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Peter
293
TelegramUI/TextNode.swift
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293
TelegramUI/TextNode.swift
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import Foundation
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import AsyncDisplayKit
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import Display
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private let defaultFont = UIFont.systemFont(ofSize: 15.0)
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private final class TextNodeLine {
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let line: CTLine
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let frame: CGRect
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init(line: CTLine, frame: CGRect) {
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self.line = line
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self.frame = frame
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}
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}
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enum TextNodeCutoutPosition {
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case TopLeft
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case TopRight
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}
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struct TextNodeCutout: Equatable {
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let position: TextNodeCutoutPosition
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let size: CGSize
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}
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func ==(lhs: TextNodeCutout, rhs: TextNodeCutout) -> Bool {
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return lhs.position == rhs.position && lhs.size == rhs.size
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}
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final class TextNodeLayout: NSObject {
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fileprivate let attributedString: NSAttributedString?
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fileprivate let maximumNumberOfLines: Int
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fileprivate let truncationType: CTLineTruncationType
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fileprivate let backgroundColor: UIColor?
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fileprivate let constrainedSize: CGSize
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fileprivate let cutout: TextNodeCutout?
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let size: CGSize
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fileprivate let lines: [TextNodeLine]
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fileprivate init(attributedString: NSAttributedString?, maximumNumberOfLines: Int, truncationType: CTLineTruncationType, constrainedSize: CGSize, cutout: TextNodeCutout?, size: CGSize, lines: [TextNodeLine], backgroundColor: UIColor?) {
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self.attributedString = attributedString
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self.maximumNumberOfLines = maximumNumberOfLines
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self.truncationType = truncationType
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self.constrainedSize = constrainedSize
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self.cutout = cutout
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self.size = size
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self.lines = lines
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self.backgroundColor = backgroundColor
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}
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var numberOfLines: Int {
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return self.lines.count
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}
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var trailingLineWidth: CGFloat {
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if let lastLine = self.lines.last {
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return lastLine.frame.width
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} else {
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return 0.0
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}
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}
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}
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final class TextNode: ASDisplayNode {
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private var cachedLayout: TextNodeLayout?
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override init() {
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super.init()
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self.backgroundColor = UIColor.clear
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self.isOpaque = false
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self.clipsToBounds = false
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}
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private class func calculateLayout(attributedString: NSAttributedString?, maximumNumberOfLines: Int, truncationType: CTLineTruncationType, backgroundColor: UIColor?, constrainedSize: CGSize, cutout: TextNodeCutout?) -> TextNodeLayout {
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if let attributedString = attributedString {
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let font: CTFont
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if attributedString.length != 0 {
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if let stringFont = attributedString.attribute(kCTFontAttributeName as String, at: 0, effectiveRange: nil) {
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font = stringFont as! CTFont
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} else {
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font = defaultFont
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}
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} else {
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font = defaultFont
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}
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let fontAscent = CTFontGetAscent(font)
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let fontDescent = CTFontGetDescent(font)
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let fontLineHeight = floor(fontAscent + fontDescent)
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let fontLineSpacing = floor(fontLineHeight * 0.12)
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var lines: [TextNodeLine] = []
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var maybeTypesetter: CTTypesetter?
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maybeTypesetter = CTTypesetterCreateWithAttributedString(attributedString as CFAttributedString)
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if maybeTypesetter == nil {
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return TextNodeLayout(attributedString: attributedString, maximumNumberOfLines: maximumNumberOfLines, truncationType: truncationType, constrainedSize: constrainedSize, cutout: cutout, size: CGSize(), lines: [], backgroundColor: backgroundColor)
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}
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let typesetter = maybeTypesetter!
