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Add value provider for key path property ‘Colors’
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lottie-swift/src/Public/DynamicProperties/ValueProviders/ColorsValueProvider.swift
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,133 @@ | ||
| // | ||
| // ColorsValueProvider.swift | ||
| // lottie-swift | ||
| // | ||
| // Created by Enrique Bermúdez on 10/27/19. | ||
| // | ||
|
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| import Foundation | ||
| import CoreGraphics | ||
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| /// A `ValueProvider` that returns a Gradient Color Value. | ||
| public final class ColorsValueProvider: AnyValueProvider { | ||
|
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| /// Returns a [Color] for a CGFloat(Frame Time). | ||
| public typealias ColorsValueBlock = (CGFloat) -> [Color] | ||
| /// Returns a [Double](Color locations) for a CGFloat(Frame Time). | ||
| public typealias ColorLocationsBlock = (CGFloat) -> [Double] | ||
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| /// The colors values of the provider. | ||
| public var colors: [Color] { | ||
| didSet { | ||
| hasUpdate = true | ||
| } | ||
| } | ||
|
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| /// The color location values of the provider. | ||
| public var locations: [Double] { | ||
| didSet { | ||
| hasUpdate = true | ||
| } | ||
| } | ||
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| /// Initializes with a block provider. | ||
| public init(block: @escaping ColorsValueBlock, | ||
| locations: ColorLocationsBlock? = nil) { | ||
| self.block = block | ||
| self.locationsBlock = locations | ||
| self.colors = [] | ||
| self.locations = [] | ||
| } | ||
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| /// Initializes with an array of colors. | ||
| public init(_ colors: [Color], | ||
| locations: [Double] = []) { | ||
| self.colors = colors | ||
| self.locations = locations | ||
| hasUpdate = true | ||
| } | ||
|
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| // MARK: ValueProvider Protocol | ||
|
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| public var valueType: Any.Type { | ||
| return [Double].self | ||
| } | ||
|
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| public func hasUpdate(frame: CGFloat) -> Bool { | ||
| if block != nil || locationsBlock != nil { | ||
| return true | ||
| } | ||
| return hasUpdate | ||
| } | ||
|
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| public func value(frame: CGFloat) -> Any { | ||
| hasUpdate = false | ||
| let newColors: [Color] | ||
| if let block = block { | ||
| newColors = block(frame) | ||
| } else { | ||
| newColors = colors | ||
| } | ||
|
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| let newLocations: [Double] | ||
| if let colorLocationsBlock = locationsBlock { | ||
| newLocations = colorLocationsBlock(frame) | ||
| } else { | ||
| newLocations = locations | ||
| } | ||
|
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| return self.value(from: newColors, locations: newLocations) | ||
| } | ||
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| // MARK: Private | ||
|
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| func value(from colors: [Color], locations: [Double]) -> [Double] { | ||
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| var colorValues = [Double]() | ||
| var alphaValues = [Double]() | ||
| var shouldAddAlphaValues = false | ||
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| for i in 0..<colors.count { | ||
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| if colors[i].a < 1 { shouldAddAlphaValues = true } | ||
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| let location = locations.count > i ? locations[i] : | ||
| calculateLocation(withStartValue: locations.last ?? 0.0, | ||
| endValue: 1.0, | ||
| elements: colors.count - locations.count, | ||
| position: i - locations.count, | ||
| skipStartValue: locations.count > 0) | ||
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| colorValues.append(location) | ||
| colorValues.append(colors[i].r) | ||
| colorValues.append(colors[i].g) | ||
| colorValues.append(colors[i].b) | ||
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| alphaValues.append(location) | ||
| alphaValues.append(colors[i].a) | ||
| } | ||
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| return colorValues + (shouldAddAlphaValues ? alphaValues : []) | ||
| } | ||
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| private func calculateLocation(withStartValue startValue: Double, | ||
| endValue: Double, | ||
| elements: Int, | ||
| position: Int, | ||
| skipStartValue: Bool) -> Double{ | ||
|
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| guard startValue != endValue else { return 1.0 } | ||
|
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| let strides = (elements - 1) + (skipStartValue ? 1 : 0) | ||
| let index = position + (skipStartValue ? 1 : 0) | ||
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| return Array(stride(from: startValue, | ||
| through: endValue, | ||
| by: (endValue - startValue) / Double(strides)))[index] | ||
| } | ||
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| private var hasUpdate: Bool = true | ||
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| private var block: ColorsValueBlock? | ||
| private var locationsBlock: ColorLocationsBlock? | ||
| } |