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//

//  ImageFilter.swift

//

//  Copyright (c) 2015 Alamofire Software Foundation (http://alamofire.org/)

//

//  Permission is hereby granted, free of charge, to any person obtaining a copy

//  of this software and associated documentation files (the "Software"), to deal

//  in the Software without restriction, including without limitation the rights

//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

//  copies of the Software, and to permit persons to whom the Software is

//  furnished to do so, subject to the following conditions:

//

//  The above copyright notice and this permission notice shall be included in

//  all copies or substantial portions of the Software.

//

//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

//  THE SOFTWARE.

//

import Foundation

#if os(iOS) || os(tvOS) || os(watchOS)

import UIKit

#elseif os(macOS)

import Cocoa

#endif

// MARK: ImageFilter

/// The `ImageFilter` protocol defines properties for filtering an image as well as identification of the filter.

public protocol ImageFilter {

    /// A closure used to create an alternative representation of the given image.

    var filter: (Image) -> Image { get }

    /// The string used to uniquely identify the filter operation.

    var identifier: String { get }

}

extension ImageFilter {

    /// The unique identifier for any `ImageFilter` type.

    public var identifier: String { "\(type(of: self))" }

}

// MARK: - Sizable

/// The `Sizable` protocol defines a size property intended for use with `ImageFilter` types.

public protocol Sizable {

    /// The size of the type.

    var size: CGSize { get }

}

extension ImageFilter where Self: Sizable {

    /// The unique idenitifier for an `ImageFilter` conforming to the `Sizable` protocol.

    public var identifier: String {

        let width = Int64(size.width.rounded())

        let height = Int64(size.height.rounded())

        return "\(type(of: self))-size:(\(width)x\(height))"

    }

}

// MARK: - Roundable

/// The `Roundable` protocol defines a radius property intended for use with `ImageFilter` types.

public protocol Roundable {

    /// The radius of the type.

    var radius: CGFloat { get }

}

extension ImageFilter where Self: Roundable {

    /// The unique idenitifier for an `ImageFilter` conforming to the `Roundable` protocol.

    public var identifier: String {

        let radius = Int64(self.radius.rounded())

        return "\(type(of: self))-radius:(\(radius))"

    }

}

// MARK: - DynamicImageFilter

/// The `DynamicImageFilter` class simplifies custom image filter creation by using a trailing closure initializer.

public struct DynamicImageFilter: ImageFilter {

    /// The string used to uniquely identify the image filter operation.

    public let identifier: String

    /// A closure used to create an alternative representation of the given image.

    public let filter: (Image) -> Image

    /// Initializes the `DynamicImageFilter` instance with the specified identifier and filter closure.

    ///

    /// - parameter identifier: The unique identifier of the filter.

    /// - parameter filter:     A closure used to create an alternative representation of the given image.

    ///

    /// - returns: The new `DynamicImageFilter` instance.

    public init(_ identifier: String, filter: @escaping (Image) -> Image) {

        self.identifier = identifier

        self.filter = filter

    }

}

// MARK: - CompositeImageFilter

/// The `CompositeImageFilter` protocol defines an additional `filters` property to support multiple composite filters.

public protocol CompositeImageFilter: ImageFilter {

    /// The image filters to apply to the image in sequential order.

    var filters: [ImageFilter] { get }

}

extension CompositeImageFilter {

    /// The unique idenitifier for any `CompositeImageFilter` type.

    public var identifier: String {

        filters.map { $0.identifier }.joined(separator: "_")

    }

    /// The filter closure for any `CompositeImageFilter` type.

    public var filter: (Image) -> Image {

        { image in

            self.filters.reduce(image) { $1.filter($0) }

        }

    }

}

// MARK: - DynamicCompositeImageFilter

/// The `DynamicCompositeImageFilter` class is a composite image filter based on a specified array of filters.

public struct DynamicCompositeImageFilter: CompositeImageFilter {

    /// The image filters to apply to the image in sequential order.

    public let filters: [ImageFilter]

    /// Initializes the `DynamicCompositeImageFilter` instance with the given filters.

    ///

    /// - parameter filters: The filters taking part in the composite image filter.

    ///

    /// - returns: The new `DynamicCompositeImageFilter` instance.

    public init(_ filters: [ImageFilter]) {

        self.filters = filters

    }

    /// Initializes the `DynamicCompositeImageFilter` instance with the given filters.

    ///

    /// - parameter filters: The filters taking part in the composite image filter.

