KFOptionsSetter.swift 33 KB

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  1. //
  2. // KFOptionsSetter.swift
  3. // Kingfisher
  4. //
  5. // Created by onevcat on 2020/12/22.
  6. //
  7. // Copyright (c) 2020 Wei Wang <onevcat@gmail.com>
  8. //
  9. // Permission is hereby granted, free of charge, to any person obtaining a copy
  10. // of this software and associated documentation files (the "Software"), to deal
  11. // in the Software without restriction, including without limitation the rights
  12. // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13. // copies of the Software, and to permit persons to whom the Software is
  14. // furnished to do so, subject to the following conditions:
  15. //
  16. // The above copyright notice and this permission notice shall be included in
  17. // all copies or substantial portions of the Software.
  18. //
  19. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20. // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21. // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  22. // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23. // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24. // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25. // THE SOFTWARE.
  26. import Foundation
  27. import CoreGraphics
  28. public protocol KFOptionSetter {
  29. var options: KingfisherParsedOptionsInfo { get nonmutating set }
  30. var onFailureDelegate: Delegate<KingfisherError, Void> { get }
  31. var onSuccessDelegate: Delegate<RetrieveImageResult, Void> { get }
  32. var onProgressDelegate: Delegate<(Int64, Int64), Void> { get }
  33. var delegateObserver: AnyObject { get }
  34. }
  35. extension KF.Builder: KFOptionSetter {
  36. public var delegateObserver: AnyObject { self }
  37. }
  38. // MARK: - Life cycles
  39. extension KFOptionSetter {
  40. /// Sets the progress block to current builder.
  41. /// - Parameter block: Called when the image downloading progress gets updated. If the response does not contain an
  42. /// `expectedContentLength`, this block will not be called. If `block` is `nil`, the callback
  43. /// will be reset.
  44. /// - Returns: A `Self` value with changes applied.
  45. public func onProgress(_ block: DownloadProgressBlock?) -> Self {
  46. onProgressDelegate.delegate(on: delegateObserver) { (observer, result) in
  47. block?(result.0, result.1)
  48. }
  49. return self
  50. }
  51. /// Sets the the done block to current builder.
  52. /// - Parameter block: Called when the image task successfully completes and the the image set is done. If `block`
  53. /// is `nil`, the callback will be reset.
  54. /// - Returns: A `KF.Builder` with changes applied.
  55. public func onSuccess(_ block: ((RetrieveImageResult) -> Void)?) -> Self {
  56. onSuccessDelegate.delegate(on: delegateObserver) { (observer, result) in
  57. block?(result)
  58. }
  59. return self
  60. }
  61. /// Sets the catch block to current builder.
  62. /// - Parameter block: Called when an error happens during the image task. If `block`
  63. /// is `nil`, the callback will be reset.
  64. /// - Returns: A `KF.Builder` with changes applied.
  65. public func onFailure(_ block: ((KingfisherError) -> Void)?) -> Self {
  66. onFailureDelegate.delegate(on: delegateObserver) { (observer, error) in
  67. block?(error)
  68. }
  69. return self
  70. }
  71. }
  72. // MARK: - Basic options settings.
  73. extension KFOptionSetter {
  74. /// Sets the target image cache for this task.
  75. /// - Parameter cache: The target cache is about to be used for the task.
  76. /// - Returns: A `Self` value with changes applied.
  77. ///
  78. /// Kingfisher will use the associated `ImageCache` object when handling related operations,
  79. /// including trying to retrieve the cached images and store the downloaded image to it.
  80. ///
  81. public func targetCache(_ cache: ImageCache) -> Self {
  82. options.targetCache = cache
  83. return self
  84. }
  85. /// Sets the target image cache to store the original downloaded image for this task.
  86. /// - Parameter cache: The target cache is about to be used for storing the original downloaded image from the task.
  87. /// - Returns: A `Self` value with changes applied.
  88. ///
  89. /// The `ImageCache` for storing and retrieving original images. If `originalCache` is
  90. /// contained in the options, it will be preferred for storing and retrieving original images.
