From e3392bb948ad53889ad334140952f2acf614668e Mon Sep 17 00:00:00 2001
From: Dustin Mierau <dustin@mierau.me>
Date: Wed, 6 Dec 2023 22:52:09 -0800
Subject: Some work on news. More UI tweaks across the board.

---
 Hotline/Utility/ObservableScrollView.swift | 38 ++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Hotline/Utility/ObservableScrollView.swift

(limited to 'Hotline/Utility/ObservableScrollView.swift')

diff --git a/Hotline/Utility/ObservableScrollView.swift b/Hotline/Utility/ObservableScrollView.swift
new file mode 100644
index 0000000..a6f46cc
--- /dev/null
+++ b/Hotline/Utility/ObservableScrollView.swift
@@ -0,0 +1,38 @@
+import SwiftUI
+
+struct ScrollViewOffsetPreferenceKey: PreferenceKey {
+  typealias Value = CGFloat
+  static var defaultValue = CGFloat.zero
+  static func reduce(value: inout Value, nextValue: () -> Value) {
+    value += nextValue()
+  }
+}
+
+struct ObservableScrollView<Content>: View where Content : View {
+  @Namespace var scrollSpace
+  @Binding var scrollOffset: CGFloat
+  let content: () -> Content
+  
+  init(scrollOffset: Binding<CGFloat>,
+       @ViewBuilder content: @escaping () -> Content) {
+    _scrollOffset = scrollOffset
+    self.content = content
+  }
+  
+  var body: some View {
+    ScrollView {
+      content()
+        .background(GeometryReader { geo in
+          let offset = -geo.frame(in: .named(scrollSpace)).minY
+          Color.clear
+            .preference(key: ScrollViewOffsetPreferenceKey.self,
+                        value: offset)
+        })
+      
+    }
+    .coordinateSpace(name: scrollSpace)
+    .onPreferenceChange(ScrollViewOffsetPreferenceKey.self) { value in
+      scrollOffset = value
+    }
+  }
+}
-- 
cgit