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Enhance block ID handling in STMarkdownStreamingTextView
- Updated logic to handle cases where the block ID attribute is missing, allowing for custom renderers without STMarkdown metadata. - Improved clarity by separating the raw block ID retrieval and validation steps, ensuring more robust handling of attributed text.
1 parent 050ab10 commit 9fa7443

7 files changed

Lines changed: 572 additions & 3 deletions

‎Sources/STMarkdown/Rendering/STMarkdownBlockLayoutCalculator.swift‎

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//
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// STMarkdownBlockLayoutCalculator.swift
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// STBaseProject
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//
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import UIKit
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/// 块间距与 `NSAttributedString` 分隔符计算工具。
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///
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/// 所有方法均为纯函数，无副作用，可静态调用。
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/// 宿主（如 `NativeMarkdownView`）不再需要在内部维护等效逻辑。
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public enum STMarkdownBlockLayoutCalculator {
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// MARK: - Block Spacing
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/// 两个相邻块之间的视觉间距（点）。
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public static func spacing(
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after previousBlock: STMarkdownRenderBlock,
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before nextBlock: STMarkdownRenderBlock,
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style: STMarkdownStyle
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) -> CGFloat {
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if case .heading = nextBlock {
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// Heading 的 paragraphSpacingBefore/paragraphSpacing 已编码了上下留白，
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// 分隔符 "\n" 只是终止上一段，minimumLineHeight 对此无视觉效果，取最小值 1pt。
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return 1
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}
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if isListBridgeStrongParagraph(previousBlock: previousBlock, nextBlock: nextBlock, style: style) {
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return max(style.listItemSpacing, 1)
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}
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let prev = trailingSpacing(for: previousBlock, style: style)
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let next = leadingSpacing(for: nextBlock, style: style)
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return max(max(prev, next), 1)
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}
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/// 块之前的推荐前导间距。
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public static func leadingSpacing(for block: STMarkdownRenderBlock, style: STMarkdownStyle) -> CGFloat {
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switch block {
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case .heading(_, level: let level, anchorId: _, content: _):
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return STMarkdownTypography.headingInsets(for: level).top
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case .list:
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return style.listItemSpacing
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case .quote:
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return style.blockSpacing * 0.8
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case .codeBlock, .table, .mathBlock, .image, .thematicBreak, .details, .rawHTML:
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return style.blockSpacing
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case .paragraph:
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return style.blockSpacing
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}
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}
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/// 块之后的推荐尾随间距。
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public static func trailingSpacing(for block: STMarkdownRenderBlock, style: STMarkdownStyle) -> CGFloat {
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switch block {
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case .heading(_, level: let level, anchorId: _, content: _):
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if let bottomSpacings = style.headingBottomSpacing,
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level >= 1, level <= bottomSpacings.count {
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return bottomSpacings[level - 1]
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}
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return STMarkdownTypography.headingInsets(for: level).bottom
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case .list:
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return style.listItemSpacing
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case .quote:
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return style.blockSpacing * 0.8
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case .codeBlock, .table, .mathBlock, .image, .thematicBreak, .details, .rawHTML:
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return style.blockSpacing
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case .paragraph:
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return style.blockSpacing
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}
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}
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// MARK: - Separator AttributedString
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/// 生成两个相邻块之间的间距 `NSAttributedString`（单个 `"\n"`，行高 = 计算所得间距）。
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///
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/// - Parameters:
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/// - skipFadeInKey: 可选的"跳过淡入"自定义属性 key（流式 shimmer 用），传 nil 则不写入。
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public static func separatorAttributedString(
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after previousBlock: STMarkdownRenderBlock,
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before nextBlock: STMarkdownRenderBlock,
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style: STMarkdownStyle,
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skipFadeInKey: NSAttributedString.Key? = nil
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) -> NSAttributedString {
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let spacing = Self.spacing(after: previousBlock, before: nextBlock, style: style)
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let paragraphStyle = NSMutableParagraphStyle()
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paragraphStyle.minimumLineHeight = spacing
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paragraphStyle.maximumLineHeight = spacing
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paragraphStyle.lineBreakMode = .byWordWrapping
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var attrs: [NSAttributedString.Key: Any] = [
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.font: style.font,
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.foregroundColor: UIColor.clear,
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.paragraphStyle: paragraphStyle,
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]
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if let key = skipFadeInKey { attrs[key] = true }
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return NSAttributedString(string: "\n", attributes: attrs)
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}
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// MARK: - Block Classification Helpers
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/// 前后块是否构成"列表 ↔ standalone-strong 段落"的桥接关系（使用 listItemSpacing 而非 blockSpacing）。
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public static func isListBridgeStrongParagraph(
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previousBlock: STMarkdownRenderBlock,
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nextBlock: STMarkdownRenderBlock,
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style: STMarkdownStyle
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) -> Bool {
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(isListBlock(previousBlock) && isStandaloneStrongParagraph(nextBlock))
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|| (isStandaloneStrongParagraph(previousBlock) && isListBlock(nextBlock))
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}
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/// 是否为列表块（不限嵌套层级）。
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public static func isListBlock(_ block: STMarkdownRenderBlock) -> Bool {
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if case .list = block { return true }
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return false
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}
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/// 是否为"仅含 strong 节点"的段落（列表相邻时用 listItemSpacing）。
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public static func isStandaloneStrongParagraph(_ block: STMarkdownRenderBlock) -> Bool {
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guard case .paragraph(_, let inlines) = block else { return false }
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return isStandaloneStrongParagraph(inlines: inlines)
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}
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public static func isStandaloneStrongParagraph(inlines: [STMarkdownInlineNode]) -> Bool {
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var sawStrongContent = false
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for inline in inlines {
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switch inline {
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case .strong(let children):
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guard !inlineNodesVisibleText(children).isEmpty else { return false }
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sawStrongContent = true
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case .text(let text), .inlineRawHTML(let text):
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if !text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty { return false }
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case .softBreak:
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continue
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default:
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return false
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}
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}
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return sawStrongContent
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}
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/// 递归提取内联节点的可见纯文本（用于判断节点是否有实际内容）。
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public static func inlineNodesVisibleText(_ nodes: [STMarkdownInlineNode]) -> String {
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var text = ""
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for node in nodes {
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switch node {
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case .text(let value), .code(let value), .inlineMath(let value, _), .inlineRawHTML(let value):
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text.append(value)
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case .emphasis(let children), .strong(let children),
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.strikethrough(let children), .link(_, let children):
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text.append(inlineNodesVisibleText(children))
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case .softBreak:
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text.append("\n")
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case .image(_, let alt, _):
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text.append(alt)
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case .footnoteReference(let label):
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text.append(label)
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}
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}
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return text.trimmingCharacters(in: .whitespacesAndNewlines)
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}
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/// 某块的前一块或后一块是否为列表块（用于判断段落是否紧邻列表）。
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public static func isListAdjacentParagraph(
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previousBlock: STMarkdownRenderBlock?,
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nextBlock: STMarkdownRenderBlock?
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) -> Bool {
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if let prev = previousBlock, isListBlock(prev) { return true }
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if let next = nextBlock, isListBlock(next) { return true }
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return false
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}
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}

