Add gestureMinimumDistance argument to allow customizing the gesture sensitivity

Package.swift

@@ -6,7 +6,8 @@ let package = Package(
     name: "SwiftUIPageView",
     platforms: [
         .iOS(.v14),
-        .watchOS(.v7)
+        .watchOS(.v7),
+        .macOS(.v11),
     ],
     products: [
         .library(

README.md

@@ -19,6 +19,7 @@ HPageView(alignment: .leading, pageWidth: 250, spacing: 12) {
 * `pageWidth`: The width of each page, or `nil` if you want each page to fill the width of the page view.
 * `spacing`: The distance between adjacent pages, or `nil` if you want the page view to choose a default distance for each pair of pages.
 * `content`: A view builder that creates the content of this page view.
+* `index`: An `Int` binding that exposes active page
 
 ## VPageView
 A view that arranges its children in a vertical line, and provides paged scrolling behaviour.
@@ -35,6 +36,7 @@ VPageView(alignment: .top, pageHeight: 250, spacing: 12) {
 * `pageHeight`: The height of each page, or `nil` if you want each page to fill the height of the page view.
 * `spacing`: The distance between adjacent pages, or `nil` if you want the page view to choose a default distance for each pair of pages.
 * `content`: A view builder that creates the content of this page view.
+* `index`: An `Int` binding that exposes active page
 
 ## PageView
 A view that arranges its children in a line, and provides paged scrolling behaviour.
@@ -54,6 +56,35 @@ PageView(.horizontal, alignment: .leading, pageLength: 250, spacing: 12) {
 * `pageLength`: The length of each page, parallel to the layout axis, or `nil` if you want each page to fill the length of the page view.
 * `spacing`: The distance between adjacent pages, or `nil` if you want the page view to choose a default distance for each pair of pages.
 * `content`: A view builder that creates the content of this page view.
+* `index`: An `Int` binding that exposes active page
+
+## Index binding example
+```
+@State var currentIndex: Int = 0
+
+...
+
+/// inside `body`:
+ZStack(alignment: .bottom) {
+	HPageView(alignment: .leading, pageWidth: 250, spacing: 12, index: $currentIndex) {
+		ForEach(items, id: \.id) { item in
+			ItemView(item: item)
+			.padding(.bottom, 24)
+		}
+	}
+
+	/// Indicator dots
+	HStack(spacing: 8) {
+		ForEach(items.indices, id: \.self) { index in
+			Circle()
+				.fill(currentIndex == index ? Color.primary : Color.secondary)
+				.frame(width: 8, height: 8)
+				.animation(.spring(), value: currentIndex == index)
+		}
+	}
+	.padding(.bottom, 8)
+}
+```
 
 ## PageViewReader
 A view that provides programmatic paging, by working with a proxy to move to child pages.

Sources/SwiftUIPageView/API/GestureMinimumDistance.swift

@@ -0,0 +1,27 @@
+//
+//  File.swift
+//  
+//
+//  Created by Tomas Kafka on 27.06.2022.
+//
+
+import Foundation
+import CoreGraphics
+
+public enum GestureMinimumDistance {
+    /// old default
+    case compatible
+    case comfortable
+    case custom(CGFloat)
+
+    var value: CGFloat {
+        switch self {
+        case .compatible:
+            return 15
+        case .comfortable:
+            return 31
+        case .custom(let customDistance):
+            return customDistance
+        }
+    }
+}

Sources/SwiftUIPageView/API/HPageView.swift

@@ -29,12 +29,16 @@ where Content : View
     public init(alignment: PageAlignment<HorizontalPageAlignment, VerticalAlignment> = .center,
                 pageWidth: CGFloat? = nil,
                 spacing: CGFloat? = nil,
+                gestureMinimumDistance: GestureMinimumDistance = .compatible,
+                index: Binding<Int> = Binding.constant(0),
                 @ViewBuilder content: @escaping () -> Content)
     {
         body = PageView(alignment: alignment.alignment,
                         axis: .horizontal,
                         content: content,
                         pageLength: pageWidth,
-                        spacing: spacing)
+                        spacing: spacing,
+						gestureMinimumDistance: gestureMinimumDistance,
+                        index: index)
     }
 }

