Leif/p 12 allow customized content

Sources/Picture/Internal/MultipleImageView.swift

@@ -0,0 +1,106 @@
+import SwiftUI
+
+// TODO: [P-9](https://github.com/0xOpenBytes/Picture/issues/9)
+public struct MultipleImageView: View {
+    let images: [Image]
+
+    public var body: some View {
+        switch images.count {
+        case 0:     placeholderView
+        case 1:     SingleImageView(image: images[0])
+        case 2:     doubleImageView
+        case 3:     tripleImageView
+        default:    fallbackImageView
+
+        }
+    }
+
+    private var placeholderView: some View {
+        Image(systemName: "photo.artframe")
+            .resizable()
+            .aspectRatio(contentMode: .fit)
+    }
+
+    private var doubleImageView: some View {
+            VStack {
+                images[0]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+                images[1]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+            }
+    }
+
+    private var tripleImageView: some View {
+        HStack {
+            images[0]
+                .resizable()
+                .aspectRatio(contentMode: .fit)
+            VStack {
+                images[1]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+
+                images[2]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+            }
+        }
+    }
+
+    private var fallbackImageView: some View {
+        Grid {
+            GridRow {
+                images[0]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+                images[1]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+            }
+            GridRow {
+                images[2]
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+                Image(systemName: "ellipsis")
+                    .resizable()
+                    .aspectRatio(contentMode: .fit)
+            }
+        }
+    }
+}
+
+struct MultipleImageView_Preview: PreviewProvider {
+    static var previews: some View {
+        MultipleImageView(
+            images: [
+                Image(systemName: "photo.artframe")
+            ]
+        )
+
+        MultipleImageView(
+            images: [
+                Image(systemName: "photo.artframe"),
+                Image(systemName: "photo.artframe")
+            ]
+        )
+
+        MultipleImageView(
+            images: [
+                Image(systemName: "photo.artframe"),
+                Image(systemName: "photo.artframe"),
+                Image(systemName: "photo.artframe")
+            ]
+        )
+
+        MultipleImageView(
+            images: [
+                Image(systemName: "photo.artframe"),
+                Image(systemName: "photo.artframe"),
+                Image(systemName: "photo.artframe"),
+                Image(systemName: "photo.artframe")
+            ]
+        )
+    }
+}

Sources/Picture/Internal/PictureViewModel.swift

@@ -0,0 +1,40 @@
+import OSLog
+import SwiftUI
+
+class PictureViewModel: ObservableObject {
+    private let logger = Logger(subsystem: "PictureViewModel", category: "VM")
+    private var task: Task<Void, Never>?
+
+    let sources: [PictureSource]
+
+    @Published var images: [Image]
+
+    init(sources: [PictureSource]) {
+        self.sources = sources
+        self.task = nil
+        self.images = []
+    }
+
+    deinit {
+        task?.cancel()
+    }
+
+    @MainActor
+    func load() {
+        task?.cancel()
+
+        task = Task {
+            for source in sources.prefix(5) {
+                do {
+                    if let loadedImage = try await source.load() {
+                        DispatchQueue.main.async { [weak self] in
+                            self?.images.append(loadedImage)
+                        }
+                    }
+                } catch {
+                    logger.error("\(error.localizedDescription)")
+                }
+            }
+        }
+    }
+}

Sources/Picture/Internal/SingleImageView.swift

@@ -0,0 +1,16 @@
+import SwiftUI
+
+// TODO: [P-8](https://github.com/0xOpenBytes/Picture/issues/8)
+public struct SingleImageView: View {
+    let image: Image
+
+    public var body: some View {
+        image
+    }
+}
+
+struct SingleImageView_Preview: PreviewProvider {
+    static var previews: some View {
+        SingleImageView(image: Image(systemName: "photo.artframe"))
+    }
+}

Sources/Picture/Public/Picture+init.swift

@@ -1,19 +1,103 @@
 import SwiftUI
 
-extension Picture {
+// MARK: - Default Implementation
+
+extension Picture
+where SingleImageContent == SingleImageView,
+      MultipleImageContent == MultipleImageView
+{
+
+    public init(
+        sources: [PictureSource]
+    ) {
+        self.init(
+            sources: sources,
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: MultipleImageContent.init
+        )
+    }
+
     public init(image: Image) {
-        self.init(sources: [.local(image)])
+        self.init(
+            sources: [.local(image)],
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: MultipleImageContent.init
+        )
     }
 
     public init(url: URL) {
-        self.init(sources: [.remote(url)])
+        self.init(
+            sources: [.remote(url)],
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: MultipleImageContent.init
+        )
     }
-    
+
     public init(images: [Image]) {
-        self.init(sources: images.map(PictureSource.local))
+        self.init(
+            sources: images.map(PictureSource.local),
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: MultipleImageContent.init
+        )
     }
 