‎Sources/STMarkdown/Rendering/STMarkdownCodeBlockMarkerInfo.swift‎

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//
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// STMarkdownCodeBlockMarkerInfo.swift
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// STBaseProject
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//
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import UIKit
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/// 内联代码块头部行携带的元数据，供 overlay 按钮定位使用。
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public final class STMarkdownCodeBlockMarkerInfo: NSObject {
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public let language: String?
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public let code: String
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public let style: STMarkdownStyle
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public let headerHeight: CGFloat
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public let contentInsets: UIEdgeInsets
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public init(language: String?, code: String, style: STMarkdownStyle) {
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self.language = language?.trimmingCharacters(in: .whitespacesAndNewlines)
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self.code = code
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self.style = style
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self.contentInsets = style.codeBlockContentInsets
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let autoHeight = max(
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ceil(UIFont.st_monospacedSystemFont(
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ofSize: max(style.font.pointSize - 2, 12),
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weight: .semibold
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).lineHeight),
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18
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)
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self.headerHeight = style.codeBlockHeaderHeight > 0 ? style.codeBlockHeaderHeight : autoHeight
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super.init()
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}
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}
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public extension NSAttributedString.Key {
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/// 内联代码块头部行标记，值为 `STMarkdownCodeBlockMarkerInfo` 实例。
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static let stCodeBlockMarker = NSAttributedString.Key("com.stbaseproject.stCodeBlockMarker")
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}

