Puranjay Savar Mattas
6e1ffb96fd
Convert from git submodule to plain vendored copy. No push access to upstream nodes-app/swift-markdown-engine meant our local fix commit (05c1720) was stranded and unreachable from any remote on fresh clones/CI. Vendoring as plain files folds it into normal repo history instead.
105 lines
4.0 KiB
Swift
105 lines
4.0 KiB
Swift
//
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// LayoutBridge.swift
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// MarkdownEngine
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//
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// Created by Luca Chen on 12.04.26.
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//
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// Thin helper around TextKit 2's NSTextLayoutManager for the handful of
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// character-range queries the editor needs.
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import AppKit
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/// Line height from the bridge, or a font-metric fallback when no bridge is available.
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func layoutBridgeDefaultLineHeight(for font: NSFont, using bridge: LayoutBridge? = nil) -> CGFloat {
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bridge?.defaultLineHeight(for: font)
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?? (font.ascender - font.descender + font.leading)
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}
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final class LayoutBridge {
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private let textLayoutManager: NSTextLayoutManager
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init(_ textLayoutManager: NSTextLayoutManager) {
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self.textLayoutManager = textLayoutManager
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}
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private var textContentStorage: NSTextContentStorage? {
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textLayoutManager.textContentManager as? NSTextContentStorage
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}
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private func textRange(for range: NSRange) -> NSTextRange? {
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guard let tcs = textContentStorage,
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let start = tcs.location(tcs.documentRange.location, offsetBy: range.location),
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let end = tcs.location(start, offsetBy: range.length) else { return nil }
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return NSTextRange(location: start, end: end)
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}
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func defaultLineHeight(for font: NSFont) -> CGFloat {
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font.ascender - font.descender + font.leading
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}
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func boundingRect(forCharacterRange range: NSRange, in textContainer: NSTextContainer) -> CGRect {
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guard let textRange = textRange(for: range) else { return .zero }
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var result = CGRect.null
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textLayoutManager.enumerateTextSegments(
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in: textRange, type: .standard, options: []
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) { _, rect, _, _ in
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result = result.isNull ? rect : result.union(rect)
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return true
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}
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return result.isNull ? .zero : result
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}
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func characterIndex(
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for point: CGPoint,
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in textContainer: NSTextContainer,
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fractionOfDistanceBetweenInsertionPoints fraction: inout CGFloat
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) -> Int {
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guard let tcs = textContentStorage else {
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fraction = 0
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return NSNotFound
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}
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guard let fragment = textLayoutManager.textLayoutFragment(for: point) else {
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fraction = 0
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return NSNotFound
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}
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let fragFrame = fragment.layoutFragmentFrame
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let localPoint = CGPoint(
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x: point.x - fragFrame.origin.x,
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y: point.y - fragFrame.origin.y
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)
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var lineY: CGFloat = 0
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for lineFragment in fragment.textLineFragments {
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let lineBounds = lineFragment.typographicBounds
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if localPoint.y < lineY + lineBounds.height || lineFragment === fragment.textLineFragments.last {
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let lineLocalPoint = CGPoint(x: localPoint.x - lineFragment.glyphOrigin.x,
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y: localPoint.y - lineY)
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let charIndex = lineFragment.characterIndex(for: lineLocalPoint)
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let fragmentStart = tcs.offset(
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from: tcs.documentRange.location,
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to: fragment.rangeInElement.location
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)
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fraction = lineFragment.fractionOfDistanceThroughGlyph(for: lineLocalPoint)
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return fragmentStart + lineFragment.characterRange.location + charIndex
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}
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lineY += lineBounds.height
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}
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fraction = 0
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return NSNotFound
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}
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func invalidateDisplay(forCharacterRange range: NSRange) {
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// In TextKit 2, invalidating layout also triggers redisplay.
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guard textRange(for: range) != nil else { return }
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textLayoutManager.textViewportLayoutController.layoutViewport()
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}
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func removeTemporaryAttribute(_ attrName: NSAttributedString.Key, forCharacterRange range: NSRange) {
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guard let textRange = textRange(for: range) else { return }
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textLayoutManager.removeRenderingAttribute(attrName, for: textRange)
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}
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var firstTextContainer: NSTextContainer? {
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textLayoutManager.textContainer
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}
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}
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