  91. /// If there is no `.originalCache` in the options, `.targetCache` will be used to store original images.
  92. ///
  93. /// When using KingfisherManager to download and store an image, if `cacheOriginalImage` is
  94. /// applied in the option, the original image will be stored to this `originalCache`. At the
  95. /// same time, if a requested final image (with processor applied) cannot be found in `targetCache`,
  96. /// Kingfisher will try to search the original image to check whether it is already there. If found,
  97. /// it will be used and applied with the given processor. It is an optimization for not downloading
  98. /// the same image for multiple times.
  99. ///
  100. public func originalCache(_ cache: ImageCache) -> Self {
  101. options.originalCache = cache
  102. return self
  103. }
  104. /// Sets the downloader used to perform the image download task.
  105. /// - Parameter downloader: The downloader which is about to be used for downloading.
  106. /// - Returns: A `Self` value with changes applied.
  107. ///
  108. /// Kingfisher will use the set `ImageDownloader` object to download the requested images.
  109. public func downloader(_ downloader: ImageDownloader) -> Self {
  110. options.downloader = downloader
  111. return self
  112. }
  113. /// Sets the download priority for the image task.
  114. /// - Parameter priority: The download priority of image download task.
  115. /// - Returns: A `Self` value with changes applied.
  116. ///
  117. /// The `priority` value will be set as the priority of the image download task. The value for it should be
  118. /// between 0.0~1.0. You can choose a value between `URLSessionTask.defaultPriority`, `URLSessionTask.lowPriority`
  119. /// or `URLSessionTask.highPriority`. If this option not set, the default value (`URLSessionTask.defaultPriority`)
  120. /// will be used.
  121. public func downloadPriority(_ priority: Float) -> Self {
  122. options.downloadPriority = priority
  123. return self
  124. }
  125. /// Sets whether Kingfisher should ignore the cache and try to start a download task for the image source.
  126. /// - Parameter enabled: Enable the force refresh or not.
  127. /// - Returns: A `Self` value with changes applied.
  128. public func forceRefresh(_ enabled: Bool = true) -> Self {
  129. options.forceRefresh = enabled
  130. return self
  131. }
  132. /// Sets whether Kingfisher should try to retrieve the image from memory cache first. If not found, it ignores the
  133. /// disk cache and starts a download task for the image source.
  134. /// - Parameter enabled: Enable the memory-only cache searching or not.
  135. /// - Returns: A `Self` value with changes applied.
  136. ///
  137. /// This is useful when you want to display a changeable image behind the same url at the same app session, while
  138. /// avoiding download it for multiple times.
  139. public func fromMemoryCacheOrRefresh(_ enabled: Bool = true) -> Self {
  140. options.fromMemoryCacheOrRefresh = enabled
  141. return self
  142. }
  143. /// Sets whether the image should only be cached in memory but not in disk.
  144. /// - Parameter enabled: Whether the image should be only cache in memory or not.
  145. /// - Returns: A `Self` value with changes applied.
  146. public func cacheMemoryOnly(_ enabled: Bool = true) -> Self {
  147. options.cacheMemoryOnly = enabled
  148. return self
  149. }
  150. /// Sets whether Kingfisher should wait for caching operation to be completed before calling the
  151. /// `onSuccess` or `onFailure` block.
  152. /// - Parameter enabled: Whether Kingfisher should wait for caching operation.
  153. /// - Returns: A `Self` value with changes applied.
  154. public func waitForCache(_ enabled: Bool = true) -> Self {
  155. options.waitForCache = enabled
  156. return self
  157. }
  158. /// Sets whether Kingfisher should only try to retrieve the image from cache, but not from network.
  159. /// - Parameter enabled: Whether Kingfisher should only try to retrieve the image from cache.
  160. /// - Returns: A `Self` value with changes applied.
  161. ///
  162. /// If the image is not in cache, the image retrieving will fail with the
  163. /// `KingfisherError.cacheError` with `.imageNotExisting` as its reason.
