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Color Slider Component (SwiftUI)
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| // A Color Slider that is similar to one in | |
| // iOS 18+ when configuring a tinted Home Screen | |
| // Full video-walktrough on building this component: https://youtu.be/VFVyN5hNW24 | |
| import SwiftUI | |
| fileprivate let SLIDER_HEIGHT = 34.0 | |
| fileprivate let KNOB_DIAMETER = SLIDER_HEIGHT + 4.0 | |
| struct ColorSlider: View { | |
| @Binding var value: Double | |
| let colorList: [Color] | |
| @Environment(\.self) private var environment | |
| @State private var currentOffset = 0.0 | |
| @State private var isDragging: Bool = false | |
| @GestureState private var dragTranslation = 0.0 | |
| var body: some View { | |
| GeometryReader { container in | |
| let sliderWidth = container.size.width - KNOB_DIAMETER | |
| Capsule() | |
| .fill( | |
| LinearGradient( | |
| colors: colorList, | |
| startPoint: .leading, | |
| endPoint: .trailing | |
| ) | |
| ) | |
| .strokeBorder(Color.black.opacity(0.1), lineWidth: 2) | |
| .overlay( | |
| Circle() | |
| .fill(calculateKnobColor(value: value, colorList: colorList)) | |
| .strokeBorder(Color.white, lineWidth: isDragging ? 8 : 5) | |
| .animation(.easeIn(duration: 0.1), value: isDragging) | |
| .frame(height: KNOB_DIAMETER) | |
| .compositingGroup() | |
| .shadow(color: .black.opacity(0.05), radius: 1, x: 0, y: 1) | |
| .shadow(color: .black.opacity(0.05), radius: 2, x: 0, y: 1.5) | |
| .shadow(color: .black.opacity(0.1), radius: 4, x: 0, y: 2) | |
| .offset( | |
| x: clampOffset( | |
| offset: currentOffset + dragTranslation, | |
| sliderWidth: sliderWidth | |
| ) | |
| ) | |
| .gesture( | |
| DragGesture(minimumDistance: 0) | |
| .updating($dragTranslation) { dragValue, state, _ in | |
| isDragging = true | |
| state = dragValue.translation.width | |
| value = convertOffsetToValue( | |
| offset: clampOffset(offset: currentOffset + state, sliderWidth: sliderWidth), | |
| sliderWidth: sliderWidth | |
| ) | |
| } | |
| .onEnded { dragValue in | |
| isDragging = false | |
| currentOffset = clampOffset( | |
| offset: currentOffset + dragValue.translation.width, | |
| sliderWidth: sliderWidth | |
| ) | |
| } | |
| ) | |
| ) | |
| .onAppear { | |
| currentOffset = convertValueToOffset(value: value, sliderWidth: sliderWidth) | |
| } | |
| } | |
| .frame(height: SLIDER_HEIGHT) | |
| } | |
| private func clampOffset(offset: Double, sliderWidth: Double) -> Double { | |
| min(max(offset, -1 * sliderWidth / 2.0), sliderWidth / 2.0) | |
| } | |
| private func convertOffsetToValue(offset: Double, sliderWidth: Double) -> Double { | |
| return (offset / sliderWidth) + 0.5 | |
| } | |
| private func convertValueToOffset(value: Double, sliderWidth: Double) -> Double { | |
| return (value - 0.5) * sliderWidth | |
| } | |
| private func calculateKnobColor(value: Double, colorList: [Color]) -> Color { | |
| let valueIndex = Double(colorList.count - 1) * value | |
| let leadingColorIndex = Int(floor(valueIndex)) | |
| let trailingColorIndex = Int(ceil(valueIndex)) | |
| let proportion = valueIndex - Double(leadingColorIndex) | |
| let resolvedLeadingColor = colorList[leadingColorIndex].resolve(in: environment) | |
| let resolvedTrailingColor = colorList[trailingColorIndex].resolve(in: environment) | |
| return Color( | |
| red: Double(resolvedLeadingColor.red) * (1 - proportion) + Double(resolvedTrailingColor.red) * proportion, | |
| green: Double(resolvedLeadingColor.green) * (1 - proportion) + Double(resolvedTrailingColor.green) * proportion, | |
| blue: Double(resolvedLeadingColor.blue) * (1 - proportion) + Double(resolvedTrailingColor.blue) * proportion | |
| ) | |
| } | |
| } | |
| #Preview { | |
| @Previewable @State var hue: Double = 0.3 | |
| @Previewable @State var lightness: Double = 0.7 | |
| VStack(spacing: 27) { | |
| // Text("\(value)") | |
| ColorSlider( | |
| value: $hue, | |
| colorList: stride(from: 0, through: 1, by: 0.2).map { | |
| Color(hue: $0, saturation: 0.8, brightness: 1) | |
| } | |
| ) | |
| ColorSlider( | |
| value: $lightness, | |
| colorList: [ | |
| Color(hue: hue, saturation: 0.1, brightness: 1), | |
| Color(hue: hue, saturation: 1.0, brightness: 0.7) | |
| ] | |
| ) | |
| } | |
| .padding(.horizontal, 24) | |
| } |
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