Added blurhash and correct sizes to timeline images and animations throughout the app.

ElementX.xcodeproj/project.pbxproj

@@ -49,6 +49,7 @@
 		18ADC7FA27EB02D900A8C953 /* AttributedStringBuilder.swift in Sources */ = {isa = PBXBuildFile; fileRef = 18ADC7F927EB02D900A8C953 /* AttributedStringBuilder.swift */; };
 		18ADC7FE27EB033400A8C953 /* DTCoreText in Frameworks */ = {isa = PBXBuildFile; productRef = 18ADC7FD27EB033400A8C953 /* DTCoreText */; };
 		18ADC80627EB1ED100A8C953 /* UIFont+AttributedStringBuilder.m in Sources */ = {isa = PBXBuildFile; fileRef = 18ADC80427EB1ED100A8C953 /* UIFont+AttributedStringBuilder.m */; };
+		18BB170A27FC20D20074CBD6 /* BlurHashDecode.swift in Sources */ = {isa = PBXBuildFile; fileRef = 18BB170927FC20D20074CBD6 /* BlurHashDecode.swift */; };
 		18C5744C27E1D84000D70937 /* RoomProxyProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = 18C5744827E1D84000D70937 /* RoomProxyProtocol.swift */; };
 		18C5744D27E1D84000D70937 /* RoomProxy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 18C5744A27E1D84000D70937 /* RoomProxy.swift */; };
 		18C5744E27E1D84000D70937 /* MockRoomProxy.swift in Sources */ = {isa = PBXBuildFile; fileRef = 18C5744B27E1D84000D70937 /* MockRoomProxy.swift */; };
@@ -189,6 +190,7 @@
 		18ADC80527EB1ED100A8C953 /* UIFont+AttributedStringBuilder.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "UIFont+AttributedStringBuilder.h"; sourceTree = "<group>"; };
 		18ADC80727EB1EE200A8C953 /* ElementX-Bridging-Header.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "ElementX-Bridging-Header.h"; sourceTree = "<group>"; };
 		18BB170627FB74B30074CBD6 /* matrix-rust-components-swift */ = {isa = PBXFileReference; lastKnownFileType = wrapper; name = "matrix-rust-components-swift"; path = "../matrix-rust-components-swift"; sourceTree = "<group>"; };
+		18BB170927FC20D20074CBD6 /* BlurHashDecode.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = BlurHashDecode.swift; sourceTree = "<group>"; };
 		18C5744827E1D84000D70937 /* RoomProxyProtocol.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RoomProxyProtocol.swift; sourceTree = "<group>"; };
 		18C5744A27E1D84000D70937 /* RoomProxy.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RoomProxy.swift; sourceTree = "<group>"; };
 		18C5744B27E1D84000D70937 /* MockRoomProxy.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MockRoomProxy.swift; sourceTree = "<group>"; };
@@ -537,6 +539,7 @@
 			isa = PBXGroup;
 			children = (
 				184858EA27FAF6D300B8AC7B /* Benchmark.swift */,
+				18BB170927FC20D20074CBD6 /* BlurHashDecode.swift */,
 				18920C1827F3222E00A717B5 /* Colors.swift */,
 				18F2BA9A27D25B4000DD1988 /* Coordinator.swift */,
 				18DDB72D27EF936D000F1ABF /* MatrixEntitityRegex.swift */,
@@ -1003,6 +1006,7 @@
 				181A317B27F70AEB00B8305B /* EventBrief.swift in Sources */,
 				181A317927F703E300B8305B /* MockRoomSummary.swift in Sources */,
 				1850256F27B6A135002E6B18 /* AppDelegate.swift in Sources */,
+				18BB170A27FC20D20074CBD6 /* BlurHashDecode.swift in Sources */,
 				18F2BAE627D25B4000DD1988 /* NavigationRouterType.swift in Sources */,
 				184858EB27FAF6D300B8AC7B /* Benchmark.swift in Sources */,
 				18F2BAE927D25B4000DD1988 /* ActivityPresentable.swift in Sources */,