Sources/SwiftUIPageView/API/PageView.swift

@@ -26,7 +26,9 @@ where Content : View
                             content: content,
                             pageLength: pageLength,
                             spacing: spacing,
-                            viewLength: viewLength)
+                            gestureMinimumDistance: gestureMinimumDistance,
+                            viewLength: viewLength,
+                            index: $index)
         }
         .animation(nil, value: axis)
     }
@@ -36,6 +38,8 @@ where Content : View
     internal var content: () -> Content
     internal var pageLength: CGFloat?
     internal var spacing: CGFloat?
+    internal var gestureMinimumDistance: GestureMinimumDistance
+    @Binding var index: Int
 }
 
 
@@ -62,12 +66,16 @@ public extension PageView {
          alignment: PageAlignment<HorizontalPageAlignment, VerticalPageAlignment> = .center,
          pageLength: CGFloat? = nil,
          spacing: CGFloat? = nil,
+         gestureMinimumDistance: GestureMinimumDistance,
+         index: Binding<Int> = Binding.constant(0),
          @ViewBuilder content: @escaping () -> Content)
     {
         self.alignment = alignment.alignment
         self.axis = axis
         self.content = content
         self.pageLength = pageLength
         self.spacing = spacing
+        self.gestureMinimumDistance = gestureMinimumDistance
+        self._index = index
     }
 }

Sources/SwiftUIPageView/API/VPageView.swift

@@ -29,12 +29,16 @@ where Content : View
     public init(alignment: PageAlignment<HorizontalAlignment, VerticalPageAlignment> = .center,
                 pageHeight: CGFloat? = nil,
                 spacing: CGFloat? = nil,
+                index: Binding<Int> = Binding.constant(0),
+                gestureMinimumDistance: GestureMinimumDistance = .compatible,
                 @ViewBuilder content: @escaping () -> Content)
     {
         body = PageView(alignment: alignment.alignment,
                         axis: .vertical,
                         content: content,
                         pageLength: pageHeight,
-                        spacing: spacing)
+                        spacing: spacing,
+                        gestureMinimumDistance: gestureMinimumDistance,
+                        index: index)
     }
 }

Sources/SwiftUIPageView/Internal/PageGestureView.swift

@@ -20,7 +20,9 @@ where Content : View
     var content: () -> Content
     var pageLength: CGFloat
     var spacing: CGFloat
+    var gestureMinimumDistance: GestureMinimumDistance
     var viewLength: CGFloat
+    @Binding var index: Int
 
     var body: some View {
         PageLayoutView(alignment: alignment,
@@ -55,7 +57,7 @@ where Content : View
         let minimumDistance: CGFloat
 
         switch pageState.dragState {
-        case .dragging, .nearlyEnded, .ended: minimumDistance = 15
+        case .dragging, .nearlyEnded, .ended: minimumDistance = gestureMinimumDistance.value
         case .ending: minimumDistance = 0
         }
 
@@ -100,6 +102,19 @@ where Content : View
     private func offsetToIndex(_ offset: CGFloat) -> CGFloat {
         -offset / (pageLength + spacing)
     }
+
+    private func intFromIndex(_ index: CGFloat) -> Int {
+        if index == .infinity {
+            return pageState.viewCount - 1
+        } else if index == -.infinity {
+            return 0
+        } else if index.isNaN {
+            return 0
+        } else {
+            return Int(round(index))
+        }
+    }
+
     private func onDragChanged(value: DragGesture.Value) {
         if let initialIndex = pageState.initialIndex {
             onDragUpdated(value: value, initialIndex: initialIndex)
@@ -131,6 +146,7 @@ where Content : View
             withAnimation(animationState.dragAnimation) {
                 pageState.index = newIndex
                 pageState.indexOffset = 0
+                self.index = intFromIndex(newIndex)
             }
         }
     }
@@ -167,6 +183,7 @@ where Content : View
         withAnimation(animationState.dragAnimation) {
             pageState.index = newIndex
             pageState.indexOffset = 0
+            self.index = intFromIndex(newIndex)
         }
     }
     private func onDragStarted(value: DragGesture.Value) {
@@ -201,6 +218,7 @@ where Content : View
         withAnimation(animationState.dragAnimation) {
             pageState.index = offsetToIndex(offset)
             pageState.indexOffset = offsetToIndex(additionalOffset - initialOffset)
+            self.index = intFromIndex(offsetToIndex(offset))
         }
     }
     private func onDragUpdated(value: DragGesture.Value, initialIndex: CGFloat) {
@@ -229,5 +247,6 @@ where Content : View
         pageState.dragState = distance == 0 ? .ended : .ending
         pageState.index = newIndex
         pageState.indexOffset = 0
+        self.index = intFromIndex(newIndex)
     }
 }