  164. public func onlyFromCache(_ enabled: Bool = true) -> Self {
  165. options.onlyFromCache = enabled
  166. return self
  167. }
  168. /// Sets whether the image should be decoded in a background thread before using.
  169. /// - Parameter enabled: Whether the image should be decoded in a background thread before using.
  170. /// - Returns: A `Self` value with changes applied.
  171. ///
  172. /// Setting to `true` will decode the downloaded image data and do a off-screen rendering to extract pixel
  173. /// information in background. This can speed up display, but will cost more time and memory to prepare the image
  174. /// for using.
  175. public func backgroundDecode(_ enabled: Bool = true) -> Self {
  176. options.backgroundDecode = enabled
  177. return self
  178. }
  179. /// Sets the callback queue which is used as the target queue of dispatch callbacks when retrieving images from
  180. /// cache. If not set, Kingfisher will use main queue for callbacks.
  181. /// - Parameter queue: The target queue which the cache retrieving callback will be invoked on.
  182. /// - Returns: A `Self` value with changes applied.
  183. ///
  184. /// - Note:
  185. /// This option does not affect the callbacks for UI related extension methods or `KFImage` result handlers.
  186. /// You will always get the callbacks called from main queue.
  187. public func callbackQueue(_ queue: CallbackQueue) -> Self {
  188. options.callbackQueue = queue
  189. return self
  190. }
  191. /// Sets the scale factor value when converting retrieved data to an image.
  192. /// - Parameter factor: The scale factor value.
  193. /// - Returns: A `Self` value with changes applied.
  194. ///
  195. /// Specify the image scale, instead of your screen scale. You may need to set the correct scale when you dealing
  196. /// with 2x or 3x retina images. Otherwise, Kingfisher will convert the data to image object at `scale` 1.0.
  197. ///
  198. public func scaleFactor(_ factor: CGFloat) -> Self {
  199. options.scaleFactor = factor
  200. return self
  201. }
  202. /// Sets whether the original image should be cached even when the original image has been processed by any other
  203. /// `ImageProcessor`s.
  204. /// - Parameter enabled: Whether the original image should be cached.
  205. /// - Returns: A `Self` value with changes applied.
  206. ///
  207. /// If set and an `ImageProcessor` is used, Kingfisher will try to cache both the final result and original
  208. /// image. Kingfisher will have a chance to use the original image when another processor is applied to the same
  209. /// resource, instead of downloading it again. You can use `.originalCache` to specify a cache or the original
  210. /// images if necessary.
  211. ///
  212. /// The original image will be only cached to disk storage.
  213. ///
  214. public func cacheOriginalImage(_ enabled: Bool = true) -> Self {
  215. options.cacheOriginalImage = enabled
  216. return self
  217. }
  218. /// Sets writing options for an original image on a first write
  219. /// - Parameter writingOptions: Options to control the writing of data to a disk storage.
  220. /// - Returns: A `Self` value with changes applied.
  221. /// If set, options will be passed the store operation for a new files.
  222. ///
  223. /// This is useful if you want to implement file enctyption on first write - eg [.completeFileProtection]
  224. ///
  225. public func diskStoreWriteOptions(_ writingOptions: Data.WritingOptions) -> Self {
  226. options.diskStoreWriteOptions = writingOptions
  227. return self
  228. }
  229. /// Sets whether the disk storage loading should happen in the same calling queue.
  230. /// - Parameter enabled: Whether the disk storage loading should happen in the same calling queue.
  231. /// - Returns: A `Self` value with changes applied.
  232. ///
  233. /// By default, disk storage file loading
  234. /// happens in its own queue with an asynchronous dispatch behavior. Although it provides better non-blocking disk
  235. /// loading performance, it also causes a flickering when you reload an image from disk, if the image view already
  236. /// has an image set.
  237. ///
  238. /// Set this options will stop that flickering by keeping all loading in the same queue (typically the UI queue
  239. /// if you are using Kingfisher's extension methods to set an image), with a tradeoff of loading performance.