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var lastLineCharacterIndex: CFIndex = 0
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var layoutSize = CGSize()
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var cutoutEnabled = false
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var cutoutMinY: CGFloat = 0.0
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var cutoutMaxY: CGFloat = 0.0
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var cutoutWidth: CGFloat = 0.0
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var cutoutOffset: CGFloat = 0.0
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if let cutout = cutout {
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cutoutMinY = -fontLineSpacing
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cutoutMaxY = cutout.size.height + fontLineSpacing
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cutoutWidth = cutout.size.width
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if case .TopLeft = cutout.position {
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cutoutOffset = cutoutWidth
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}
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cutoutEnabled = true
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}
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var first = true
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while true {
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var lineConstrainedWidth = constrainedSize.width
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var lineOriginY = floorToScreenPixels(layoutSize.height + fontLineHeight - fontLineSpacing * 2.0)
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if !first {
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lineOriginY += fontLineSpacing
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}
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var lineCutoutOffset: CGFloat = 0.0
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var lineAdditionalWidth: CGFloat = 0.0
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if cutoutEnabled {
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if lineOriginY < cutoutMaxY && lineOriginY + fontLineHeight > cutoutMinY {
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lineConstrainedWidth = max(1.0, lineConstrainedWidth - cutoutWidth)
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lineCutoutOffset = cutoutOffset
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lineAdditionalWidth = cutoutWidth
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}
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}
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let lineCharacterCount = CTTypesetterSuggestLineBreak(typesetter, lastLineCharacterIndex, Double(lineConstrainedWidth))
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if maximumNumberOfLines != 0 && lines.count == maximumNumberOfLines - 1 && lineCharacterCount > 0 {
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if first {
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first = false
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} else {
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layoutSize.height += fontLineSpacing
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}
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let coreTextLine: CTLine
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let originalLine = CTTypesetterCreateLineWithOffset(typesetter, CFRange(location: lastLineCharacterIndex, length: attributedString.length - lastLineCharacterIndex), 0.0)
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if CTLineGetTypographicBounds(originalLine, nil, nil, nil) - CTLineGetTrailingWhitespaceWidth(originalLine) < Double(constrainedSize.width) {
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coreTextLine = originalLine
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} else {
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var truncationTokenAttributes: [String : AnyObject] = [:]
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truncationTokenAttributes[kCTFontAttributeName as String] = font
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truncationTokenAttributes[kCTForegroundColorFromContextAttributeName as String] = true as NSNumber
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let tokenString = "\u{2026}"
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let truncatedTokenString = NSAttributedString(string: tokenString, attributes: truncationTokenAttributes)
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let truncationToken = CTLineCreateWithAttributedString(truncatedTokenString)
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coreTextLine = CTLineCreateTruncatedLine(originalLine, Double(constrainedSize.width), truncationType, truncationToken) ?? truncationToken
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}
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let lineWidth = ceil(CGFloat(CTLineGetTypographicBounds(coreTextLine, nil, nil, nil) - CTLineGetTrailingWhitespaceWidth(coreTextLine)))
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let lineFrame = CGRect(x: lineCutoutOffset, y: lineOriginY, width: lineWidth, height: fontLineHeight)
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layoutSize.height += fontLineHeight + fontLineSpacing
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layoutSize.width = max(layoutSize.width, lineWidth + lineAdditionalWidth)
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lines.append(TextNodeLine(line: coreTextLine, frame: lineFrame))
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break
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} else {
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if lineCharacterCount > 0 {
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if first {
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first = false
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} else {
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layoutSize.height += fontLineSpacing
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}
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let coreTextLine = CTTypesetterCreateLineWithOffset(typesetter, CFRangeMake(lastLineCharacterIndex, lineCharacterCount), 100.0)
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lastLineCharacterIndex += lineCharacterCount
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let lineWidth = ceil(CGFloat(CTLineGetTypographicBounds(coreTextLine, nil, nil, nil) - CTLineGetTrailingWhitespaceWidth(coreTextLine)))
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let lineFrame = CGRect(x: lineCutoutOffset, y: lineOriginY, width: lineWidth, height: fontLineHeight)
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layoutSize.height += fontLineHeight
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layoutSize.width = max(layoutSize.width, lineWidth + lineAdditionalWidth)
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lines.append(TextNodeLine(line: coreTextLine, frame: lineFrame))
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} else {
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if !lines.isEmpty {
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layoutSize.height += fontLineSpacing
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}
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break
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}
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}
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}
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return TextNodeLayout(attributedString: attributedString, maximumNumberOfLines: maximumNumberOfLines, truncationType: truncationType, constrainedSize: constrainedSize, cutout: cutout, size: CGSize(width: ceil(layoutSize.width), height: ceil(layoutSize.height)), lines: lines, backgroundColor: backgroundColor)
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} else {
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return TextNodeLayout(attributedString: attributedString, maximumNumberOfLines: maximumNumberOfLines, truncationType: truncationType, constrainedSize: constrainedSize, cutout: cutout, size: CGSize(), lines: [], backgroundColor: backgroundColor)
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}
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}
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override func drawParameters(forAsyncLayer layer: _ASDisplayLayer) -> NSObjectProtocol? {
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return self.cachedLayout
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}
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@objc override class func draw(_ bounds: CGRect, withParameters parameters: NSObjectProtocol!, isCancelled: asdisplaynode_iscancelled_block_t, isRasterizing: Bool) {
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let context = UIGraphicsGetCurrentContext()!
