Signal-iOS/SignalMessaging/Views/CVText.swift
2020-12-11 16:33:38 -03:00

635 lines
21 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 containsCJKCharacters: Bool
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.containsCJKCharacters = text.containsCJKCharacters
if containsCJKCharacters {
self.font = font.cjkCompatibleVariant
} else {
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.containsCJKCharacters = attributedText.string.containsCJKCharacters
if containsCJKCharacters {
self.text = .attributedText(attributedText: attributedText.withCJKCompatibleFonts)
self.font = font.cjkCompatibleVariant
} else {
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 containsCJKCharacters: Bool
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.containsCJKCharacters = text.containsCJKCharacters
if containsCJKCharacters {
self.font = font.cjkCompatibleVariant
} else {
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.containsCJKCharacters = attributedText.string.containsCJKCharacters
if containsCJKCharacters {
self.text = .attributedText(attributedText: attributedText.withCJKCompatibleFonts)
self.font = font.cjkCompatibleVariant
} else {
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, boundingRect }
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)
public static func measureLabel(mode: MeasurementMode = defaultLabelMeasurementMode, config: CVLabelConfig, maxWidth: CGFloat) -> CGSize {
if !CurrentAppContext().isRunningTests {
assertOnQueue(measurementQueue)
}
let cacheKey = buildCacheKey(configKey: config.cacheKey, maxWidth: maxWidth)
if cacheMeasurements,
let result = labelCache.get(key: cacheKey) {
return result
}
let result: CGSize
switch mode {
case .boundingRect:
result = measureLabelUsingBoundingRect(config: config, maxWidth: maxWidth)
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 textStorage: NSTextStorage
switch config.text {
case .attributedText(let text):
textStorage = NSTextStorage(attributedString: text)
case .text(let text):
textStorage = NSTextStorage(string: text)
}
textStorage.addAttribute(.font, value: config.font, range: textStorage.entireRange)
let textContainer = NSTextContainer(size: CGSize(width: maxWidth, height: .greatestFiniteMagnitude))
textContainer.maximumNumberOfLines = config.numberOfLines
textContainer.lineBreakMode = config.lineBreakMode
textContainer.lineFragmentPadding = 0
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
let size = layoutManager.usedRect(for: textContainer).size
// For some reason, in production builds, the textStorage
// seems to get optimized out in many circumstances. This
// results in `usedRect` measuring an empty string and a
// size of 0,0.
// TODO: Figure out a better way to fix this. For now,
// by just using the textStorage later it ensures that it
// is properly measured.
_ = textStorage
return size.ceil
}
private static func measureLabelUsingBoundingRect(config: CVLabelConfig, maxWidth: CGFloat) -> CGSize {
let attributedText: NSMutableAttributedString
switch config.text {
case .attributedText(let text):
attributedText = NSMutableAttributedString(attributedString: text)
case .text(let text):
attributedText = NSMutableAttributedString(string: text)
}
attributedText.addAttribute(.font, value: config.font, range: attributedText.entireRange)
let maxHeight: CGFloat
if config.numberOfLines > 0 {
maxHeight = config.font.lineHeight * CGFloat(config.numberOfLines)
} else {
maxHeight = .greatestFiniteMagnitude
}
var size = attributedText.boundingRect(
with: CGSize(width: maxWidth, height: .greatestFiniteMagnitude),
options: [.usesLineFragmentOrigin, .usesFontLeading],
context: nil
).size
// We can't pass max height to the measurement, because it results
// in the final width being way off.
size.height = min(maxHeight, size.height)
owsAssertDebug(size.width <= maxWidth)
return size.ceil
}
// 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 {
if !CurrentAppContext().isRunningTests {
assertOnQueue(measurementQueue)
}
let cacheKey = buildCacheKey(configKey: config.cacheKey, maxWidth: maxWidth)
if cacheMeasurements,
let result = textViewCache.get(key: cacheKey) {
return result
}
let result: CGSize
switch mode {
case .boundingRect:
result = measureTextViewUsingBoundingRect(config: config, maxWidth: maxWidth)
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 textStorage: NSTextStorage
switch config.text {
case .attributedText(let text):
textStorage = NSTextStorage(attributedString: text)
case .text(let text):
textStorage = NSTextStorage(string: text)
}
textStorage.addAttribute(.font, value: config.font, range: textStorage.entireRange)
let textContainer = NSTextContainer(size: CGSize(width: maxWidth, height: .greatestFiniteMagnitude))
textContainer.lineFragmentPadding = 0
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainer)
textStorage.addLayoutManager(layoutManager)
let size = layoutManager.usedRect(for: textContainer).size
// For some reason, in production builds, the textStorage
// seems to get optimized out in many circumstances. This
// results in `usedRect` measuring an empty string and a
// size of 0,0.