  240. ///
  241. public func loadDiskFileSynchronously(_ enabled: Bool = true) -> Self {
  242. options.loadDiskFileSynchronously = enabled
  243. return self
  244. }
  245. /// Sets a queue on which the image processing should happen.
  246. /// - Parameter queue: The queue on which the image processing should happen.
  247. /// - Returns: A `Self` value with changes applied.
  248. ///
  249. /// By default, Kingfisher uses a pre-defined serial
  250. /// queue to process images. Use this option to change this behavior. For example, specify a `.mainCurrentOrAsync`
  251. /// to let the image be processed in main queue to prevent a possible flickering (but with a possibility of
  252. /// blocking the UI, especially if the processor needs a lot of time to run).
  253. public func processingQueue(_ queue: CallbackQueue?) -> Self {
  254. options.processingQueue = queue
  255. return self
  256. }
  257. /// Sets the alternative sources that will be used when loading of the original input `Source` fails.
  258. /// - Parameter sources: The alternative sources will be used.
  259. /// - Returns: A `Self` value with changes applied.
  260. ///
  261. /// Values of the `sources` array will be used to start a new image loading task if the previous task
  262. /// fails due to an error. The image source loading process will stop as soon as a source is loaded successfully.
  263. /// If all `sources` are used but the loading is still failing, an `imageSettingError` with
  264. /// `alternativeSourcesExhausted` as its reason will be given out in the `catch` block.
  265. ///
  266. /// This is useful if you want to implement a fallback solution for setting image.
  267. ///
  268. /// User cancellation will not trigger the alternative source loading.
  269. public func alternativeSources(_ sources: [Source]?) -> Self {
  270. options.alternativeSources = sources
  271. return self
  272. }
  273. /// Sets a retry strategy that will be used when something gets wrong during the image retrieving.
  274. /// - Parameter strategy: The provided strategy to define how the retrying should happen.
  275. /// - Returns: A `Self` value with changes applied.
  276. public func retry(_ strategy: RetryStrategy?) -> Self {
  277. options.retryStrategy = strategy
  278. return self
  279. }
  280. /// Sets a retry strategy with a max retry count and retrying interval.
  281. /// - Parameters:
  282. /// - maxCount: The maximum count before the retry stops.
  283. /// - interval: The time interval between each retry attempt.
  284. /// - Returns: A `Self` value with changes applied.
  285. ///
  286. /// This defines the simplest retry strategy, which retry a failing request for several times, with some certain
  287. /// interval between each time. For example, `.retry(maxCount: 3, interval: .second(3))` means attempt for at most
  288. /// three times, and wait for 3 seconds if a previous retry attempt fails, then start a new attempt.
  289. public func retry(maxCount: Int, interval: DelayRetryStrategy.Interval = .seconds(3)) -> Self {
  290. let strategy = DelayRetryStrategy(maxRetryCount: maxCount, retryInterval: interval)
  291. options.retryStrategy = strategy
  292. return self
  293. }
  294. /// Sets the `Source` should be loaded when user enables Low Data Mode and the original source fails with an
  295. /// `NSURLErrorNetworkUnavailableReason.constrained` error.
  296. /// - Parameter source: The `Source` will be loaded under low data mode.
  297. /// - Returns: A `Self` value with changes applied.
  298. ///
  299. /// When this option is set, the
  300. /// `allowsConstrainedNetworkAccess` property of the request for the original source will be set to `false` and the
  301. /// `Source` in associated value will be used to retrieve the image for low data mode. Usually, you can provide a
  302. /// low-resolution version of your image or a local image provider to display a placeholder.
  303. ///
  304. /// If not set or the `source` is `nil`, the device Low Data Mode will be ignored and the original source will
  305. /// be loaded following the system default behavior, in a normal way.
  306. public func lowDataModeSource(_ source: Source?) -> Self {
  307. options.lowDataModeSource = source
  308. return self
  309. }
  310. /// Sets whether the image setting for an image view should happen with transition even when retrieved from cache.
  311. /// - Parameter enabled: Enable the force transition or not.
  312. /// - Returns: A `Self` with changes applied.