ElementX/Sources/Other/BlurHashDecode.swift

@@ -0,0 +1,150 @@
+import UIKit
+
+// swiftlint:disable all
+
+extension UIImage {
+    public convenience init?(blurHash: String, size: CGSize, punch: Float = 1) {
+        guard blurHash.count >= 6 else { return nil }
+
+		let sizeFlag = String(blurHash[0]).decode83()
+		let numY = (sizeFlag / 9) + 1
+		let numX = (sizeFlag % 9) + 1
+
+		let quantisedMaximumValue = String(blurHash[1]).decode83()
+        let maximumValue = Float(quantisedMaximumValue + 1) / 166
+
+        guard blurHash.count == 4 + 2 * numX * numY else { return nil }
+
+        let colours: [(Float, Float, Float)] = (0 ..< numX * numY).map { i in
+            if i == 0 {
+				let value = String(blurHash[2 ..< 6]).decode83()
+                return decodeDC(value)
+            } else {
+                let value = String(blurHash[4 + i * 2 ..< 4 + i * 2 + 2]).decode83()
+                return decodeAC(value, maximumValue: maximumValue * punch)
+            }
+        }
+
+        let width = Int(size.width)
+        let height = Int(size.height)
+        let bytesPerRow = width * 3
+        guard let data = CFDataCreateMutable(kCFAllocatorDefault, bytesPerRow * height) else { return nil }
+        CFDataSetLength(data, bytesPerRow * height)
+        guard let pixels = CFDataGetMutableBytePtr(data) else { return nil }
+
+        for y in 0 ..< height {
+            for x in 0 ..< width {
+                var r: Float = 0
+                var g: Float = 0
+                var b: Float = 0
+
+                for j in 0 ..< numY {
+                    for i in 0 ..< numX {
+                        let basis = cos(Float.pi * Float(x) * Float(i) / Float(width)) * cos(Float.pi * Float(y) * Float(j) / Float(height))
+                        let colour = colours[i + j * numX]
+                        r += colour.0 * basis
+                        g += colour.1 * basis
+                        b += colour.2 * basis
+                    }
+                }
+
+                let intR = UInt8(linearTosRGB(r))
+                let intG = UInt8(linearTosRGB(g))
+                let intB = UInt8(linearTosRGB(b))
+
+                pixels[3 * x + 0 + y * bytesPerRow] = intR
+                pixels[3 * x + 1 + y * bytesPerRow] = intG
+                pixels[3 * x + 2 + y * bytesPerRow] = intB
+            }
+        }
+
+        let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.none.rawValue)
+
+        guard let provider = CGDataProvider(data: data) else { return nil }
+        guard let cgImage = CGImage(width: width, height: height, bitsPerComponent: 8, bitsPerPixel: 24, bytesPerRow: bytesPerRow,
+        space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: bitmapInfo, provider: provider, decode: nil, shouldInterpolate: true, intent: .defaultIntent) else { return nil }
+
+        self.init(cgImage: cgImage)
+    }
+}
+
+private func decodeDC(_ value: Int) -> (Float, Float, Float) {
+    let intR = value >> 16
+    let intG = (value >> 8) & 255
+    let intB = value & 255
+    return (sRGBToLinear(intR), sRGBToLinear(intG), sRGBToLinear(intB))
+}
+
+private func decodeAC(_ value: Int, maximumValue: Float) -> (Float, Float, Float) {
+	let quantR = value / (19 * 19)
+	let quantG = (value / 19) % 19
+	let quantB = value % 19
+
+	let rgb = (
+		signPow((Float(quantR) - 9) / 9, 2) * maximumValue,
+		signPow((Float(quantG) - 9) / 9, 2) * maximumValue,
+		signPow((Float(quantB) - 9) / 9, 2) * maximumValue
+	)
+
+	return rgb
+}
+
+private func signPow(_ value: Float, _ exp: Float) -> Float {
+    return copysign(pow(abs(value), exp), value)
+}
+
+private func linearTosRGB(_ value: Float) -> Int {
+    let v = max(0, min(1, value))
+    if v <= 0.0031308 { return Int(v * 12.92 * 255 + 0.5) }
+    else { return Int((1.055 * pow(v, 1 / 2.4) - 0.055) * 255 + 0.5) }
+}
+
+private func sRGBToLinear<Type: BinaryInteger>(_ value: Type) -> Float {
+    let v = Float(Int64(value)) / 255
+    if v <= 0.04045 { return v / 12.92 }
+    else { return pow((v + 0.055) / 1.055, 2.4) }
+}
+
+private let encodeCharacters: [String] = {
+    return "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz#$%*+,-.:;=?@[]^_{|}~".map { String($0) }
+}()
+
+private let decodeCharacters: [String: Int] = {
+	var dict: [String: Int] = [:]
+	for (index, character) in encodeCharacters.enumerated() {
+		dict[character] = index
+	}
+	return dict
+}()
+
+extension String {
+	func decode83() -> Int {
+		var value: Int = 0
+		for character in self {
+			if let digit = decodeCharacters[String(character)] {
+				value = value * 83 + digit
+			}
+		}
+		return value
+	}
+}
+
+private extension String {
+	subscript (offset: Int) -> Character {
+		return self[index(startIndex, offsetBy: offset)]
+	}
+
+	subscript (bounds: CountableClosedRange<Int>) -> Substring {
+		let start = index(startIndex, offsetBy: bounds.lowerBound)
+		let end = index(startIndex, offsetBy: bounds.upperBound)
+		return self[start...end]
+	}
+
+	subscript (bounds: CountableRange<Int>) -> Substring {
+		let start = index(startIndex, offsetBy: bounds.lowerBound)
+		let end = index(startIndex, offsetBy: bounds.upperBound)
+		return self[start..<end]
+	}
+}
+
+// swiftlint:enable all

