| 1 | #if os(macOS) |
| 2 | import AppKit |
| 3 | |
| 4 | extension NSAttributedString.Key { |
| 5 | static let docsTopBlock = NSAttributedString.Key("OficinaDocsTopBlock") |
| 6 | static let docsMarginBefore = NSAttributedString.Key("OficinaDocsMarginBefore") |
| 7 | static let docsMarginAfter = NSAttributedString.Key("OficinaDocsMarginAfter") |
| 8 | } |
| 9 | |
| 10 | /// Mirrors pages.mjs: keep top-level blocks intact and put a visual separator |
| 11 | /// before the next block exceeding the 648pt text budget. All offsets are layout |
| 12 | /// only; an oversized paragraph/list is never split or rewritten to make a page. |
| 13 | @MainActor enum DocumentPageLayout { |
| 14 | struct Result { |
| 15 | var starts: [Int: CGFloat] = [:] |
| 16 | var separators: [CGFloat] = [] |
| 17 | } |
| 18 | /// Mapping IDs, formatting marks and colors do not affect glyph positions. |
| 19 | /// Retain only layout inputs so metadata acknowledgements reuse pagination. |
| 20 | static func measurementContent(_ storage: NSAttributedString) -> NSAttributedString { |
| 21 | let keys: Set<NSAttributedString.Key> = [.font, .paragraphStyle, .kern, .ligature, .baselineOffset, |
| 22 | .attachment, .expansion, .obliqueness, .writingDirection, .verticalGlyphForm, |
| 23 | .superscript, .docsBaseFont, .docsLeading, .docsCodeStart, .docsFirstMargin, |
| 24 | .docsTopBlock, .docsMarginBefore, .docsMarginAfter] |
| 25 | let result = NSMutableAttributedString(string: storage.string) |
| 26 | storage.enumerateAttributes(in: NSRange(location: 0, length: storage.length)) { attributes, range, _ in |
| 27 | result.setAttributes(attributes.filter { keys.contains($0.key) }, range: range) |
| 28 | } |
| 29 | return result |
| 30 | } |
| 31 | static func measure(storage: NSTextStorage, manager: NSLayoutManager, container: NSTextContainer) -> Result { |
| 32 | var result = Result() |
| 33 | var pageTop: CGFloat? |
| 34 | var added: CGFloat = 0 |
| 35 | var previousMargin: CGFloat = 0 |
| 36 | storage.enumerateAttribute(.docsTopBlock, in: NSRange(location: 0, length: storage.length)) { value, range, _ in |
| 37 | guard value != nil else { return } |
| 38 | let glyphs = manager.glyphRange(forCharacterRange: range, actualCharacterRange: nil) |
| 39 | var top = CGFloat.greatestFiniteMagnitude |
| 40 | var bottom: CGFloat = 0 |
| 41 | manager.enumerateLineFragments(forGlyphRange: glyphs) { rect, used, _, _, _ in |
| 42 | top = min(top, rect.minY); bottom = max(bottom, used.maxY) |
| 43 | } |
| 44 | guard bottom > top else { return } |
| 45 | let before = storage.attribute(.docsMarginBefore, at: range.location, effectiveRange: nil) as? CGFloat ?? 0 |
| 46 | let after = storage.attribute(.docsMarginAfter, at: range.location, effectiveRange: nil) as? CGFloat ?? 0 |
| 47 | defer { previousMargin = after } |
| 48 | if let currentTop = pageTop { |
| 49 | if bottom - currentTop > 648 { |
| 50 | // Collapse margins independently on either side of the gap. |
| 51 | let collapsed = max(previousMargin, before) |
| 52 | let separator = top + added - collapsed + max(previousMargin, 12) |
| 53 | let extra = max(previousMargin, 12) + 18 + max(before, 12) - collapsed |
| 54 | added += extra |
| 55 | result.starts[range.location] = top + added |
| 56 | result.separators.append(separator) |
| 57 | pageTop = top |
| 58 | } |
| 59 | } else { pageTop = top } |
| 60 | } |
| 61 | return result |
| 62 | } |
| 63 | } |
| 64 | #endif |
| 65 | |
amadan