‎Sources/STMarkdown/Rendering/STMarkdownInlineCodeBlockRenderer.swift‎

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//
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// STMarkdownInlineCodeBlockRenderer.swift
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// STBaseProject
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//
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import UIKit
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/// 代码块内联文本渲染器。
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///
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/// 将代码块渲染为带背景色的 `NSAttributedString`（非 `NSTextAttachment` 图片），
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/// 适用于两个场景：
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///
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/// - **流式阶段**：每帧逐字追加，避免 O(N²) 全帧图片重绘；
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/// 启用 `tailHighlightOnly` 后仅对末尾 `tailHighlightLines` 行做语法高亮，
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/// 把每帧扫描量压至常数 O(1)。
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///
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/// - **AST 静态阶段**：携带 `.codeBlockMarker` 自定义属性供 overlay 按钮定位，
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/// 避免 TextKit 1 大尺寸图片 glyph rect 计算不准确导致代码块覆盖后续正文。
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///
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/// 两种用途通过 `Mode` 控制，差异仅在头部属性字典和是否截断高亮行数。
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public enum STMarkdownInlineCodeBlockRenderMode {
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/// 流式阶段：跳过业务自定义头部属性，启用尾部高亮截断。
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case streaming(tailHighlightLines: Int)
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/// AST 静态阶段：可附加业务自定义的头部属性（如宿主的 `.codeBlockMarker`）。
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case ast(extraHeaderAttributes: [NSAttributedString.Key: Any])
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}
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public struct STMarkdownInlineCodeBlockRenderer {
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public init() {}
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/// 渲染代码块为带背景色的 `NSAttributedString`。
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///
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/// - Parameters:
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/// - language: 代码语言（nil / 空字符串时显示 "CODE"）
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/// - code: 代码正文
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/// - style: 当前 Markdown 样式配置
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/// - mode: 渲染模式（流式 or AST）
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/// - skipFadeInKey: 流式 shimmer 文字跳过淡入动画的 `NSAttributedString.Key`（传 nil 时不写入）
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public func render(
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language: String?,
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code: String,
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style: STMarkdownStyle,
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mode: STMarkdownInlineCodeBlockRenderMode,
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skipFadeInKey: NSAttributedString.Key? = nil
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) -> NSAttributedString {
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let contentInsets = style.codeBlockContentInsets
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let backgroundColor = style.codeBlockBackgroundColor ?? UIColor.secondarySystemBackground
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let headerColor = style.codeBlockHeaderTextColor ?? style.textColor.withAlphaComponent(0.72)
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let headerFont = UIFont.st_monospacedSystemFont(
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ofSize: max(style.font.pointSize - 2, 12),
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weight: .semibold
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)
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let codeFont = UIFont.st_monospacedSystemFont(
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ofSize: max(style.font.pointSize - 1, 12),
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weight: .regular
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)
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let result = NSMutableAttributedString()
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// 头部段落样式：spacer attachment 撑出左侧间距，确保背景色连续
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let headerParagraphStyle = NSMutableParagraphStyle()
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headerParagraphStyle.tailIndent = -contentInsets.right
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headerParagraphStyle.paragraphSpacingBefore = contentInsets.top
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headerParagraphStyle.lineBreakMode = .byTruncatingTail
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if style.codeBlockHeaderHeight > 0 {
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headerParagraphStyle.minimumLineHeight = style.codeBlockHeaderHeight
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headerParagraphStyle.maximumLineHeight = style.codeBlockHeaderHeight
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}
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let headerText = language.flatMap { $0.isEmpty ? nil : $0.uppercased() } ?? "CODE"
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let headerBaselineOffset: CGFloat = style.codeBlockHeaderHeight > 0
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? (style.codeBlockHeaderHeight - headerFont.lineHeight) / 2
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: 0
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var headerAttrs: [NSAttributedString.Key: Any] = [
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.font: headerFont,
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.foregroundColor: headerColor,
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.backgroundColor: backgroundColor,
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.paragraphStyle: headerParagraphStyle,
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.baselineOffset: headerBaselineOffset,
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]
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if let key = skipFadeInKey { headerAttrs[key] = true }
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// AST 模式写入宿主注入的业务属性（如 .codeBlockMarker）
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if case .ast(let extraAttrs) = mode {
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for (key, value) in extraAttrs {
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headerAttrs[key] = value
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}
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}
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let headerLine = NSMutableAttributedString()
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let spacer = NSTextAttachment()