  313. public func forceTransition(_ enabled: Bool = true) -> Self {
  314. options.forceTransition = enabled
  315. return self
  316. }
  317. /// Sets the image that will be used if an image retrieving task fails.
  318. /// - Parameter image: The image that will be used when something goes wrong.
  319. /// - Returns: A `Self` with changes applied.
  320. ///
  321. /// If set and an image retrieving error occurred Kingfisher will set provided image (or empty)
  322. /// in place of requested one. It's useful when you don't want to show placeholder
  323. /// during loading time but wants to use some default image when requests will be failed.
  324. ///
  325. public func onFailureImage(_ image: KFCrossPlatformImage?) -> Self {
  326. options.onFailureImage = .some(image)
  327. return self
  328. }
  329. }
  330. // MARK: - Request Modifier
  331. extension KFOptionSetter {
  332. /// Sets an `ImageDownloadRequestModifier` to change the image download request before it being sent.
  333. /// - Parameter modifier: The modifier will be used to change the request before it being sent.
  334. /// - Returns: A `Self` value with changes applied.
  335. ///
  336. /// This is the last chance you can modify the image download request. You can modify the request for some
  337. /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
  338. ///
  339. public func requestModifier(_ modifier: AsyncImageDownloadRequestModifier) -> Self {
  340. options.requestModifier = modifier
  341. return self
  342. }
  343. /// Sets a block to change the image download request before it being sent.
  344. /// - Parameter modifyBlock: The modifying block will be called to change the request before it being sent.
  345. /// - Returns: A `Self` value with changes applied.
  346. ///
  347. /// This is the last chance you can modify the image download request. You can modify the request for some
  348. /// customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url mapping.
  349. ///
  350. public func requestModifier(_ modifyBlock: @escaping (inout URLRequest) -> Void) -> Self {
  351. options.requestModifier = AnyModifier { r -> URLRequest? in
  352. var request = r
  353. modifyBlock(&request)
  354. return request
  355. }
  356. return self
  357. }
  358. }
  359. // MARK: - Redirect Handler
  360. extension KFOptionSetter {
  361. /// The `ImageDownloadRedirectHandler` argument will be used to change the request before redirection.
  362. /// This is the possibility you can modify the image download request during redirect. You can modify the request for
  363. /// some customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url
  364. /// mapping.
  365. /// The original redirection request will be sent without any modification by default.
  366. /// - Parameter handler: The handler will be used for redirection.
  367. /// - Returns: A `Self` value with changes applied.
  368. public func redirectHandler(_ handler: ImageDownloadRedirectHandler) -> Self {
  369. options.redirectHandler = handler
  370. return self
  371. }
  372. /// The `block` will be used to change the request before redirection.
  373. /// This is the possibility you can modify the image download request during redirect. You can modify the request for
  374. /// some customizing purpose, such as adding auth token to the header, do basic HTTP auth or something like url
  375. /// mapping.
  376. /// The original redirection request will be sent without any modification by default.
  377. /// - Parameter block: The block will be used for redirection.
  378. /// - Returns: A `Self` value with changes applied.
  379. public func redirectHandler(_ block: @escaping (KF.RedirectPayload) -> Void) -> Self {
  380. let redirectHandler = AnyRedirectHandler { (task, response, request, handler) in
  381. let payload = KF.RedirectPayload(
  382. task: task, response: response, newRequest: request, completionHandler: handler
  383. )
  384. block(payload)
  385. }
  386. options.redirectHandler = redirectHandler
  387. return self
  388. }
  389. }
  390. // MARK: - Processor
  391. extension KFOptionSetter {
  392. /// Sets an image processor for the image task. It replaces the current image processor settings.
  393. ///
  394. /// - Parameter processor: The processor you want to use to process the image after it is downloaded.
  395. /// - Returns: A `Self` value with changes applied.
  396. ///
  397. /// - Note:
  398. /// To append a processor to current ones instead of replacing them all, use `appendProcessor(_:)`.
  399. public func setProcessor(_ processor: ImageProcessor) -> Self {
  400. options.processor = processor
  401. return self
  402. }
  403. /// Sets an array of image processors for the image task. It replaces the current image processor settings.
