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//
// ImageModifier.swift
// Kingfisher
//
// Created by Ethan Gill on 2017/11/28.
//
// Copyright (c) 2018 Ethan Gill <ethan.gill@me.com>
//
// 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
/// An `ImageModifier` can be used to change properties on an Image in between
/// cache serialization and use of the image.
public protocol ImageModifier {
/// Modify an input `Image`.
///
/// - parameter image: Image which will be modified by `self`
///
/// - returns: The modified image.
///
/// - Note: The return value will be unmodified if modifying is not possible on
/// the current platform.
/// - Note: Most modifiers support UIImage or NSImage, but not CGImage.
func modify(_ image: Image) -> Image
}
extension ImageModifier {
func modify(_ image: Image?) -> Image? {
guard let image = image else {
return nil
}
return modify(image)
}
}
typealias ModifierImp = ((Image) -> Image)
fileprivate struct GeneralModifier: ImageModifier {
let identifier: String
let m: ModifierImp
func modify(_ image: Image) -> Image {
return m(image)
}
}
/// The default modifier.
/// Does nothing and returns the image it was given
public struct DefaultImageModifier: ImageModifier {
/// A default `DefaultImageModifier` which can be used everywhere.
public static let `default` = DefaultImageModifier()
/// Initialize a `DefaultImageModifier`
private init() {}
/// Modify an input `Image`.
///
/// - parameter image: Image which will be modified by `self`
///
/// - returns: The modified image.
///
/// - Note: See documentation of `ImageModifier` protocol for more.
public func modify(_ image: Image) -> Image {
return image
}
}
/// A custom modifier.
/// Can be initialized with a block to modify images in a custom way
public struct AnyImageModifier: ImageModifier {
/// A block which modifies images, or returns the original image
/// if modification cannot be performed.
let block: (Image) -> Image
/// Initialize an `AnyImageModifier`
public init(modify: @escaping (Image) -> Image) {
block = modify
}
/// Modifies an input `Image` using this `AnyImageModifier`'s `block`.
///
/// - parameter image: Image which will be modified by `self`
///
/// - returns: The modified image.
///
/// - Note: See documentation of `ImageModifier` protocol for more.
public func modify(_ image: Image) -> Image {
return block(image)
}
}
#if os(iOS) || os(tvOS) || os(watchOS)
import UIKit
/// Modifier for setting the rendering mode of images.
/// Only UI-based images are supported; if a non-UI image is passed in, the
/// modifier will do nothing.
public struct RenderingModeImageModifier: ImageModifier {
/// The rendering mode to apply to the image.
public let renderingMode: UIImage.RenderingMode
/// Initialize a `RenderingModeImageModifier`
///
/// - parameter renderingMode: The rendering mode to apply to the image.
/// Default is .automatic
public init(renderingMode: UIImage.RenderingMode = .automatic) {
self.renderingMode = renderingMode
}
/// Modify an input `Image`.
///
/// - parameter image: Image which will be modified by `self`
///
/// - returns: The modified image.
///
/// - Note: See documentation of `ImageModifier` protocol for more.
public func modify(_ image: Image) -> Image {
return image.withRenderingMode(renderingMode)
}
}
/// Modifier for setting the `flipsForRightToLeftLayoutDirection` property of images.
/// Only UI-based images are supported; if a non-UI image is passed in, the
/// modifier will do nothing.
public struct FlipsForRightToLeftLayoutDirectionImageModifier: ImageModifier {
/// Initialize a `FlipsForRightToLeftLayoutDirectionImageModifier`
///
/// - Note: On versions of iOS lower than 9.0, the image will be returned
/// unmodified.
public init() {}
/// Modify an input `Image`.
///
/// - parameter image: Image which will be modified by `self`
///
/// - returns: The modified image.
///
/// - Note: See documentation of `ImageModifier` protocol for more.
public func modify(_ image: Image) -> Image {
if #available(iOS 9.0, *) {
return image.imageFlippedForRightToLeftLayoutDirection()
} else {
return image
}
}
}
/// Modifier for setting the `alignmentRectInsets` property of images.
/// Only UI-based images are supported; if a non-UI image is passed in, the
/// modifier will do nothing.
public struct AlignmentRectInsetsImageModifier: ImageModifier {
/// The alignment insets to apply to the image
public let alignmentInsets: UIEdgeInsets
/// Initialize a `AlignmentRectInsetsImageModifier`
public init(alignmentInsets: UIEdgeInsets) {
self.alignmentInsets = alignmentInsets
}
/// Modify an input `Image`.
///
/// - parameter image: Image which will be modified by `self`
///
/// - returns: The modified image.
///
/// - Note: See documentation of `ImageModifier` protocol for more.
public func modify(_ image: Image) -> Image {
return image.withAlignmentRectInsets(alignmentInsets)
}
}
#endif