ElementX/Sources/Screens/HomeScreen/HomeScreenModels.swift

@@ -52,7 +52,7 @@ struct HomeScreenViewState: BindableState {
     }
 }
 
-struct HomeScreenRoom: Identifiable {
+struct HomeScreenRoom: Identifiable, Equatable {
     let id: String
     
     var displayName: String?

ElementX/Sources/Screens/HomeScreen/View/HomeScreen.swift

@@ -84,6 +84,7 @@ struct HomeScreen: View {
                         .font(.subheadline)
                         .fontWeight(.bold)
                 }
+                .animation(.easeInOut, value: context.viewState.userAvatar)
             }
             ToolbarItem(placement: .navigationBarTrailing) {
                 Button("Logout") {
@@ -135,6 +136,7 @@ struct RoomCell: View {
                     }
                 }
             }
+            .animation(.easeInOut, value: room)
             .frame(minHeight: 60.0)
             .onAppear {
                 context.send(viewAction: .loadRoomData(roomIdentifier: room.id))

ElementX/Sources/Screens/RoomScreen/View/Timeline/EventBasedTimelineView.swift

@@ -38,6 +38,7 @@ struct EventBasedTimelineView: View {
         }
         .clipShape(Circle())
         .frame(width: 24.0, height: 24.0)
+        .animation(.easeInOut, value: timelineItem.senderAvatar)
     }
     
     private var firstLetter: String {

ElementX/Sources/Screens/RoomScreen/View/Timeline/ImageRoomTimelineView.swift

@@ -13,21 +13,39 @@ struct ImageRoomTimelineView: View {
     let timelineItem: ImageRoomTimelineItem
     