  404. /// - Parameter processors: An array of processors. The processors inside this array will be concatenated one by one
  405. /// to form a processor pipeline.
  406. /// - Returns: A `Self` value with changes applied.
  407. ///
  408. /// - Note: To append processors to current ones instead of replacing them all, concatenate them by `|>`, then use
  409. /// `appendProcessor(_:)`.
  410. public func setProcessors(_ processors: [ImageProcessor]) -> Self {
  411. switch processors.count {
  412. case 0:
  413. options.processor = DefaultImageProcessor.default
  414. case 1...:
  415. options.processor = processors.dropFirst().reduce(processors[0]) { $0 |> $1 }
  416. default:
  417. assertionFailure("Never happen")
  418. }
  419. return self
  420. }
  421. /// Appends a processor to the current set processors.
  422. /// - Parameter processor: The processor which will be appended to current processor settings.
  423. /// - Returns: A `Self` value with changes applied.
  424. public func appendProcessor(_ processor: ImageProcessor) -> Self {
  425. options.processor = options.processor |> processor
  426. return self
  427. }
  428. /// Appends a `RoundCornerImageProcessor` to current processors.
  429. /// - Parameters:
  430. /// - radius: The radius will be applied in processing. Specify a certain point value with `.point`, or a fraction
  431. /// of the target image with `.widthFraction`. or `.heightFraction`. For example, given a square image
  432. /// with width and height equals, `.widthFraction(0.5)` means use half of the length of size and makes
  433. /// the final image a round one.
  434. /// - targetSize: Target size of output image should be. If `nil`, the image will keep its original size after processing.
  435. /// - corners: The target corners which will be applied rounding.
  436. /// - backgroundColor: Background color of the output image. If `nil`, it will use a transparent background.
  437. /// - Returns: A `Self` value with changes applied.
  438. public func roundCorner(
  439. radius: Radius,
  440. targetSize: CGSize? = nil,
  441. roundingCorners corners: RectCorner = .all,
  442. backgroundColor: KFCrossPlatformColor? = nil
  443. ) -> Self
  444. {
  445. let processor = RoundCornerImageProcessor(
  446. radius: radius,
  447. targetSize: targetSize,
  448. roundingCorners: corners,
  449. backgroundColor: backgroundColor
  450. )
  451. return appendProcessor(processor)
  452. }
  453. /// Appends a `BlurImageProcessor` to current processors.
  454. /// - Parameter radius: Blur radius for the simulated Gaussian blur.
  455. /// - Returns: A `Self` value with changes applied.
  456. public func blur(radius: CGFloat) -> Self {
  457. appendProcessor(
  458. BlurImageProcessor(blurRadius: radius)
  459. )
  460. }
  461. /// Appends a `OverlayImageProcessor` to current processors.
  462. /// - Parameters:
  463. /// - color: Overlay color will be used to overlay the input image.
  464. /// - fraction: Fraction will be used when overlay the color to image.
  465. /// - Returns: A `Self` value with changes applied.
  466. public func overlay(color: KFCrossPlatformColor, fraction: CGFloat = 0.5) -> Self {
  467. appendProcessor(
  468. OverlayImageProcessor(overlay: color, fraction: fraction)
  469. )
  470. }
  471. /// Appends a `TintImageProcessor` to current processors.
  472. /// - Parameter color: Tint color will be used to tint the input image.
  473. /// - Returns: A `Self` value with changes applied.
  474. public func tint(color: KFCrossPlatformColor) -> Self {
  475. appendProcessor(
  476. TintImageProcessor(tint: color)
  477. )
  478. }
  479. /// Appends a `BlackWhiteProcessor` to current processors.
  480. /// - Returns: A `Self` value with changes applied.
  481. public func blackWhite() -> Self {
  482. appendProcessor(
  483. BlackWhiteProcessor()
  484. )
  485. }
  486. /// Appends a `CroppingImageProcessor` to current processors.
  487. /// - Parameters:
  488. /// - size: Target size of output image should be.
