390 lines
15 KiB
Swift
390 lines
15 KiB
Swift
import CoreText
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import UIKit
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#if canImport(DTCoreText)
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import DTCoreText
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#endif
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/// CoreText 帧工厂：负责帧创建、行级裁剪、属性查询和诊断构建。
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///
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/// 叶节点组件，被 RDEPUBChapterPageCounter 和 RDEPUBPageBreakPolicy 调用。
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struct RDEPUBCoreTextPageFrameFactory: RDEPUBPageFrameBuilding {
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let attributedString: NSAttributedString
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let pageSize: CGSize
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let config: RDEPUBTextLayoutConfig
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private let pageBreakPolicy: RDEPUBPageBreakPolicy
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init(attributedString: NSAttributedString, pageSize: CGSize, config: RDEPUBTextLayoutConfig = .default) {
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self.attributedString = attributedString
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self.pageSize = pageSize
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self.config = config
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self.pageBreakPolicy = RDEPUBPageBreakPolicy(attributedString: attributedString)
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}
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/// 协议要求的便捷初始化（使用默认配置）
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init() {
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self.init(attributedString: NSAttributedString(), pageSize: .zero, config: .default)
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}
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// MARK: - RDEPUBPageFrameBuilding 协议
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func makeFrames(
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attributedString: NSAttributedString,
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pageSize: CGSize,
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config: RDEPUBTextLayoutConfig,
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fragmentOffsets: [String: Int]
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) -> [RDEPUBTextLayoutFrame] {
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let factory = RDEPUBCoreTextPageFrameFactory(attributedString: attributedString, pageSize: pageSize, config: config)
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let counter = RDEPUBChapterPageCounter(factory: factory)
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return counter.layoutFrames(fragmentOffsets: fragmentOffsets)
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}
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// MARK: - 帧构建
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/// 从列矩形构建 CGPath（用于 CTFramesetterCreateFrame）。
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static func makeLayoutPath(pageSize: CGSize, config: RDEPUBTextLayoutConfig) -> CGPath {
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let columnRects = config.columnRects(fallback: pageSize)
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guard columnRects.count > 1 else {
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return CGPath(rect: columnRects.first ?? CGRect(origin: .zero, size: pageSize), transform: nil)
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}
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let path = CGMutablePath()
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for rect in columnRects {
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path.addRect(rect)
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}
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return path
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}
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// MARK: - 行级裁剪
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/// 从 CTFrame 最后一行向前扫描，移除落在 avoidPageBreakInside 保护块内的尾部行。
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func trimmedRangeForAvoidPageBreakInside(
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from frame: CTFrame,
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proposed: NSRange
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) -> NSRange {
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guard config.avoidPageBreakInsideEnabled else { return proposed }
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let lines = CTFrameGetLines(frame) as! [CTLine]
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guard !lines.isEmpty else { return proposed }
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let lineRanges = lines.map {
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let range = CTLineGetStringRange($0)
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return NSRange(location: range.location, length: range.length)
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}
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return trimmedRangeForAvoidPageBreakInside(proposed: proposed, lineRanges: lineRanges)
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}
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/// CoreText 路径的 keepWithNext 处理：从最后行向前扫描
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func trimmedRangeForKeepWithNext(
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from frame: CTFrame,
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proposed: NSRange
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) -> NSRange {
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let lines = CTFrameGetLines(frame) as! [CTLine]
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let lineRanges = lines.map {
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let range = CTLineGetStringRange($0)
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return NSRange(location: range.location, length: range.length)
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}
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return trimmedRangeForKeepWithNext(proposed: proposed, lineRanges: lineRanges)
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}
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#if canImport(DTCoreText)
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/// DTCoreText 路径的 avoidPageBreakInside 处理
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func trimmedRangeForAvoidPageBreakInside(
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from layoutFrame: DTCoreTextLayoutFrame,
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proposed: NSRange
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) -> NSRange {
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guard config.avoidPageBreakInsideEnabled else { return proposed }
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guard let lines = layoutFrame.lines as? [DTCoreTextLayoutLine], !lines.isEmpty else {
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return proposed
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}
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let lineRanges = lines.map { $0.stringRange() }