    ///

    /// - returns: The new `DynamicCompositeImageFilter` instance.

    public init(_ filters: ImageFilter...) {

        self.init(filters)

    }

}

#if os(iOS) || os(tvOS) || os(watchOS)

// MARK: - Single Pass Image Filters (iOS, tvOS and watchOS only) -

/// Scales an image to a specified size.

public struct ScaledToSizeFilter: ImageFilter, Sizable {

    /// The size of the filter.

    public let size: CGSize

    /// Initializes the `ScaledToSizeFilter` instance with the given size.

    ///

    /// - parameter size: The size.

    ///

    /// - returns: The new `ScaledToSizeFilter` instance.

    public init(size: CGSize) {

        self.size = size

    }

    /// The filter closure used to create the modified representation of the given image.

    public var filter: (Image) -> Image {

        { image in

            image.af.imageScaled(to: self.size)

        }

    }

}

// MARK: -

/// Scales an image from the center while maintaining the aspect ratio to fit within a specified size.

public struct AspectScaledToFitSizeFilter: ImageFilter, Sizable {

    /// The size of the filter.

    public let size: CGSize

    /// Initializes the `AspectScaledToFitSizeFilter` instance with the given size.

    ///

    /// - parameter size: The size.

    ///

    /// - returns: The new `AspectScaledToFitSizeFilter` instance.

    public init(size: CGSize) {

        self.size = size

    }

    /// The filter closure used to create the modified representation of the given image.

    public var filter: (Image) -> Image {

        { image in

            image.af.imageAspectScaled(toFit: self.size)

        }

    }

}

// MARK: -

/// Scales an image from the center while maintaining the aspect ratio to fill a specified size. Any pixels that fall

/// outside the specified size are clipped.

public struct AspectScaledToFillSizeFilter: ImageFilter, Sizable {

    /// The size of the filter.

    public let size: CGSize

    /// Initializes the `AspectScaledToFillSizeFilter` instance with the given size.

    ///

    /// - parameter size: The size.

    ///

    /// - returns: The new `AspectScaledToFillSizeFilter` instance.

    public init(size: CGSize) {

        self.size = size

    }

    /// The filter closure used to create the modified representation of the given image.

    public var filter: (Image) -> Image {

        { image in

            image.af.imageAspectScaled(toFill: self.size)

        }

    }

}

// MARK: -

/// Rounds the corners of an image to the specified radius.

public struct RoundedCornersFilter: ImageFilter, Roundable {

    /// The radius of the filter.

    public let radius: CGFloat

    /// Whether to divide the radius by the image scale.

    public let divideRadiusByImageScale: Bool

    /// Initializes the `RoundedCornersFilter` instance with the given radius.

    ///

    /// - parameter radius:                   The radius.

    /// - parameter divideRadiusByImageScale: Whether to divide the radius by the image scale. Set to `true` when the

    ///                                       image has the same resolution for all screen scales such as @1x, @2x and

    ///                                       @3x (i.e. single image from web server). Set to `false` for images loaded

    ///                                       from an asset catalog with varying resolutions for each screen scale.

    ///                                       `false` by default.

    ///

    /// - returns: The new `RoundedCornersFilter` instance.

    public init(radius: CGFloat, divideRadiusByImageScale: Bool = false) {

        self.radius = radius

        self.divideRadiusByImageScale = divideRadiusByImageScale

    }

    /// The filter closure used to create the modified representation of the given image.

    public var filter: (Image) -> Image {

        { image in

            image.af.imageRounded(withCornerRadius: self.radius,

                                  divideRadiusByImageScale: self.divideRadiusByImageScale)

        }

    }

    /// The unique idenitifier for an `ImageFilter` conforming to the `Roundable` protocol.

    public var identifier: String {

        let radius = Int64(self.radius.rounded())

        return "\(type(of: self))-radius:(\(radius))-divided:(\(divideRadiusByImageScale))"

    }

}

// MARK: -

/// Rounds the corners of an image into a circle.

public struct CircleFilter: ImageFilter {

    /// Initializes the `CircleFilter` instance.

    ///

    /// - returns: The new `CircleFilter` instance.

    public init() {}

    /// The filter closure used to create the modified representation of the given image.

    public var filter: (Image) -> Image {

        { image in

            image.af.imageRoundedIntoCircle()

        }

    }

}

// MARK: -

#if os(iOS) || os(tvOS)

/// The `CoreImageFilter` protocol defines `parameters`, `filterName` properties used by CoreImage.

public protocol CoreImageFilter: ImageFilter {

    /// The filter name of the CoreImage filter.

    var filterName: String { get }

    /// The image filter parameters passed to CoreImage.

    var parameters: [String: Any] { get }

}

extension ImageFilter where Self: CoreImageFilter {

    /// The filter closure used to create the modified representation of the given image.

    public var filter: (Image) -> Image {

        { image in

            image.af.imageFiltered(withCoreImageFilter: self.filterName, parameters: self.parameters) ?? image

        }

    }

    /// The unique idenitifier for an `ImageFilter` conforming to the `CoreImageFilter` protocol.

    public var identifier: String { "\(type(of: self))-parameters:(\(parameters))" }

}

/// Blurs an image using a `CIGaussianBlur` filter with the specified blur radius.

public struct BlurFilter: ImageFilter, CoreImageFilter {

    /// The filter name.

    public let filterName = "CIGaussianBlur"

    /// The image filter parameters passed to CoreImage.

    public let parameters: [String: Any]

    /// Initializes the `BlurFilter` instance with the given blur radius.

