParameterNamed: \.speakableGroupName)
+            if case let .success(avatarData) = await mediaProvider.loadThumbnailForSource(source: mediaSource, size: .init(width: 100, height: 100)),
+               let squareAvatarData = Avatars.squareAvatarImageData(from: avatarData) {
+                sendMessageIntent.setImage(INImage(imageData: squareAvatarData), forParameterNamed: \.speakableGroupName)
             } else {
                 addPlacehoder()
             }

NSE/Sources/NotificationContentBuilder.swift

@@ -259,7 +259,9 @@ nonisolated struct NotificationContentBuilder {
            let mediaSource = icon.mediaSource {
             switch await mediaProvider.loadThumbnailForSource(source: mediaSource, size: .init(width: 100, height: 100)) {
             case .success(let data):
-                fetchedImage = INImage(imageData: data)
+                if let squareData = Avatars.squareAvatarImageData(from: data) {
+                    fetchedImage = INImage(imageData: squareData)
+                }
             case .failure(let error):
                 MXLog.error("Couldn't add sender icon: \(error)")
             }