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return trimmedRangeForAvoidPageBreakInside(proposed: proposed, lineRanges: lineRanges)
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}
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/// DTCoreText 路径的 keepWithNext 处理
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func trimmedRangeForKeepWithNext(
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from layoutFrame: DTCoreTextLayoutFrame,
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proposed: NSRange
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) -> NSRange {
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guard let lines = layoutFrame.lines as? [DTCoreTextLayoutLine], !lines.isEmpty else {
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return proposed
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}
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let lineRanges = lines.map { $0.stringRange() }
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return trimmedRangeForKeepWithNext(proposed: proposed, lineRanges: lineRanges)
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}
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#endif
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/// 从最后行向前扫描，移除落在 avoidPageBreakInside 保护块内的尾部行（通用路径）。
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func trimmedRangeForAvoidPageBreakInside(
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proposed: NSRange,
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lineRanges: [NSRange]
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) -> NSRange {
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guard config.avoidPageBreakInsideEnabled, !lineRanges.isEmpty else { return proposed }
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let kMaxLinesToRemove = 3
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var linesToRemove = 0
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for lineRange in lineRanges.reversed() {
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if pageBreakPolicy.lineIsInAvoidPageBreakInsideBlock(lineRange) {
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linesToRemove += 1
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if linesToRemove >= kMaxLinesToRemove {
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linesToRemove = kMaxLinesToRemove
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break
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}
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} else {
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break
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}
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}
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guard linesToRemove > 0 else { return proposed }
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let validLineCount = lineRanges.count - linesToRemove
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guard validLineCount > 0 else { return proposed }
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let lastValidLine = lineRanges[validLineCount - 1]
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let endLocation = lastValidLine.location + lastValidLine.length
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let adjustedLength = endLocation - proposed.location
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guard adjustedLength > 0 else { return proposed }
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return NSRange(location: proposed.location, length: adjustedLength)
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}
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/// 从最后行向前扫描，移除落在 keepWithNext 保护块内的尾部行。
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func trimmedRangeForKeepWithNext(
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proposed: NSRange,
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lineRanges: [NSRange]
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) -> NSRange {
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guard !lineRanges.isEmpty else { return proposed }
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let kMaxLinesToRemove = 3
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var linesToRemove = 0
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for lineRange in lineRanges.reversed() {
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if pageBreakPolicy.lineIsInKeepWithNextBlock(lineRange) {
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linesToRemove += 1
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if linesToRemove >= kMaxLinesToRemove {
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linesToRemove = kMaxLinesToRemove
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break
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}
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} else {
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break
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}
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}
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guard linesToRemove > 0 else { return proposed }
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let validLineCount = lineRanges.count - linesToRemove
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guard validLineCount > 0 else { return proposed }
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let lastValidLine = lineRanges[validLineCount - 1]
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let endLocation = lastValidLine.location + lastValidLine.length
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let adjustedLength = endLocation - proposed.location
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guard adjustedLength > 0 else { return proposed }
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return NSRange(location: proposed.location, length: adjustedLength)
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}
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// MARK: - 行信息提取
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/// 获取 CTFrame 中所有行的字符范围
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static func lineRanges(from frame: CTFrame) -> [NSRange] {
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let lines = CTFrameGetLines(frame) as! [CTLine]
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return lines.map {
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let lineRange = CTLineGetStringRange($0)
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return NSRange(location: lineRange.location, length: lineRange.length)
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}
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}
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#if canImport(DTCoreText)
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/// 获取 DTCoreTextLayoutFrame 中所有行的字符范围
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static func lineRanges(from layoutFrame: DTCoreTextLayoutFrame) -> [NSRange] {
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guard let lines = layoutFrame.lines as? [DTCoreTextLayoutLine] else {
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return []
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}
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return lines.map { $0.stringRange() }
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}
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#endif