  489. /// - anchor: Anchor point from which the output size should be calculate. The anchor point is consisted by two
  490. /// values between 0.0 and 1.0. It indicates a related point in current image.
  491. /// See `CroppingImageProcessor.init(size:anchor:)` for more.
  492. /// - Returns: A `Self` value with changes applied.
  493. public func cropping(size: CGSize, anchor: CGPoint = .init(x: 0.5, y: 0.5)) -> Self {
  494. appendProcessor(
  495. CroppingImageProcessor(size: size, anchor: anchor)
  496. )
  497. }
  498. /// Appends a `DownsamplingImageProcessor` to current processors.
  499. ///
  500. /// Compared to `ResizingImageProcessor`, the `DownsamplingImageProcessor` does not render the original images and
  501. /// then resize it. Instead, it downsamples the input data directly to a thumbnail image. So it is a more efficient
  502. /// than `ResizingImageProcessor`. Prefer to use `DownsamplingImageProcessor` as possible
  503. /// as you can than the `ResizingImageProcessor`.
  504. ///
  505. /// Only CG-based images are supported. Animated images (like GIF) is not supported.
  506. ///
  507. /// - Parameter size: Target size of output image should be. It should be smaller than the size of input image.
  508. /// If it is larger, the result image will be the same size of input data without downsampling.
  509. /// - Returns: A `Self` value with changes applied.
  510. public func downsampling(size: CGSize) -> Self {
  511. let processor = DownsamplingImageProcessor(size: size)
  512. if options.processor == DefaultImageProcessor.default {
  513. return setProcessor(processor)
  514. } else {
  515. return appendProcessor(processor)
  516. }
  517. }
  518. /// Appends a `ResizingImageProcessor` to current processors.
  519. ///
  520. /// If you need to resize a data represented image to a smaller size, use `DownsamplingImageProcessor`
  521. /// instead, which is more efficient and uses less memory.
  522. ///
  523. /// - Parameters:
  524. /// - referenceSize: The reference size for resizing operation in point.
  525. /// - mode: Target content mode of output image should be. Default is `.none`.
  526. /// - Returns: A `Self` value with changes applied.
  527. public func resizing(referenceSize: CGSize, mode: ContentMode = .none) -> Self {
  528. appendProcessor(
  529. ResizingImageProcessor(referenceSize: referenceSize, mode: mode)
  530. )
  531. }
  532. }
  533. // MARK: - Cache Serializer
  534. extension KFOptionSetter {
  535. /// Uses a given `CacheSerializer` to convert some data to an image object for retrieving from disk cache or vice
  536. /// versa for storing to disk cache.
  537. /// - Parameter cacheSerializer: The `CacheSerializer` which will be used.
  538. /// - Returns: A `Self` value with changes applied.
  539. public func serialize(by cacheSerializer: CacheSerializer) -> Self {
  540. options.cacheSerializer = cacheSerializer
  541. return self
  542. }
  543. /// Uses a given format to serializer the image data to disk. It converts the image object to the give data format.
  544. /// - Parameters:
  545. /// - format: The desired data encoding format when store the image on disk.
  546. /// - jpegCompressionQuality: If the format is `.JPEG`, it specify the compression quality when converting the
  547. /// image to a JPEG data. Otherwise, it is ignored.
  548. /// - Returns: A `Self` value with changes applied.
  549. public func serialize(as format: ImageFormat, jpegCompressionQuality: CGFloat? = nil) -> Self {
  550. let cacheSerializer: FormatIndicatedCacheSerializer
  551. switch format {
  552. case .JPEG:
  553. cacheSerializer = .jpeg(compressionQuality: jpegCompressionQuality ?? 1.0)
  554. case .PNG:
  555. cacheSerializer = .png
  556. case .GIF:
  557. cacheSerializer = .gif
  558. case .unknown:
  559. cacheSerializer = .png
  560. }
  561. options.cacheSerializer = cacheSerializer
  562. return self
  563. }
  564. }
  565. // MARK: - Image Modifier
  566. extension KFOptionSetter {
  567. /// Sets an `ImageModifier` to the image task. Use this to modify the fetched image object properties if needed.
