Merge pull request #3 from fummicc1/dev

Update README and Example

Author: fummicc1

Example/Example/ContentView.swift

@@ -27,7 +27,7 @@ struct ContentView: View {
         VStack {
             ScrollView {
                 LazyVGrid(columns: [.init(), .init()]) {
-                    ForEach(0..<1000, id: \.self) { _ in
+                    ForEach(0..<100, id: \.self) { _ in
                         AsyncDownSamplingImage(
                             url: $url,
                             downsampleSize: size
@@ -51,7 +51,7 @@ struct ContentView: View {
         VStack {
             ScrollView {
                 LazyVGrid(columns: [.init(), .init()]) {
-                    ForEach(0..<1000, id: \.self) { _ in
+                    ForEach(0..<100, id: \.self) { _ in
                         AsyncImage(url: url) { phase in
                             switch phase {
                             case .empty:

README.md

@@ -1,3 +1,85 @@
 # AsyncDownSamplingImage
 
-A description of this package.
+`AsyncDownSamplingImage` is a SwiftUI component that has similar interface to original [AsyncImage](https://developer.apple.com/documentation/swiftui/asyncimage) and can perform downsampling so that we can reduce the memory buffer to store image data fetched from a server.
+
+# Impact of Downsampling
+
+with downsampling, we can reduce the huge amount of memory use like the below.
+
+|default AsyncImage| AsyncDownSamplingImage (×2~3 efficient) |
+|---|---|
+|<img width="480" alt="Screenshot 2023-02-03 at 21 58 31" src="https://user-images.githubusercontent.com/44002126/216665559-7f4efbc5-c649-4f25-b9fa-95f5ca60cf67.png">|<img width="480" alt="Screenshot 2023-02-03 at 21 58 48" src="https://user-images.githubusercontent.com/44002126/216665576-f1b994a7-b7ac-49d3-8e44-bda8f1b64130.png">|
+
+
+Moreover, the more the number of images increases, the more we can get the benefit.
+
+Below is a comparision when I scrolled and show 100 high resolution images (1000×1000px).
+
+|default AsyncImage| AsyncDownSamplingImage (×10~ efficient) |
+|---|---|
+|<img width="480" alt="Screenshot 2023-02-04 at 2 11 31" src="https://user-images.githubusercontent.com/44002126/216666328-6d4ea99c-45d4-48d0-960d-b162a9155413.png">|<img width="480" alt="Screenshot 2023-02-04 at 2 12 06" src="https://user-images.githubusercontent.com/44002126/216666337-0e079274-5a55-4469-b9ae-4c4dfc5b838d.png">|
+
+
+
+# How to use AsyncDownSamplingImage
+
+`AsyncDownSamplingImage` aims to be used in a similar way to `AsyncImage` even if the implementation is different.
+
+```swift
+public init(
+  url: Binding<URL?>,
+  downsampleSize: Binding<CGSize>,
+  content: @escaping (Image) -> Content,
+  placeholder: (() -> Placeholder)?,
+  fail: @escaping (Error) -> Fail
+)
+```
+
+```swift
+public init(
+  url: Binding<URL?>,
+  downsampleSize: Binding<CGSize>,
+  content: @escaping (Image) -> Content,
+  fail: @escaping (Error) -> Fail
+)
+```
+
+```swift
+public init(
+  url: Binding<URL?>,
+  downsampleSize: CGSize,
+  content: @escaping (Image) -> Content,
+  fail: @escaping (Error) -> Fail
+)
+```
+
+You can use `AsyncDownSamplingImage` in the following way.
+
+```swift
+
+@State private var url = URL(string: "https://via.placeholder.com/1000")
+@State private var size: CGSize = .init(width: 160, height: 160)
+
+...
+
+AsyncDownSamplingImage(
+  url: $url,
+  downsampleSize: size
+) { image in
+  image
+      .resizable()
+      .frame(width: size.width, height: size.height)
+} fail: { error in
+  Text("Error: \(error.localizedDescription)")
+}
+```
+
+
+
+# Contributing
+
+Pull requests, bug reports and feature requests are welcome 🚀
+
+# License
+
+[MIT LICENSE](https://github.com/fummicc1/AsyncDownSamplingImage/blob/main/LICENSE)