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// MARK: - 属性查询
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/// 获取指定位置的块级元素范围
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func blockRange(at location: Int) -> NSRange? {
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guard location >= 0, location < attributedString.length else { return nil }
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let attributes = attributedString.attributes(at: location, effectiveRange: nil)
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if let encodedRange = attributes[.rdPageBlockRange] as? String {
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return NSRangeFromString(encodedRange)
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}
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return nil
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}
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/// 获取指定位置的块级元素类型
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func blockKind(at location: Int) -> RDEPUBTextBlockKind? {
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guard location >= 0, location < attributedString.length else { return nil }
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let attributes = attributedString.attributes(at: location, effectiveRange: nil)
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guard let rawValue = attributes[.rdPageBlockKind] as? String else { return nil }
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return RDEPUBTextBlockKind(rawValue: rawValue)
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}
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/// 获取指定位置的附件布局方式
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func attachmentPlacement(at location: Int) -> RDEPUBTextAttachmentPlacement? {
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guard location >= 0, location < attributedString.length else { return nil }
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let attributes = attributedString.attributes(at: location, effectiveRange: nil)
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guard let rawValue = attributes[.rdPageAttachmentPlacement] as? String else { return nil }
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return RDEPUBTextAttachmentPlacement(rawValue: rawValue)
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}
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/// 获取包含指定位置的段落范围
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func paragraphRange(containing location: Int) -> NSRange {
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let source = attributedString.string as NSString
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guard source.length > 0 else { return NSRange(location: 0, length: 0) }
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let safeLocation = min(max(location, 0), max(source.length - 1, 0))
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return source.paragraphRange(for: NSRange(location: safeLocation, length: 0))
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}
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/// 获取指定范围内的所有附件字符范围
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func attachmentRanges(in range: NSRange) -> [NSRange] {
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guard let safeRange = clampedRange(range), safeRange.length > 0 else {
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return []
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}
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var results: [NSRange] = []
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attributedString.enumerateAttribute(.rdPageAttachmentKind, in: safeRange) { value, attributeRange, _ in
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guard value != nil else { return }
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results.append(attributeRange)
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}
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return results
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}
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/// 获取指定位置的语义提示列表
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func semanticHints(at location: Int) -> [RDEPUBTextSemanticHint] {
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guard location >= 0, location < attributedString.length else { return [] }
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let attributes = attributedString.attributes(at: location, effectiveRange: nil)
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guard let rawValue = attributes[.rdPageSemanticHints] as? String else { return [] }
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return rawValue
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.split(separator: ",")
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.compactMap { RDEPUBTextSemanticHint(rawValue: String($0)) }
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}
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/// 获取指定范围内的附件类型列表（去重）
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func attachmentKinds(in range: NSRange) -> [RDEPUBTextAttachmentKind] {
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guard let safeRange = clampedRange(range), safeRange.length > 0 else {
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return []
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}
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var kinds: [RDEPUBTextAttachmentKind] = []
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attributedString.enumerateAttribute(.rdPageAttachmentKind, in: safeRange) { value, _, _ in
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guard let rawValue = value as? String,
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let kind = RDEPUBTextAttachmentKind(rawValue: rawValue),
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!kinds.contains(kind) else {
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return
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}
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kinds.append(kind)
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}
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return kinds
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}
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/// 获取指定范围内的块级元素类型列表（去重）
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func blockKinds(in range: NSRange) -> [RDEPUBTextBlockKind] {
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guard let safeRange = clampedRange(range), safeRange.length > 0 else {
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return []
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}
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var kinds: [RDEPUBTextBlockKind] = []
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attributedString.enumerateAttribute(.rdPageBlockKind, in: safeRange) { value, _, _ in
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guard let rawValue = value as? String,
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let kind = RDEPUBTextBlockKind(rawValue: rawValue),
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!kinds.contains(kind) else {
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return
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}
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kinds.append(kind)
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}
