Signal-iOS/SignalMessaging/Views/CVText.swift
2020-12-23 10:49:48 -08:00

457 lines
15 KiB
Swift

//
// Copyright (c) 2020 Open Whisper Systems. All rights reserved.
//
import Foundation
private typealias CacheKey = String
public enum CVTextValue: Equatable, Hashable {
case text(text: String)
case attributedText(attributedText: NSAttributedString)
func apply(label: UILabel) {
switch self {
case .text(let text):
label.text = text
case .attributedText(let attributedText):
label.attributedText = attributedText
}
}
func apply(textView: UITextView) {
switch self {
case .text(let text):
textView.text = text
case .attributedText(let attributedText):
textView.attributedText = attributedText
}
}
public var stringValue: String {
switch self {
case .text(let text):
return text
case .attributedText(let attributedText):
return attributedText.string
}
}
var debugDescription: String {
switch self {
case .text(let text):
return "text: \(text)"
case .attributedText(let attributedText):
return "attributedText: \(attributedText.string)"
}
}
fileprivate var cacheKey: CacheKey {
switch self {
case .text(let text):
return "t\(text)"
case .attributedText(let attributedText):
return "a\(attributedText.description)"
}
}
}
// MARK: - UILabel
public struct CVLabelConfig {
fileprivate let text: CVTextValue
public let font: UIFont
public let textColor: UIColor
public let numberOfLines: Int
public let lineBreakMode: NSLineBreakMode
public let textAlignment: NSTextAlignment?
public init(text: String,
font: UIFont,
textColor: UIColor,
numberOfLines: Int = 1,
lineBreakMode: NSLineBreakMode = .byWordWrapping,
textAlignment: NSTextAlignment? = nil) {
self.text = .text(text: text)
self.font = font
self.textColor = textColor
self.numberOfLines = numberOfLines
self.lineBreakMode = lineBreakMode
self.textAlignment = textAlignment
}
public init(attributedText: NSAttributedString,
font: UIFont,
textColor: UIColor,
numberOfLines: Int = 1,
lineBreakMode: NSLineBreakMode = .byWordWrapping,
textAlignment: NSTextAlignment? = nil) {
self.text = .attributedText(attributedText: attributedText)
self.font = font
self.textColor = textColor
self.numberOfLines = numberOfLines
self.lineBreakMode = lineBreakMode
self.textAlignment = textAlignment
}
func applyForMeasurement(label: UILabel) {
label.font = self.font
label.numberOfLines = self.numberOfLines
label.lineBreakMode = self.lineBreakMode
// Skip textColor, textAlignment.
// Apply text last, to protect attributed text attributes.
// There are also perf benefits.
self.text.apply(label: label)
}
public func applyForRendering(label: UILabel) {
label.font = self.font
label.numberOfLines = self.numberOfLines
label.lineBreakMode = self.lineBreakMode
label.textColor = self.textColor
if let textAlignment = textAlignment {
label.textAlignment = textAlignment
} else {
label.textAlignment = .natural
}
// Apply text last, to protect attributed text attributes.
// There are also perf benefits.
self.text.apply(label: label)
}
public func measure(maxWidth: CGFloat) -> CGSize {
CVText.measureLabel(config: self, maxWidth: maxWidth)
}
public var stringValue: String {
text.stringValue
}
public var debugDescription: String {
"CVLabelConfig: \(text.debugDescription)"
}
fileprivate var cacheKey: CacheKey {
// textColor doesn't affect measurement.
"\(text.cacheKey),\(font.fontName),\(font.pointSize),\(numberOfLines),\(lineBreakMode.rawValue),\(textAlignment?.rawValue ?? 0)"
}
}
// MARK: - UITextView
public struct CVTextViewConfig {
fileprivate let text: CVTextValue
public let font: UIFont
public let textColor: UIColor
public let textAlignment: NSTextAlignment?
public let linkTextAttributes: [NSAttributedString.Key: Any]?
public init(text: String,
font: UIFont,
textColor: UIColor,
textAlignment: NSTextAlignment? = nil,
linkTextAttributes: [NSAttributedString.Key: Any]? = nil) {
self.text = .text(text: text)
self.font = font
self.textColor = textColor
self.textAlignment = textAlignment
self.linkTextAttributes = linkTextAttributes
}
public init(attributedText: NSAttributedString,
font: UIFont,
textColor: UIColor,
textAlignment: NSTextAlignment? = nil,
linkTextAttributes: [NSAttributedString.Key: Any]? = nil) {
self.text = .attributedText(attributedText: attributedText)
self.font = font
self.textColor = textColor
self.textAlignment = textAlignment
self.linkTextAttributes = linkTextAttributes
}
func applyForMeasurement(textView: UITextView) {
textView.font = self.font
if let linkTextAttributes = linkTextAttributes {
textView.linkTextAttributes = linkTextAttributes
}
// Skip textColor, textAlignment.
