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Cache scaled images

This commit is contained in:
Shadowfacts 2021-01-17 13:27:30 -05:00
parent 6dee0957ea
commit 04a6fe807e
2 changed files with 36 additions and 11 deletions
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13
Tusker/Caching/ImageCache.swift
View File

@ -11,7 +11,7 @@ import Cache
class ImageCache {
static let avatars = ImageCache(name: "Avatars", memoryExpiry: .seconds(60 * 60), diskExpiry: .seconds(60 * 60 * 24))
static let avatars = ImageCache(name: "Avatars", memoryExpiry: .seconds(60 * 60), diskExpiry: .seconds(60 * 60 * 24), desiredSize: CGSize(width: 50, height: 50))
static let headers = ImageCache(name: "Headers", memoryExpiry: .seconds(60 * 5), diskExpiry: .seconds(60 * 60))
static let attachments = ImageCache(name: "Attachments", memoryExpiry: .seconds(60 * 2))
static let emojis = ImageCache(name: "Emojis", memoryExpiry: .seconds(60 * 5), diskExpiry: .seconds(60 * 60))
@ -28,8 +28,10 @@ class ImageCache {
private var backgroundQueue = DispatchQueue(label: "ImageCache completion queue", qos: .default)
init(name: String, memoryExpiry: Expiry, diskExpiry: Expiry? = nil) {
self.cache = ImageDataCache(name: name, memoryExpiry: memoryExpiry, diskExpiry: diskExpiry, storeOriginalDataInMemory: diskExpiry == nil)
init(name: String, memoryExpiry: Expiry, diskExpiry: Expiry? = nil, desiredSize: CGSize? = nil) {
// todo: might not always want to use UIScreen.main for this, e.g. Catalyst?
let pixelSize = desiredSize?.applying(.init(scaleX: UIScreen.main.scale, y: UIScreen.main.scale))
self.cache = ImageDataCache(name: name, memoryExpiry: memoryExpiry, diskExpiry: diskExpiry, storeOriginalDataInMemory: diskExpiry == nil, desiredPixelSize: pixelSize)
}
func get(_ url: URL, completion: ((Data?, UIImage?) -> Void)?) -> Request? {
@ -49,9 +51,8 @@ class ImageCache {
return group.addCallback(completion)
} else {
let group = RequestGroup(url: url) { (data, image) in
if let data = data,
let image = UIImage(data: data) {
try? self.cache.set(key, data: data, image: image)
if let data = data {
try? self.cache.set(key, data: data)
}
self.groups.removeValueWithoutReturning(forKey: url)
}

34
Tusker/Caching/ImageDataCache.swift
View File

@ -15,8 +15,9 @@ class ImageDataCache {
private let disk: DiskStorage<Data>?
private let storeOriginalDataInMemory: Bool
private let desiredPixelSize: CGSize?
init(name: String, memoryExpiry: Expiry, diskExpiry: Expiry?, storeOriginalDataInMemory: Bool) {
init(name: String, memoryExpiry: Expiry, diskExpiry: Expiry?, storeOriginalDataInMemory: Bool, desiredPixelSize: CGSize?) {
let memoryConfig = MemoryConfig(expiry: memoryExpiry)
self.memory = MemoryStorage(config: memoryConfig)
@ -28,6 +29,7 @@ class ImageDataCache {
}
self.storeOriginalDataInMemory = storeOriginalDataInMemory
self.desiredPixelSize = desiredPixelSize
}
func has(_ key: String) throws -> Bool {
@ -42,10 +44,9 @@ class ImageDataCache {
}
func get(_ key: String) throws -> Entry? {
if try memory.existsObject(forKey: key) {
return try! memory.object(forKey: key)
if let memoryEntry = try? memory.object(forKey: key) {
return memoryEntry
} else if let disk = self.disk,
try disk.existsObject(forKey: key),
let data = try? disk.object(forKey: key),
let image = UIImage(data: data) {
return Entry(data: data, image: image)
@ -62,7 +63,9 @@ class ImageDataCache {
return try get(key)?.data
}
func set(_ key: String, data: Data, image: UIImage) throws {
func set(_ key: String, data: Data) throws {
guard let image = scaleImageIfDesired(data: data) else { return }
let entry = Entry(data: storeOriginalDataInMemory ? data : nil, image: image)
memory.setObject(entry, forKey: key)
@ -76,6 +79,27 @@ class ImageDataCache {
try? disk?.removeAll()
}
private func scaleImageIfDesired(data: Data) -> UIImage? {
guard let desiredPixelSize = desiredPixelSize,
let source = CGImageSourceCreateWithData(data as CFData, [kCGImageSourceShouldCache: false] as CFDictionary) else {
return UIImage(data: data)
}
let maxDimension = max(desiredPixelSize.width, desiredPixelSize.height)
let downsampleOptions = [
kCGImageSourceCreateThumbnailFromImageAlways: true,
kCGImageSourceShouldCacheImmediately: true,
kCGImageSourceCreateThumbnailWithTransform: true,
kCGImageSourceThumbnailMaxPixelSize: maxDimension
] as CFDictionary
if let downsampled = CGImageSourceCreateThumbnailAtIndex(source, 0, downsampleOptions) {
return UIImage(cgImage: downsampled)
} else {
return UIImage(data: data)
}
}
}
extension ImageDataCache {