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return kinds
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}
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/// 获取指定范围内的语义提示列表（去重）
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func semanticHints(in range: NSRange) -> [RDEPUBTextSemanticHint] {
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guard let safeRange = clampedRange(range), safeRange.length > 0 else {
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return []
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}
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var hints: [RDEPUBTextSemanticHint] = []
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attributedString.enumerateAttribute(.rdPageSemanticHints, in: safeRange) { value, _, _ in
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guard let rawValue = value as? String else { return }
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for hint in rawValue.split(separator: ",").compactMap({ RDEPUBTextSemanticHint(rawValue: String($0)) }) where !hints.contains(hint) {
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hints.append(hint)
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}
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}
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return hints
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}
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/// 获取指定范围内的附件布局方式列表（去重）
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func attachmentPlacements(in range: NSRange) -> [RDEPUBTextAttachmentPlacement] {
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guard let safeRange = clampedRange(range), safeRange.length > 0 else {
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return []
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}
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var placements: [RDEPUBTextAttachmentPlacement] = []
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attributedString.enumerateAttribute(.rdPageAttachmentPlacement, in: safeRange) { value, _, _ in
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guard let rawValue = value as? String,
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let placement = RDEPUBTextAttachmentPlacement(rawValue: rawValue),
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!placements.contains(placement) else {
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return
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}
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placements.append(placement)
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}
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return placements
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}
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/// 将范围裁剪到 attributedString 的合法边界内。
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func clampedRange(_ range: NSRange) -> NSRange? {
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guard range.location >= 0, range.length >= 0 else { return nil }
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guard attributedString.length > 0 else {
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return range.location == 0 ? NSRange(location: 0, length: 0) : nil
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}
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guard range.location < attributedString.length else { return nil }
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let maxLength = attributedString.length - range.location
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return NSRange(location: range.location, length: min(range.length, maxLength))
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}
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/// 查找指定位置之前最近的 fragment ID（用于阅读位置恢复）
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func nearestTrailingFragmentID(
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endingAt location: Int,
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fragmentOffsets: [String: Int]
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) -> String? {
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fragmentOffsets
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.filter { $0.value <= location }
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.max { lhs, rhs in lhs.value < rhs.value }?
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.key
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}
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// MARK: - 诊断日志
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/// 生成分页诊断日志
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func diagnostics(
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reason: RDEPUBTextPageBreakReason,
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range: NSRange,
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attachmentRanges: [NSRange],
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blockRange: NSRange?,
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blockKinds: [RDEPUBTextBlockKind],
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semanticHints: [RDEPUBTextSemanticHint],
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attachmentPlacements: [RDEPUBTextAttachmentPlacement],
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trigger: String? = nil
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) -> [String] {
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var items = ["page break: \(reason.rawValue)", "page range: \(NSStringFromRange(range))"]
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if let blockRange {
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items.append("block range: \(NSStringFromRange(blockRange))")
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}
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if !attachmentRanges.isEmpty {
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items.append("attachment ranges: \(attachmentRanges.map(NSStringFromRange).joined(separator: ","))")
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}
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if !blockKinds.isEmpty {
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items.append("block kinds: \(blockKinds.map(\.rawValue).joined(separator: ","))")
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}
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if !semanticHints.isEmpty {
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items.append("semantic hints: \(semanticHints.map(\.rawValue).joined(separator: ","))")
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}
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if !attachmentPlacements.isEmpty {
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items.append("attachment placements: \(attachmentPlacements.map(\.rawValue).joined(separator: ","))")
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}
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if let trigger, !trigger.isEmpty {
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items.append("semantic trigger: \(trigger)")
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}
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return items
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}
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}
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