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context.setAllowsAntialiasing(true)
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context.setAllowsFontSmoothing(false)
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context.setShouldSmoothFonts(false)
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context.setAllowsFontSubpixelPositioning(false)
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context.setShouldSubpixelPositionFonts(false)
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context.setAllowsFontSubpixelQuantization(true)
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context.setShouldSubpixelQuantizeFonts(true)
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if let layout = parameters as? TextNodeLayout {
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if !isRasterizing || layout.backgroundColor != nil {
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context.setBlendMode(.copy)
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context.setFillColor((layout.backgroundColor ?? UIColor.clear).cgColor)
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context.fill(bounds)
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}
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let textMatrix = context.textMatrix
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let textPosition = context.textPosition
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//CGContextSaveGState(context)
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context.textMatrix = CGAffineTransform(scaleX: 1.0, y: -1.0)
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//let clipRect = CGContextGetClipBoundingBox(context)
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for i in 0 ..< layout.lines.count {
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let line = layout.lines[i]
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context.textPosition = CGPoint(x: line.frame.origin.x, y: line.frame.origin.y)
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CTLineDraw(line.line, context)
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}
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//CGContextRestoreGState(context)
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context.textMatrix = textMatrix
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context.textPosition = CGPoint(x: textPosition.x, y: textPosition.y)
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}
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context.setBlendMode(.normal)
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}
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class func asyncLayout(_ maybeNode: TextNode?) -> (_ attributedString: NSAttributedString?, _ backgroundColor: UIColor?, _ maximumNumberOfLines: Int, _ truncationType: CTLineTruncationType, _ constrainedSize: CGSize, _ cutout: TextNodeCutout?) -> (TextNodeLayout, () -> TextNode) {
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let existingLayout: TextNodeLayout? = maybeNode?.cachedLayout
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return { attributedString, backgroundColor, maximumNumberOfLines, truncationType, constrainedSize, cutout in
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let layout: TextNodeLayout
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var updated = false
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if let existingLayout = existingLayout, existingLayout.constrainedSize == constrainedSize && existingLayout.maximumNumberOfLines == maximumNumberOfLines && existingLayout.truncationType == truncationType && existingLayout.cutout == cutout {
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let stringMatch: Bool
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if let existingString = existingLayout.attributedString, let string = attributedString {
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stringMatch = existingString.isEqual(to: string)
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} else if existingLayout.attributedString == nil && attributedString == nil {
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stringMatch = true
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} else {
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stringMatch = false
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}
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if stringMatch {
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layout = existingLayout
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} else {
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layout = TextNode.calculateLayout(attributedString: attributedString, maximumNumberOfLines: maximumNumberOfLines, truncationType: truncationType, backgroundColor: backgroundColor, constrainedSize: constrainedSize, cutout: cutout)
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updated = true
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}
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} else {
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layout = TextNode.calculateLayout(attributedString: attributedString, maximumNumberOfLines: maximumNumberOfLines, truncationType: truncationType, backgroundColor: backgroundColor, constrainedSize: constrainedSize, cutout: cutout)
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updated = true
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}
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let node = maybeNode ?? TextNode()
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return (layout, {
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node.cachedLayout = layout
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if updated {
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node.setNeedsDisplay()
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}
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return node
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})
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}
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}
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}
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