Fix Some Typesetting Bugs, Add RangeIterator

Author: thecoolwinter

Sources/CodeEditTextView/Extensions/CTTypesetter+SuggestLineBreak.swift

@@ -18,20 +18,20 @@ extension CTTypesetter {
     func suggestLineBreak(
         using string: NSAttributedString,
         strategy: LineBreakStrategy,
-        startingOffset: Int,
+        subrange: NSRange,
         constrainingWidth: CGFloat
     ) -> Int {
         switch strategy {
         case .character:
             return suggestLineBreakForCharacter(
                 string: string,
-                startingOffset: startingOffset,
+                startingOffset: subrange.location,
                 constrainingWidth: constrainingWidth
             )
         case .word:
             return suggestLineBreakForWord(
                 string: string,
-                startingOffset: startingOffset,
+                subrange: subrange,
                 constrainingWidth: constrainingWidth
             )
         }
@@ -72,11 +72,11 @@ extension CTTypesetter {
     /// - Returns: An offset relative to the entire string indicating where to break.
     private func suggestLineBreakForWord(
         string: NSAttributedString,
-        startingOffset: Int,
+        subrange: NSRange,
         constrainingWidth: CGFloat
     ) -> Int {
-        var breakIndex = startingOffset + CTTypesetterSuggestClusterBreak(self, startingOffset, constrainingWidth)
-        let isBreakAtEndOfString = breakIndex >= string.length
+        var breakIndex = subrange.location + CTTypesetterSuggestClusterBreak(self, subrange.location, constrainingWidth)
+        let isBreakAtEndOfString = breakIndex >= subrange.max
 
         let isNextCharacterCarriageReturn = checkIfLineBreakOnCRLF(breakIndex, for: string)
         if isNextCharacterCarriageReturn {
@@ -92,7 +92,7 @@ extension CTTypesetter {
             // Try to walk backwards until we hit a whitespace or punctuation
             var index = breakIndex - 1
 
-            while breakIndex - index < 100 && index > startingOffset {
+            while breakIndex - index < 100 && index > subrange.location {
                 if ensureCharacterCanBreakLine(at: index, for: string) {
                     return index + 1
                 }
@@ -107,9 +107,8 @@ extension CTTypesetter {
     /// - Parameter index: The index to check at.
     /// - Returns: True, if the character is a whitespace or punctuation character.
     private func ensureCharacterCanBreakLine(at index: Int, for string: NSAttributedString) -> Bool {
-        let set = CharacterSet(
-            charactersIn: string.attributedSubstring(from: NSRange(location: index, length: 1)).string
-        )
+        let subrange = (string.string as NSString).rangeOfComposedCharacterSequence(at: index)
+        let set = CharacterSet(charactersIn: (string.string as NSString).substring(with: subrange))
         return set.isSubset(of: .whitespacesAndNewlines) || set.isSubset(of: .punctuationCharacters)
     }
 

Sources/CodeEditTextView/TextLayoutManager/TextAttachments/TextAttachment.swift

@@ -8,7 +8,7 @@
 import AppKit
 
 public struct TextAttachmentBox: Equatable {
-    let range: NSRange
+    var range: NSRange
     let attachment: any TextAttachment
 
     var width: CGFloat {

Sources/CodeEditTextView/TextLayoutManager/TextAttachments/TextAttachmentManager.swift

@@ -95,6 +95,16 @@ public final class TextAttachmentManager {
 
         return results
     }
+
+    package func textUpdated(atOffset: Int, delta: Int) {
+        for (idx, box) in orderedAttachments.enumerated().reversed() {
+            if box.range.contains(atOffset) {
+                orderedAttachments.remove(at: idx)
+            } else if box.range.location > atOffset {
+                orderedAttachments[idx].range.location += delta
+            }
+        }
+    }
 }
 
 private extension TextAttachmentManager {

Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Edits.swift

@@ -46,9 +46,7 @@ extension TextLayoutManager: NSTextStorageDelegate {
         removeLayoutLinesIn(range: insertedStringRange)
         insertNewLines(for: editedRange)
 