// Apply text last, to protect attributed text attributes.
// There are also perf benefits.
self.text.apply(textView: textView)
}
public func applyForRendering(textView: UITextView) {
textView.font = self.font
textView.textColor = self.textColor
if let textAlignment = textAlignment {
textView.textAlignment = textAlignment
} else {
textView.textAlignment = .natural
}
if let linkTextAttributes = linkTextAttributes {
textView.linkTextAttributes = linkTextAttributes
} else {
textView.linkTextAttributes = [:]
}
// Apply text last, to protect attributed text attributes.
// There are also perf benefits.
self.text.apply(textView: textView)
}
public func measure(maxWidth: CGFloat) -> CGSize {
CVText.measureTextView(config: self, maxWidth: maxWidth)
}
public var stringValue: String {
text.stringValue
}
public var debugDescription: String {
"CVTextViewConfig: \(text.debugDescription)"
}
fileprivate var cacheKey: CacheKey {
// textColor and linkTextAttributes (for the attributes we set)
// don't affect measurement.
"\(text.cacheKey),\(font.fontName),\(font.pointSize),\(textAlignment?.rawValue ?? 0)"
}
}
// MARK: -
public class CVText {
public enum MeasurementMode { case view, layoutManager }
public static var measurementQueue: DispatchQueue { CVUtils.workQueue }
private static var reuseLabels: Bool {
false
}
public static var defaultLabelMeasurementMode: MeasurementMode {
.layoutManager
}
private static var reuseTextViews: Bool {
false
}
public static var defaultTextViewMeasurementMode: MeasurementMode {
.layoutManager
}
private static var cacheMeasurements = true
private static let cacheSize: Int = 500
// MARK: - UILabel
private static let label_main = UILabel()
private static let label_workQueue = UILabel()
private static var labelForMeasurement: UILabel {
guard reuseLabels else {
return UILabel()
}
if Thread.isMainThread {
return label_main
} else {
if !CurrentAppContext().isRunningTests {
assertOnQueue(measurementQueue)
}
return label_workQueue
}
}
private static func buildCacheKey(configKey: String, maxWidth: CGFloat) -> CacheKey {
"\(configKey),\(maxWidth)"
}
private static let labelCache = LRUCache<CacheKey, CGSize>(maxSize: cacheSize)
private static let unfairLock = UnfairLock()
public static func measureLabel(mode: MeasurementMode = defaultLabelMeasurementMode, config: CVLabelConfig, maxWidth: CGFloat) -> CGSize {
unfairLock.withLock {
measureLabelLocked(mode: mode, config: config, maxWidth: maxWidth)
}
}
private static func measureLabelLocked(mode: MeasurementMode = defaultLabelMeasurementMode, config: CVLabelConfig, maxWidth: CGFloat) -> CGSize {
let cacheKey = buildCacheKey(configKey: config.cacheKey, maxWidth: maxWidth)
if cacheMeasurements,
let result = labelCache.get(key: cacheKey) {
return result
}
let result: CGSize
switch mode {
case .layoutManager:
result = measureLabelUsingLayoutManager(config: config, maxWidth: maxWidth)
case .view:
result = measureLabelUsingView(config: config, maxWidth: maxWidth)
}
owsAssertDebug(result.width > 0)
owsAssertDebug(result.height > 0)
if cacheMeasurements {
labelCache.set(key: cacheKey, value: result.ceil)
}
return result.ceil
}
private static func measureLabelUsingView(config: CVLabelConfig, maxWidth: CGFloat) -> CGSize {
let label = labelForMeasurement
config.applyForMeasurement(label: label)
var size = label.sizeThatFits(CGSize(width: maxWidth, height: CGFloat.greatestFiniteMagnitude)).ceil
// Truncate to available space if necessary.