     var body: some View {
-        if let image = timelineItem.image {
+        if timelineItem.image != nil || timelineItem.blurhash != nil { // Fixes view heights after loading finishes
             VStack(alignment: .leading) {
                 EventBasedTimelineView(timelineItem: timelineItem)
                 Text(timelineItem.text)
-                Image(uiImage: image)
+                if let image = timelineItem.image {
-                    .resizable()
+                    if let aspectRatio = timelineItem.aspectRatio {
-                    .scaledToFit()
+                        Image(uiImage: image)
+                            .resizable()
+                            .aspectRatio(aspectRatio, contentMode: .fit)
+                    } else {
+                        Image(uiImage: image)
+                            .resizable()
+                            .scaledToFit()
+                    }
+                } else if let blurhash = timelineItem.blurhash,
+                          // Build a small blurhash image so that it's fast
+                          let image = UIImage(blurHash: blurhash, size: .init(width: 10.0, height: 10.0)) {
+                    Image(uiImage: image)
+                        .resizable()
+                        .aspectRatio(timelineItem.aspectRatio, contentMode: .fit)
+                }
             }
+            .animation(.easeInOut, value: timelineItem.image)
+            .frame(maxHeight: 1000.0)
         } else {
-            VStack(alignment: .center) {
+            VStack(alignment: .leading) {
+                EventBasedTimelineView(timelineItem: timelineItem)
+                Text(timelineItem.text)
                 HStack {
-                    Text(timelineItem.text)
+                    Spacer()
+                    ProgressView("Loading")
                     Spacer()
                 }
-                ProgressView("Loading")
             }
         }
     }
@@ -50,7 +68,7 @@ struct ImageRoomTimelineView_Previews: PreviewProvider {
                                                      url: nil,
                                                      image: UIImage(systemName: "photo"))
             ImageRoomTimelineView(timelineItem: timelineItem)
-            
+
             let timelineItem = ImageRoomTimelineItem(id: UUID().uuidString,
                                                      text: "Some other image",
                                                      timestamp: "Now",
@@ -59,6 +77,17 @@ struct ImageRoomTimelineView_Previews: PreviewProvider {
                                                      url: nil,
                                                      image: nil)
             ImageRoomTimelineView(timelineItem: timelineItem)
+            
+            let timelineItem = ImageRoomTimelineItem(id: UUID().uuidString,
+                                                     text: "Blurhashed image",
+                                                     timestamp: "Now",
+                                                     shouldShowSenderDetails: false,
+                                                     senderId: "Bob",
+                                                     url: nil,
+                                                     image: nil,
+                                                     aspectRatio: 0.7,
+                                                     blurhash: "L%KUc%kqS$RP?Ks,WEf8OlrqaekW")
+            ImageRoomTimelineView(timelineItem: timelineItem)
         }
     }
 }

ElementX/Sources/Services/Room/Messages/ImageRoomMessage.swift

@@ -6,7 +6,7 @@
 //  Copyright © 2022 Element. All rights reserved.
 //
 
-import Foundation
+import UIKit
 import MatrixRustSDK
 
 struct ImageRoomMessage: RoomMessageProtocol {
@@ -35,4 +35,24 @@ struct ImageRoomMessage: RoomMessageProtocol {
     var url: String? {
         message.url()
     }
+    
+    var width: CGFloat? {
+        guard let width = message.width() else {
+            return nil
+        }
+        
+        return CGFloat(width)
+    }
+    
+    var height: CGFloat? {
+        guard let height = message.height() else {
+            return nil
+        }
+        
+        return CGFloat(height)
+    }
+    
+    var blurhash: String? {
+        message.blurhash()
+    }
 }

ElementX/Sources/Services/Timeline/TimelineItems/Items/ImageRoomTimelineItem.swift

@@ -21,4 +21,9 @@ struct ImageRoomTimelineItem: EventBasedTimelineItemProtocol, Identifiable, Equa
     
     let url: String?
     var image: UIImage?
+    
+    var width: CGFloat?
+    var height: CGFloat?
+    var aspectRatio: CGFloat?
+    var blurhash: String?
 }

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItemFactory.swift

@@ -63,6 +63,13 @@ struct RoomTimelineItemFactory {
                                                    _ showSenderDetails: Bool,
                                                    _ displayName: String?,
                                                    _ avatarImage: UIImage?) -> RoomTimelineItemProtocol {
+        
+        var aspectRatio: CGFloat?
+        if let width = message.width,
+           let height = message.height {
+            aspectRatio = width / height
+        }
+        
         return ImageRoomTimelineItem(id: message.id,
                                      text: message.body,
                                      timestamp: message.originServerTs.formatted(date: .omitted, time: .shortened),
@@ -71,7 +78,11 @@ struct RoomTimelineItemFactory {
                                      senderDisplayName: displayName,
                                      senderAvatar: avatarImage,
                                      url: message.url,
-                                     image: mediaProvider.imageForURL(message.url))
+                                     image: mediaProvider.imageForURL(message.url),
+                                     width: message.width,
+                                     height: message.height,
+                                     aspectRatio: aspectRatio,
+                                     blurhash: message.blurhash)
     }
     
     private func buildNoticeTimelineItemFromMessage(_ message: NoticeRoomMessage,