-        attachments.get(overlapping: insertedStringRange).forEach { attachment in
-            attachments.remove(atOffset: attachment.range.location)
-        }
+        attachments.textUpdated(atOffset: editedRange.location, delta: delta)
 
         invalidateLayoutForRange(insertedStringRange)
     }

Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Iterator.swift

@@ -14,26 +14,30 @@ public extension TextLayoutManager {
     /// if there is no delegate from `0` to the estimated document height.
     ///
     /// - Returns: An iterator to iterate through all visible lines.
-    func visibleLines() -> Iterator {
+    func visibleLines() -> YPositionIterator {
         let visibleRect = delegate?.visibleRect ?? NSRect(
             x: 0,
             y: 0,
             width: 0,
             height: estimatedHeight()
         )
-        return Iterator(minY: max(visibleRect.minY, 0), maxY: max(visibleRect.maxY, 0), layoutManager: self)
+        return YPositionIterator(minY: max(visibleRect.minY, 0), maxY: max(visibleRect.maxY, 0), layoutManager: self)
     }
 
     /// Iterate over all lines in the y position range.
     /// - Parameters:
     ///   - minY: The minimum y position to begin at.
     ///   - maxY: The maximum y position to iterate to.
     /// - Returns: An iterator that will iterate through all text lines in the y position range.
-    func linesStartingAt(_ minY: CGFloat, until maxY: CGFloat) -> Iterator {
-        Iterator(minY: minY, maxY: maxY, layoutManager: self)
+    func linesStartingAt(_ minY: CGFloat, until maxY: CGFloat) -> YPositionIterator {
+        YPositionIterator(minY: minY, maxY: maxY, layoutManager: self)
     }
 
-    struct Iterator: LazySequenceProtocol, IteratorProtocol {
+    func linesInRange(_ range: NSRange) -> RangeIterator {
+        RangeIterator(range: range, layoutManager: self)
+    }
+
+    struct YPositionIterator: LazySequenceProtocol, IteratorProtocol {
         typealias TextLinePosition = TextLineStorage<TextLine>.TextLinePosition
 
         private weak var layoutManager: TextLayoutManager?
@@ -68,6 +72,39 @@ public extension TextLayoutManager {
         }
     }
 
+    struct RangeIterator: LazySequenceProtocol, IteratorProtocol {
+        typealias TextLinePosition = TextLineStorage<TextLine>.TextLinePosition
+
+        private weak var layoutManager: TextLayoutManager?
+        private let range: NSRange
+        private var currentPosition: (position: TextLinePosition, indexRange: ClosedRange<Int>)?
+
+        init(range: NSRange, layoutManager: TextLayoutManager) {
+            self.range = range
+            self.layoutManager = layoutManager
+        }
+
+        /// Iterates over the "visible" text positions.
+        ///
+        /// See documentation on ``TextLayoutManager/determineVisiblePosition(for:)`` for details.
+        public mutating func next() -> TextLineStorage<TextLine>.TextLinePosition? {
+            if let currentPosition {
+                guard let nextPosition = layoutManager?.lineStorage.getLine(
+                    atIndex: currentPosition.indexRange.upperBound + 1
+                ), nextPosition.range.location < range.max else {
+                    return nil
+                }
+                self.currentPosition = layoutManager?.determineVisiblePosition(for: nextPosition)
+                return self.currentPosition?.position
+            } else if let position = layoutManager?.lineStorage.getLine(atOffset: range.location) {
+                currentPosition = layoutManager?.determineVisiblePosition(for: position)
+                return currentPosition?.position
+            }
+
+            return nil
+        }
+    }
+
     /// Determines the “visible” line position by merging any consecutive lines
     /// that are spanned by text attachments. If an attachment overlaps beyond the
     /// bounds of the original line, this method will extend the returned range to

Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Layout.swift

@@ -77,7 +77,7 @@ extension TextLayoutManager {
         let minY = max(visibleRect.minY - verticalLayoutPadding, 0)
         let maxY = max(visibleRect.maxY + verticalLayoutPadding, 0)
         let originalHeight = lineStorage.height
-        var usedFragmentIDs = Set<UUID>()
+        var usedFragmentIDs = Set<LineFragment.ID>()
         var forceLayout: Bool = needsLayout
         var newVisibleLines: Set<TextLine.ID> = []
         var yContentAdjustment: CGFloat = 0
@@ -162,7 +162,7 @@ extension TextLayoutManager {
         _ position: TextLineStorage<TextLine>.TextLinePosition,
         textStorage: NSTextStorage,
         layoutData: LineLayoutData,
-        laidOutFragmentIDs: inout Set<UUID>
+        laidOutFragmentIDs: inout Set<LineFragment.ID>
     ) -> CGSize {
         let lineDisplayData = TextLine.DisplayData(
             maxWidth: layoutData.maxWidth,

Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager.swift

@@ -71,7 +71,7 @@ public class TextLayoutManager: NSObject {
     weak var textStorage: NSTextStorage?
     var lineStorage: TextLineStorage<TextLine> = TextLineStorage()
     var markedTextManager: MarkedTextManager = MarkedTextManager()
-    let viewReuseQueue: ViewReuseQueue<LineFragmentView, UUID> = ViewReuseQueue()
+    let viewReuseQueue: ViewReuseQueue<LineFragmentView, LineFragment.ID> = ViewReuseQueue()
     package var visibleLineIds: Set<TextLine.ID> = []
     /// Used to force a complete re-layout using `setNeedsLayout`
     package var needsLayout: Bool = false

Sources/CodeEditTextView/TextLine/Typesetter/Typesetter.swift

@@ -48,7 +48,6 @@ final public class Typesetter {
             attachments: attachments
         )
         lineFragments.build(from: lines, estimatedLineHeight: maxHeight)
-
     }
 
     private func makeString(string: NSAttributedString, markedRanges: MarkedRanges?) {
@@ -153,14 +152,16 @@ final public class Typesetter {
         typesetter: CTTypesetter,
         displayData: TextLine.DisplayData
     ) {
+        let substring = string.attributedSubstring(from: range)
+
         // Layout as many fragments as possible in this content run
         while context.currentPosition < range.max {
             // The line break indicates the distance from the range we’re typesetting on that should be broken at.
             // It's relative to the range being typeset, not the line
             let lineBreak = typesetter.suggestLineBreak(
-                using: string,
+                using: substring,
                 strategy: displayData.breakStrategy,
-                startingOffset: context.currentPosition - range.location,
+                subrange: NSRange(start: context.currentPosition - range.location, end: range.length),
                 constrainingWidth: displayData.maxWidth - context.fragmentContext.width
             )
 

Sources/CodeEditTextView/TextSelectionManager/TextSelectionManager+Draw.swift

@@ -13,7 +13,7 @@ extension TextSelectionManager {
     public func drawSelections(in rect: NSRect) {
         guard let context = NSGraphicsContext.current?.cgContext else { return }
         context.saveGState()
-        var highlightedLines: Set<UUID> = []
+        var highlightedLines: Set<TextLine.ID> = []
         // For each selection in the rect
         for textSelection in textSelections {
             if textSelection.range.isEmpty {
@@ -41,7 +41,7 @@ extension TextSelectionManager {
         in rect: NSRect,
         for textSelection: TextSelection,
         context: CGContext,
-        highlightedLines: inout Set<UUID>
+        highlightedLines: inout Set<TextLine.ID>
     ) {
         guard let linePosition = layoutManager?.textLineForOffset(textSelection.range.location),
               !highlightedLines.contains(linePosition.data.id) else {

Sources/CodeEditTextView/TextSelectionManager/TextSelectionManager+FillRects.swift

@@ -37,7 +37,7 @@ extension TextSelectionManager {
             height: rect.height
         ).intersection(rect)
 
-        for linePosition in layoutManager.lineStorage.linesInRange(range) {
+        for linePosition in layoutManager.linesInRange(range) {
             fillRects.append(
                 contentsOf: getFillRects(in: validTextDrawingRect, selectionRange: range, forPosition: linePosition)
             )