fix invisible text by replacing NSRulerView with integrated gutter drawing

src/EditorView.swift

@@ -537,7 +537,6 @@ struct EditorView: View {
         EditorTextView(text: $state.documentText, evalResults: state.evalResults, onEvaluate: {
             state.evaluate()
         })
-        .background(Color(ns: Theme.current.base))
     }
 }
 
@@ -551,20 +550,20 @@ struct EditorTextView: NSViewRepresentable {
     }
 
     func makeNSView(context: Context) -> NSScrollView {
-        let scrollView = NSScrollView()
+        let scrollView = NSTextView.scrollableTextView()
-        scrollView.hasVerticalScroller = true
+        let defaultTV = scrollView.documentView as! NSTextView
-        scrollView.hasHorizontalScroller = false
-        scrollView.autohidesScrollers = true
-        scrollView.borderType = .noBorder
 
-        let textStorage = NSTextStorage()
+        // Build LineNumberTextView reusing the default text container
-        let layoutManager = MarkdownLayoutManager()
+        let tc = defaultTV.textContainer!
-        let textContainer = NSTextContainer(containerSize: NSSize(width: 0, height: CGFloat.greatestFiniteMagnitude))
+        tc.replaceLayoutManager(MarkdownLayoutManager())
-        textContainer.widthTracksTextView = true
+
-        layoutManager.addTextContainer(textContainer)
+        let textView = LineNumberTextView(frame: defaultTV.frame, textContainer: tc)
-        textStorage.addLayoutManager(layoutManager)
+        textView.minSize = defaultTV.minSize
+        textView.maxSize = defaultTV.maxSize
+        textView.isVerticallyResizable = defaultTV.isVerticallyResizable
+        textView.isHorizontallyResizable = defaultTV.isHorizontallyResizable
+        textView.autoresizingMask = defaultTV.autoresizingMask
 
-        let textView = LineNumberTextView(frame: .zero, textContainer: textContainer)
         textView.isEditable = true
         textView.isSelectable = true
         textView.allowsUndo = true
@@ -585,33 +584,16 @@ struct EditorTextView: NSViewRepresentable {
         textView.smartInsertDeleteEnabled = false
         textView.isAutomaticLinkDetectionEnabled = false
 
-        textView.autoresizingMask = [.width]
+        textView.textContainerInset = NSSize(width: 4, height: 8)
-        textView.isVerticallyResizable = true
-        textView.isHorizontallyResizable = false
-        textView.textContainer?.containerSize = NSSize(
-            width: scrollView.contentSize.width,
-            height: CGFloat.greatestFiniteMagnitude
-        )
         textView.textContainer?.widthTracksTextView = true
-        textView.maxSize = NSSize(
-            width: CGFloat.greatestFiniteMagnitude,
-            height: CGFloat.greatestFiniteMagnitude
-        )
-
         textView.registerForDraggedTypes([.fileURL])
 
         scrollView.documentView = textView
 
-        let ruler = LineNumberRulerView(textView: textView)
-        ruler.evalResults = evalResults
-        scrollView.verticalRulerView = ruler
-        scrollView.hasVerticalRuler = true
-        scrollView.rulersVisible = true
-
         textView.string = text
+        textView.evalResults = evalResults
         textView.delegate = context.coordinator
         context.coordinator.textView = textView
-        context.coordinator.rulerView = ruler
 
         if let ts = textView.textStorage {
             ts.beginEditing()
@@ -652,16 +634,13 @@ struct EditorTextView: NSViewRepresentable {
             .foregroundColor: Theme.current.text
         ]
 
-        if let ruler = scrollView.verticalRulerView as? LineNumberRulerView {
+        textView.evalResults = evalResults
-            ruler.evalResults = evalResults
+        textView.needsDisplay = true
-            ruler.needsDisplay = true
-        }
     }
 
     class Coordinator: NSObject, NSTextViewDelegate {
         var parent: EditorTextView
         weak var textView: NSTextView?
-        weak var rulerView: LineNumberRulerView?
         private var isUpdatingImages = false
         private var isUpdatingTables = false
         private var embeddedTableViews: [MarkdownTableView] = []
@@ -684,7 +663,7 @@ struct EditorTextView: NSViewRepresentable {
             ]
             tv.selectedRanges = sel
             updateBlockRanges(for: tv)
-            rulerView?.needsDisplay = true
+            tv.needsDisplay = true
 
             DispatchQueue.main.async { [weak self] in
                 self?.updateInlineImages()
@@ -1042,6 +1021,7 @@ private func highlightMarkdownLine(_ trimmed: String, line: String, lineRange: N
             if contentRange.length > 0 {
                 let h2Font = NSFont.systemFont(ofSize: 18, weight: .bold)
                 textStorage.addAttribute(.font, value: h2Font, range: contentRange)
+                textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
             }
         }
         return true
@@ -1056,6 +1036,7 @@ private func highlightMarkdownLine(_ trimmed: String, line: String, lineRange: N
             if contentRange.length > 0 {
                 let h1Font = NSFont.systemFont(ofSize: 22, weight: .bold)
                 textStorage.addAttribute(.font, value: h1Font, range: contentRange)
+                textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
             }
         }
         return true
@@ -1167,6 +1148,7 @@ private func highlightInlineMarkdown(textStorage: NSTextStorage, lineRange: NSRa
         textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeMarker)
         if contentRange.length > 0 {
             textStorage.addAttribute(.font, value: font, range: contentRange)
+            textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
         }
     }
 }
@@ -1311,6 +1293,7 @@ private func highlightFencedCodeBlocks(textStorage: NSTextStorage, palette: Catp
                 openFence = nil
             } else {
                 textStorage.addAttribute(.font, value: monoFont, range: lineRange)
+                textStorage.addAttribute(.foregroundColor, value: palette.text, range: lineRange)
             }
         }
 