    ///

    /// - parameter blurRadius: The blur radius.

    ///

    /// - returns: The new `BlurFilter` instance.

    public init(blurRadius: UInt = 10) {

        parameters = ["inputRadius": blurRadius]

    }

}

#endif

// MARK: - Composite Image Filters (iOS, tvOS and watchOS only) -

/// Scales an image to a specified size, then rounds the corners to the specified radius.

public struct ScaledToSizeWithRoundedCornersFilter: CompositeImageFilter {

    /// Initializes the `ScaledToSizeWithRoundedCornersFilter` instance with the given size and radius.

    ///

    /// - parameter size:                     The size.

    /// - parameter radius:                   The radius.

    /// - parameter divideRadiusByImageScale: Whether to divide the radius by the image scale. Set to `true` when the

    ///                                       image has the same resolution for all screen scales such as @1x, @2x and

    ///                                       @3x (i.e. single image from web server). Set to `false` for images loaded

    ///                                       from an asset catalog with varying resolutions for each screen scale.

    ///                                       `false` by default.

    ///

    /// - returns: The new `ScaledToSizeWithRoundedCornersFilter` instance.

    public init(size: CGSize, radius: CGFloat, divideRadiusByImageScale: Bool = false) {

        filters = [ScaledToSizeFilter(size: size),

                   RoundedCornersFilter(radius: radius, divideRadiusByImageScale: divideRadiusByImageScale)]

    }

    /// The image filters to apply to the image in sequential order.

    public let filters: [ImageFilter]

}

// MARK: -

/// Scales an image from the center while maintaining the aspect ratio to fit within a specified size, then rounds the

/// corners to the specified radius.

public struct AspectScaledToFillSizeWithRoundedCornersFilter: CompositeImageFilter {

    /// Initializes the `AspectScaledToFillSizeWithRoundedCornersFilter` instance with the given size and radius.

    ///

    /// - parameter size:                     The size.

    /// - parameter radius:                   The radius.

    /// - parameter divideRadiusByImageScale: Whether to divide the radius by the image scale. Set to `true` when the

    ///                                       image has the same resolution for all screen scales such as @1x, @2x and

    ///                                       @3x (i.e. single image from web server). Set to `false` for images loaded

    ///                                       from an asset catalog with varying resolutions for each screen scale.

    ///                                       `false` by default.

    ///

    /// - returns: The new `AspectScaledToFillSizeWithRoundedCornersFilter` instance.

    public init(size: CGSize, radius: CGFloat, divideRadiusByImageScale: Bool = false) {

        filters = [AspectScaledToFillSizeFilter(size: size),

                   RoundedCornersFilter(radius: radius, divideRadiusByImageScale: divideRadiusByImageScale)]

    }

    /// The image filters to apply to the image in sequential order.

    public let filters: [ImageFilter]

}

// MARK: -

/// Scales an image to a specified size, then rounds the corners into a circle.

public struct ScaledToSizeCircleFilter: CompositeImageFilter {

    /// Initializes the `ScaledToSizeCircleFilter` instance with the given size.

    ///

    /// - parameter size: The size.

    ///

    /// - returns: The new `ScaledToSizeCircleFilter` instance.

    public init(size: CGSize) {

        filters = [ScaledToSizeFilter(size: size), CircleFilter()]

    }

    /// The image filters to apply to the image in sequential order.

    public let filters: [ImageFilter]

}

// MARK: -

/// Scales an image from the center while maintaining the aspect ratio to fit within a specified size, then rounds the

/// corners into a circle.

public struct AspectScaledToFillSizeCircleFilter: CompositeImageFilter {

    /// Initializes the `AspectScaledToFillSizeCircleFilter` instance with the given size.

    ///

    /// - parameter size: The size.

    ///

    /// - returns: The new `AspectScaledToFillSizeCircleFilter` instance.

    public init(size: CGSize) {

        filters = [AspectScaledToFillSizeFilter(size: size), CircleFilter()]

    }

    /// The image filters to apply to the image in sequential order.

    public let filters: [ImageFilter]

}

#endif