  568. ///
  569. /// If the image was fetched directly from the downloader, the modifier will run directly after the
  570. /// `ImageProcessor`. If the image is being fetched from a cache, the modifier will run after the `CacheSerializer`.
  571. /// - Parameter modifier: The `ImageModifier` which will be used to modify the image object.
  572. /// - Returns: A `Self` value with changes applied.
  573. public func imageModifier(_ modifier: ImageModifier?) -> Self {
  574. options.imageModifier = modifier
  575. return self
  576. }
  577. /// Sets a block to modify the image object. Use this to modify the fetched image object properties if needed.
  578. ///
  579. /// If the image was fetched directly from the downloader, the modifier block will run directly after the
  580. /// `ImageProcessor`. If the image is being fetched from a cache, the modifier will run after the `CacheSerializer`.
  581. ///
  582. /// - Parameter block: The block which is used to modify the image object.
  583. /// - Returns: A `Self` value with changes applied.
  584. public func imageModifier(_ block: @escaping (inout KFCrossPlatformImage) throws -> Void) -> Self {
  585. let modifier = AnyImageModifier { image -> KFCrossPlatformImage in
  586. var image = image
  587. try block(&image)
  588. return image
  589. }
  590. options.imageModifier = modifier
  591. return self
  592. }
  593. }
  594. // MARK: - Cache Expiration
  595. extension KFOptionSetter {
  596. /// Sets the expiration setting for memory cache of this image task.
  597. ///
  598. /// By default, the underlying `MemoryStorage.Backend` uses the
  599. /// expiration in its config for all items. If set, the `MemoryStorage.Backend` will use this value to overwrite
  600. /// the config setting for this caching item.
  601. ///
  602. /// - Parameter expiration: The expiration setting used in cache storage.
  603. /// - Returns: A `Self` value with changes applied.
  604. public func memoryCacheExpiration(_ expiration: StorageExpiration?) -> Self {
  605. options.memoryCacheExpiration = expiration
  606. return self
  607. }
  608. /// Sets the expiration extending setting for memory cache. The item expiration time will be incremented by this
  609. /// value after access.
  610. ///
  611. /// By default, the underlying `MemoryStorage.Backend` uses the initial cache expiration as extending
  612. /// value: .cacheTime.
  613. ///
  614. /// To disable extending option at all, sets `.none` to it.
  615. ///
  616. /// - Parameter extending: The expiration extending setting used in cache storage.
  617. /// - Returns: A `Self` value with changes applied.
  618. public func memoryCacheAccessExtending(_ extending: ExpirationExtending) -> Self {
  619. options.memoryCacheAccessExtendingExpiration = extending
  620. return self
  621. }
  622. /// Sets the expiration setting for disk cache of this image task.
  623. ///
  624. /// By default, the underlying `DiskStorage.Backend` uses the expiration in its config for all items. If set,
  625. /// the `DiskStorage.Backend` will use this value to overwrite the config setting for this caching item.
  626. ///
  627. /// - Parameter expiration: The expiration setting used in cache storage.
  628. /// - Returns: A `Self` value with changes applied.
  629. public func diskCacheExpiration(_ expiration: StorageExpiration?) -> Self {
  630. options.diskCacheExpiration = expiration
  631. return self
  632. }
  633. /// Sets the expiration extending setting for disk cache. The item expiration time will be incremented by this
  634. /// value after access.
  635. ///
  636. /// By default, the underlying `DiskStorage.Backend` uses the initial cache expiration as extending
  637. /// value: .cacheTime.
  638. ///
  639. /// To disable extending option at all, sets `.none` to it.
  640. ///
  641. /// - Parameter extending: The expiration extending setting used in cache storage.
  642. /// - Returns: A `Self` value with changes applied.
  643. public func diskCacheAccessExtending(_ extending: ExpirationExtending) -> Self {
  644. options.diskCacheAccessExtendingExpiration = extending
  645. return self
  646. }
  647. }