// TODO: Figure out a better way to fix this. For now,
// by just using the textStorage later it ensures that it
// is properly measured.
_ = textStorage
return size.ceil
}
private static func measureTextViewUsingBoundingRect(config: CVTextViewConfig, maxWidth: CGFloat) -> CGSize {
let attributedText: NSMutableAttributedString
switch config.text {
case .attributedText(let text):
attributedText = NSMutableAttributedString(attributedString: text)
case .text(let text):
attributedText = NSMutableAttributedString(string: text)
}
attributedText.addAttribute(.font, value: config.font, range: attributedText.entireRange)
// TODO: We might need to do something with linkTextAttributes, but in
// general since these don't have an impact on line height hopefully it
// should be unnecessary.
// In order to match `sizeThatFits` semantics on UITextView, we have to
// do some adjustments to the bounding box we try and measure in. Note,
// this will break if we change certain parameters of the UITextView
// like the textContainerInset or the contentInset. Right now we don't
// allow changing those paramters (they're hard coded in `buildTextView`)
// so we should be safe, but if that were ever to change we'd need to
// re-evaluate this measurement strategy. Ideally, we'd get these numbers
// from UIKit directly, but I have not found any good way to find them.
// If things don't work on certain iOS versions, this is also almost
// certainly the culprit (tested on iOS 13 + iOS 14 so far)
let textViewHeightAdjustment: CGFloat
if #available(iOS 14, *) {
textViewHeightAdjustment = 1
} else {
textViewHeightAdjustment = 1.7
}
var size = attributedText.boundingRect(
with: CGSize(width: maxWidth, height: CGFloat.greatestFiniteMagnitude),
options: [.usesLineFragmentOrigin],
context: nil
).size
size.height += textViewHeightAdjustment
owsAssertDebug(size.width <= maxWidth)
return size.ceil
}
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 String {
// TODO: Figure out if this check is too expensive to do
// as frequently as we are. It seems okay in initial examination.
var containsCJKCharacters: Bool {
range(of: "\\p{Han}", options: .regularExpression) != nil
}
}
private extension NSAttributedString {
var withCJKCompatibleFonts: NSAttributedString {
let mutableAttributedString = NSMutableAttributedString(attributedString: self)
mutableAttributedString.enumerateAttribute(
.font,
in: mutableAttributedString.entireRange,
options: []
) { font, subrange, _ in
guard let font = font as? UIFont else { return }
mutableAttributedString.addAttribute(
.font,
value: font.cjkCompatibleVariant,
range: subrange
)
}
return NSAttributedString(attributedString: mutableAttributedString)
}
}
private extension UIFont {
// The San Francisco font (as of iOS 14) does not allow for correct
// measurement of CJK characters. In order to work around this, when
// a string is detected to contain a CJK character we replace its font
// with HelveticaNeue, which handles measurement correctly.
// For more details see: http://www.openradar.me/43337516
var cjkCompatibleVariant: UIFont {
guard let weight = fontDescriptor.object(forKey: .face) as? String else {
owsFailDebug("Missing font weight for font \(self)")
return self
}
let replacementFontName: String
switch weight {
case "Regular": replacementFontName = "HelveticaNeue"
case "Regular Italic": replacementFontName = "HelveticaNeue-Italic"
case "Semibold": replacementFontName = "HelveticaNeue-Medium"
default: replacementFontName = "HelveticaNeue-\(weight.replacingOccurrences(of: " ", with: ""))"
}
guard let replacementFont = UIFont(name: replacementFontName, size: pointSize) else {
owsFailDebug("Missing cjk compatible font for name \(replacementFontName)")
return self
}
return replacementFont
}
}