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spacer.image = UIImage()
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spacer.bounds = CGRect(x: 0, y: 0, width: contentInsets.left, height: 1)
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let spacerStr = NSMutableAttributedString(attachment: spacer)
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spacerStr.addAttributes(headerAttrs, range: NSRange(location: 0, length: spacerStr.length))
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headerLine.append(spacerStr)
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headerLine.append(NSAttributedString(string: headerText + "\n", attributes: headerAttrs))
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result.append(headerLine)
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// 代码体段落样式
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let codeParagraphStyle = NSMutableParagraphStyle()
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codeParagraphStyle.lineBreakMode = .byCharWrapping
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codeParagraphStyle.lineSpacing = max(style.bodyLineSpacing, 2)
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codeParagraphStyle.firstLineHeadIndent = contentInsets.left
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codeParagraphStyle.headIndent = contentInsets.left
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codeParagraphStyle.tailIndent = -contentInsets.right
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codeParagraphStyle.paragraphSpacingBefore = style.codeBlockSeparatorSpacing
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// 语法高亮（流式阶段可截断为尾部 N 行降低 O(N²)）
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let mutableBody: NSMutableAttributedString
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if case .streaming(let tailLines) = mode,
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tailLines > 0 {
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let codeLines = code.split(separator: "\n", omittingEmptySubsequences: false).map(String.init)
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let totalLines = codeLines.count
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if totalLines > tailLines {
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let prefixCode = codeLines.prefix(totalLines - tailLines).joined(separator: "\n") + "\n"
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let suffixCode = codeLines.dropFirst(totalLines - tailLines).joined(separator: "\n")
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mutableBody = NSMutableAttributedString()
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mutableBody.append(NSAttributedString(string: prefixCode, attributes: [
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.font: codeFont,
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.foregroundColor: style.codeBlockTextColor ?? style.textColor,
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.paragraphStyle: codeParagraphStyle,
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]))
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let highlightedSuffix = STMarkdownCodeSyntaxHighlighter.highlightedBody(
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language: language,
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code: suffixCode,
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font: codeFont,
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textColor: style.codeBlockTextColor ?? style.textColor,
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paragraphStyle: codeParagraphStyle
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)
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mutableBody.append(highlightedSuffix)
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} else {
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mutableBody = NSMutableAttributedString(
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attributedString: STMarkdownCodeSyntaxHighlighter.highlightedBody(
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language: language,
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code: code,
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font: codeFont,
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textColor: style.codeBlockTextColor ?? style.textColor,
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paragraphStyle: codeParagraphStyle
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)
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)
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}
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} else {
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mutableBody = NSMutableAttributedString(
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attributedString: STMarkdownCodeSyntaxHighlighter.highlightedBody(
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language: language,
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code: code,
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font: codeFont,
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textColor: style.codeBlockTextColor ?? style.textColor,
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paragraphStyle: codeParagraphStyle
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)
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)
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}
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mutableBody.addAttribute(
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.backgroundColor,
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value: backgroundColor,
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range: NSRange(location: 0, length: mutableBody.length)
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)
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result.append(mutableBody)
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// 尾部：底部间距
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let tailParagraphStyle = NSMutableParagraphStyle()
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tailParagraphStyle.minimumLineHeight = contentInsets.bottom
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tailParagraphStyle.maximumLineHeight = contentInsets.bottom
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var tailAttrs: [NSAttributedString.Key: Any] = [
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.font: codeFont,
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.foregroundColor: UIColor.clear,
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.backgroundColor: backgroundColor,
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.paragraphStyle: tailParagraphStyle,
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]
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if let key = skipFadeInKey, case .streaming = mode { tailAttrs[key] = true }
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result.append(NSAttributedString(string: "\n", attributes: tailAttrs))
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return result
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}
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}

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