size.width = min(size.width, maxWidth)
return size
}
private static func measureLabelUsingLayoutManager(config: CVLabelConfig, maxWidth: CGFloat) -> CGSize {
let textContainer = NSTextContainer(size: CGSize(width: maxWidth, height: .greatestFiniteMagnitude))
textContainer.maximumNumberOfLines = config.numberOfLines
textContainer.lineBreakMode = config.lineBreakMode
textContainer.lineFragmentPadding = 0
return textContainer.size(for: config.text, font: config.font)
}
// MARK: - UITextView
private static let textView_main = {
buildTextView()
}()
private static let textView_workQueue = {
buildTextView()
}()
private static var textViewForMeasurement: UITextView {
guard reuseTextViews else {
return buildTextView()
}
if Thread.isMainThread {
return textView_main
} else {
if !CurrentAppContext().isRunningTests {
assertOnQueue(measurementQueue)
}
return textView_workQueue
}
}
private static let textViewCache = LRUCache<CacheKey, CGSize>(maxSize: cacheSize)
public static func measureTextView(mode: MeasurementMode = defaultTextViewMeasurementMode,
config: CVTextViewConfig,
maxWidth: CGFloat) -> CGSize {
unfairLock.withLock {
measureTextViewLocked(mode: mode, config: config, maxWidth: maxWidth)
}
}
private static func measureTextViewLocked(mode: MeasurementMode = defaultTextViewMeasurementMode,
config: CVTextViewConfig,
maxWidth: CGFloat) -> CGSize {
let cacheKey = buildCacheKey(configKey: config.cacheKey, maxWidth: maxWidth)
if cacheMeasurements,
let result = textViewCache.get(key: cacheKey) {
return result
}
let result: CGSize
switch mode {
case .layoutManager:
result = measureTextViewUsingLayoutManager(config: config, maxWidth: maxWidth)
case .view:
result = measureTextViewUsingView(config: config, maxWidth: maxWidth)
}
owsAssertDebug(result.width > 0)
owsAssertDebug(result.height > 0)
if cacheMeasurements {
textViewCache.set(key: cacheKey, value: result.ceil)
}
return result.ceil
}
private static func measureTextViewUsingView(config: CVTextViewConfig, maxWidth: CGFloat) -> CGSize {
let textView = textViewForMeasurement
config.applyForMeasurement(textView: textView)
return textView.sizeThatFits(CGSize(width: maxWidth, height: CGFloat.greatestFiniteMagnitude)).ceil
}
private static func measureTextViewUsingLayoutManager(config: CVTextViewConfig, maxWidth: CGFloat) -> CGSize {
let textContainer = NSTextContainer(size: CGSize(width: maxWidth, height: .greatestFiniteMagnitude))
textContainer.lineFragmentPadding = 0
return textContainer.size(for: config.text, font: config.font)
}
public static func buildTextView() -> OWSMessageTextView {
let textView = OWSMessageTextView()
textView.backgroundColor = .clear
textView.isOpaque = false
textView.isEditable = false
textView.isSelectable = true
textView.textContainer.lineFragmentPadding = 0
textView.isScrollEnabled = false
textView.textContainerInset = .zero
textView.contentInset = .zero
return textView
}
}
private extension NSTextContainer {
func size(for textValue: CVTextValue, font: UIFont) -> CGSize {
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(self)
let attributedString: NSAttributedString
switch textValue {
case .attributedText(let text):
let mutableText = NSMutableAttributedString(attributedString: text)
// The original attributed string may not have an overall font
// assigned. Without it, measurement will not be correct. We
// assign a font here with "add" which will not override any
// ranges that already have a different font assigned.
mutableText.addAttributeToEntireString(.font, value: font)
attributedString = mutableText
case .text(let text):
attributedString = NSAttributedString(string: text, attributes: [.font: font])
}
// The string must be assigned to the NSTextStorage *after* it has
// an associated layout manager. Otherwise, the `NSOriginalFont`
// attribute will not be defined correctly resulting in incorrect
// measurement of character sets that font doesn't support natively
// (CJK, Arabic, Emoji, etc.)
let textStorage = NSTextStorage()
textStorage.addLayoutManager(layoutManager)
textStorage.setAttributedString(attributedString)
// The NSTextStorage object owns all the other layout components,
// so there are only weak references to it. In optimized builds,
// this can result in it being freed before we perform measurement.
// We can work around this by explicitly extending the lifetime of
// textStorage until measurement is completed.
let size = withExtendedLifetime(textStorage) { layoutManager.usedRect(for: self).size }
return size.ceil
}
}