From f6195f39c8f5cf31315f085f3c571c60f1eb4fb1 Mon Sep 17 00:00:00 2001
From: tomosaaan <tom_aaa_0905@yahoo.co.jp>
Date: Fri, 25 Oct 2024 18:53:39 +0900
Subject: [PATCH] feat: follow selected position to latest drag position

---
 Example/Example/ContentView.swift               | 10 +---------
 .../GraphRangeSlider/Extensions/Array+.swift    |  7 +++++++
 Sources/GraphRangeSlider/GraphRangeSlider.swift |  2 +-
 Sources/GraphRangeSlider/Slider.swift           |  2 +-
 Sources/GraphRangeSlider/SliderToggle.swift     | 17 +++++------------
 5 files changed, 15 insertions(+), 23 deletions(-)
 create mode 100644 Sources/GraphRangeSlider/Extensions/Array+.swift

diff --git a/Example/Example/ContentView.swift b/Example/Example/ContentView.swift
index df8ff7c..3b706fc 100644
--- a/Example/Example/ContentView.swift
+++ b/Example/Example/ContentView.swift
@@ -7,15 +7,7 @@ struct Element: GraphRangeElement {
 }
 
 struct ContentView: View {
-    let data: [Element] = [
-        .init(x: 10, y: 10),
-        .init(x: 20, y: 20),
-        .init(x: 30, y: 30),
-        .init(x: 40, y: 40),
-        .init(x: 50, y: 50),
-        .init(x: 60, y: 60),
-        .init(x: 70, y: 70),
-    ]
+    let data: [Element] = (1...50).map { .init(x: $0 * 10, y: $0 * 10) }
 
     @State var selectedData = [Element]()
 
diff --git a/Sources/GraphRangeSlider/Extensions/Array+.swift b/Sources/GraphRangeSlider/Extensions/Array+.swift
new file mode 100644
index 0000000..6fb66e2
--- /dev/null
+++ b/Sources/GraphRangeSlider/Extensions/Array+.swift
@@ -0,0 +1,7 @@
+import Foundation
+
+extension Array where Element: Comparable {
+    func argmin() -> Index? {
+        indices.min(by: { self[$0] < self[$1] })
+    }
+}
diff --git a/Sources/GraphRangeSlider/GraphRangeSlider.swift b/Sources/GraphRangeSlider/GraphRangeSlider.swift
index aebe958..3d26e21 100644
--- a/Sources/GraphRangeSlider/GraphRangeSlider.swift
+++ b/Sources/GraphRangeSlider/GraphRangeSlider.swift
@@ -15,7 +15,7 @@ public struct GraphRangeSlider<Data, ID>: View where Data: RandomAccessCollectio
     @Binding private var selectedData: Data
     @State private var leftCurrentIndex = 0
     @State private var rightCurrentIndex = 0
-    @State private var positions = [CGFloat]()
+    @State private var positions = ContiguousArray<CGFloat>()
     @Environment(\.graphBarWidth) private var graphBarWidth: CGFloat
     @Environment(\.activeColor) private var activeColor: Color
     @Environment(\.inactiveColor) private var inactiveColor: Color
diff --git a/Sources/GraphRangeSlider/Slider.swift b/Sources/GraphRangeSlider/Slider.swift
index f360268..538b3d7 100644
--- a/Sources/GraphRangeSlider/Slider.swift
+++ b/Sources/GraphRangeSlider/Slider.swift
@@ -1,7 +1,7 @@
 import SwiftUI
 
 struct Slider: View {
-    let positions: [CGFloat]
+    let positions: ContiguousArray<CGFloat>
     @Binding var leftCurrentIndex: Int
     @Binding var rightCurrentIndex: Int
     @State private var viewSize = CGSize.zero
diff --git a/Sources/GraphRangeSlider/SliderToggle.swift b/Sources/GraphRangeSlider/SliderToggle.swift
index 8485fa9..af20431 100644
--- a/Sources/GraphRangeSlider/SliderToggle.swift
+++ b/Sources/GraphRangeSlider/SliderToggle.swift
@@ -5,7 +5,7 @@ struct SliderToggle: View {
         case left, right
     }
 
-    let togglePositions: [CGFloat]
+    let togglePositions: ContiguousArray<CGFloat>
     let limitIndex: Int
     @Binding var currentIndex: Int
     @Environment(\.activeColor) private var activeColor: Color
@@ -31,23 +31,16 @@ struct SliderToggle: View {
             .gesture(
                 DragGesture()
                     .onChanged { value in
-                        let nextIndex = min(currentIndex + 1, togglePositions.endIndex - 1)
-                        let previousIndex = max(currentIndex - 1, 0)
-
                         switch position {
                         case .left:
                             let locationX = value.location.x - toggleRadius
-                            if togglePositions[nextIndex] < locationX {
-                                currentIndex = min(nextIndex, limitIndex - 1)
-                            } else if locationX < togglePositions[previousIndex] {
-                                currentIndex = previousIndex
+                            if let index = togglePositions.map { abs($0 - locationX) }.argmin() {
+                                currentIndex = min(index, limitIndex - 1)
                             }
                         case .right:
                             let locationX = value.location.x + toggleRadius * 3
-                            if togglePositions[nextIndex] < locationX {
-                                currentIndex = nextIndex
-                            } else if locationX < togglePositions[previousIndex] {
-                                currentIndex = max(previousIndex, limitIndex + 1)
+                            if let index = togglePositions.map { abs($0 - locationX) }.argmin() {
+                                currentIndex = max(index, limitIndex + 1)
                             }
                         }
                     }