     public init(urls: [URL]) {
-        self.init(sources: urls.map(PictureSource.remote))
+        self.init(
+            sources: urls.map(PictureSource.remote),
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: MultipleImageContent.init
+        )
+    }
+}
+
+// MARK: - Single Image Initialization
+
+extension Picture where MultipleImageContent == MultipleImageView {
+    public init(
+        image: Image,
+        @ViewBuilder singleImageContent: @escaping (Image) -> SingleImageContent
+    ) {
+        self.init(
+            sources: [.local(image)],
+            singleImageContent: singleImageContent,
+            multipleImageContent: MultipleImageContent.init
+        )
+    }
+
+    public init(
+        url: URL,
+        @ViewBuilder singleImageContent: @escaping (Image) -> SingleImageContent
+    ) {
+        self.init(
+            sources: [.remote(url)],
+            singleImageContent: singleImageContent,
+            multipleImageContent: MultipleImageContent.init
+        )
+    }
+}
+
+// MARK: - Multiple Image Initialization
+
+extension Picture where SingleImageContent == SingleImageView {
+    public init(
+        images: [Image],
+        @ViewBuilder multipleImageContent: @escaping ([Image]) -> MultipleImageContent
+    ) {
+        self.init(
+            sources: images.map(PictureSource.local),
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: multipleImageContent
+        )
+    }
+
+    public init(
+        urls: [URL],
+        @ViewBuilder multipleImageContent: @escaping ([Image]) -> MultipleImageContent
+    ) {
+        self.init(
+            sources: urls.map(PictureSource.remote),
+            singleImageContent: SingleImageView.init,
+            multipleImageContent: multipleImageContent
+        )
     }
 }

Sources/Picture/Public/Picture.swift

@@ -1,14 +1,28 @@
 import SwiftUI
 
-public struct Picture: View {
+public struct Picture<
+    SingleImageContent: View,
+    MultipleImageContent: View
+>: View {
     private let sources: [PictureSource]
+    private let singleImageContent: (Image) -> SingleImageContent
+    private let multipleImageContent: ([Image]) -> MultipleImageContent
 
+
+    @ObservedObject private var viewModel: PictureViewModel
     @State private var isFullscreen: Bool = false
     @State private var isViewingImage: Bool = false
     @State private var currentSourceIndex: Int = 0
 
-    public init(sources: [PictureSource]) {
+    public init(
+        sources: [PictureSource],
+        @ViewBuilder singleImageContent: @escaping (Image) -> SingleImageContent,
+        @ViewBuilder multipleImageContent: @escaping ([Image]) -> MultipleImageContent
+    ) {
+        self._viewModel = ObservedObject(initialValue: PictureViewModel(sources: sources))
         self.sources = sources
+        self.singleImageContent = singleImageContent
+        self.multipleImageContent = multipleImageContent
     }
 
     @ViewBuilder
@@ -70,10 +84,14 @@ public struct Picture: View {
 
     public var body: some View {
         Group {
-            if sources.count == 1 {
-                Text("Image")
-            } else {
-                Text("Images: \(sources.count)")
+            switch viewModel.images.count {
+            case 0:
+                ProgressView()
+                    .onAppear {
+                        viewModel.load()
+                    }
+            case 1:     singleImageBody
+            default:    multipleImageBody
             }
         }
         .sheet(isPresented: $isFullscreen) {
@@ -83,6 +101,18 @@ public struct Picture: View {
             isFullscreen = true
         }
     }
+
+    @ViewBuilder
+    private var singleImageBody: some View {
+        if let image = viewModel.images.first {
+            singleImageContent(image)
+        }
+    }
+
+    @ViewBuilder
+    private var multipleImageBody: some View {
+        multipleImageContent(viewModel.images)
+    }
 }
 
 struct Picture_Preview: PreviewProvider {

Sources/Picture/Public/PictureSourceImage.swift

@@ -0,0 +1,32 @@
+import SwiftUI
+
+public struct PictureSourceImage: View {
+    @ObservedObject private var viewModel: InteractableImageViewModel
+
+    public init(
+        source: PictureSource
+    ) {
+        self._viewModel = ObservedObject(
+            initialValue: InteractableImageViewModel(source: source)
+        )
+    }
+
+    public var body: some View {
+        if let image = viewModel.image {
+            image
+                .resizable()
+                .aspectRatio(contentMode: .fit)
+        } else {
+            ProgressView()
+                .onAppear {
+                    viewModel.load()
+                }
+        }
+    }
+}
+
+struct PictureSourceImage_Preview: PreviewProvider {
+    static var previews: some View {
+        PictureSourceImage(source: .local(Image(systemName: "photo.artframe")))
+    }
+}