@@ -1344,6 +1327,7 @@ private func highlightInlineCode(textStorage: NSTextStorage, lineRange: NSRange,
         textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: closeTick)
         if contentRange.length > 0 {
             textStorage.addAttribute(.font, value: monoFont, range: contentRange)
+            textStorage.addAttribute(.foregroundColor, value: palette.text, range: contentRange)
             textStorage.addAttribute(.backgroundColor, value: palette.surface0, range: contentRange)
         }
     }
@@ -1398,6 +1382,7 @@ private func highlightTableLine(_ trimmed: String, lineRange: NSRange, textStora
     let boldMono = NSFontManager.shared.convert(monoFont, toHaveTrait: .boldFontMask)
 
     textStorage.addAttribute(.font, value: monoFont, range: lineRange)
+    textStorage.addAttribute(.foregroundColor, value: palette.text, range: lineRange)
 
     if isSeparator {
         textStorage.addAttribute(.foregroundColor, value: palette.overlay0, range: lineRange)
@@ -1708,12 +1693,80 @@ private func resolveLocalImagePath(_ rawPath: String) -> String? {
 // MARK: - LineNumberTextView
 
 class LineNumberTextView: NSTextView {
+    static let gutterWidth: CGFloat = 50
+    var evalResults: [Int: String] = [:]
+
+    override var textContainerOrigin: NSPoint {
+        return NSPoint(x: LineNumberTextView.gutterWidth, y: textContainerInset.height)
+    }
+
     override func drawInsertionPoint(in rect: NSRect, color: NSColor, turnedOn flag: Bool) {
         var widened = rect
         widened.size.width = 2
         super.drawInsertionPoint(in: widened, color: color, turnedOn: flag)
     }
 
+    override func drawBackground(in rect: NSRect) {
+        super.drawBackground(in: rect)
+
+        let origin = textContainerOrigin
+        let gutterRect = NSRect(x: 0, y: rect.origin.y, width: LineNumberTextView.gutterWidth, height: rect.height)
+        Theme.current.mantle.setFill()
+        gutterRect.fill()
+
+        drawLineNumbers(origin: origin)
+    }
+
+    private func drawLineNumbers(origin: NSPoint) {
+        guard let lm = layoutManager, let tc = textContainer else { return }
+        let palette = Theme.current
+        let text = string as NSString
+        guard text.length > 0 else { return }
+
+        var containerVisible = visibleRect
+        containerVisible.origin.x -= origin.x
+        containerVisible.origin.y -= origin.y
+        let visibleGlyphs = lm.glyphRange(forBoundingRect: containerVisible, in: tc)
+        let visibleChars = lm.characterRange(forGlyphRange: visibleGlyphs, actualGlyphRange: nil)
+
+        var lineNumber = 1
+        var idx = 0
+        while idx < visibleChars.location {
+            if text.character(at: idx) == 0x0A { lineNumber += 1 }
+            idx += 1
+        }
+
+        let lineAttrs: [NSAttributedString.Key: Any] = [
+            .font: Theme.gutterFont,
+            .foregroundColor: palette.overlay0
+        ]
+        let resultAttrs: [NSAttributedString.Key: Any] = [
+            .font: Theme.gutterFont,
+            .foregroundColor: palette.teal
+        ]
+
+        var charIndex = visibleChars.location
+        while charIndex < NSMaxRange(visibleChars) {
+            let lineRange = text.lineRange(for: NSRange(location: charIndex, length: 0))
+            let lineGlyphRange = lm.glyphRange(forCharacterRange: lineRange, actualCharacterRange: nil)
+            let lineRect = lm.boundingRect(forGlyphRange: lineGlyphRange, in: tc)
+            let y = lineRect.origin.y + origin.y
+
+            if let result = evalResults[lineNumber - 1] {
+                let resultStr = NSAttributedString(string: "\u{2192} \(result)", attributes: resultAttrs)
+                let size = resultStr.size()
+                resultStr.draw(at: NSPoint(x: LineNumberTextView.gutterWidth - size.width - 4, y: y))
+            } else {
+                let numStr = NSAttributedString(string: "\(lineNumber)", attributes: lineAttrs)
+                let size = numStr.size()
+                numStr.draw(at: NSPoint(x: LineNumberTextView.gutterWidth - size.width - 8, y: y))
+            }
+
+            lineNumber += 1
+            charIndex = NSMaxRange(lineRange)
+        }
+    }
+
     // MARK: - Paste (image from clipboard)
 
     override func paste(_ sender: Any?) {
@@ -1790,95 +1843,3 @@ class LineNumberTextView: NSTextView {
     }
 }
 
-class LineNumberRulerView: NSRulerView {
-    var evalResults: [Int: String] = [:]
-
-    private weak var editorTextView: NSTextView?
-
-    init(textView: NSTextView) {
-        self.editorTextView = textView
-        super.init(scrollView: textView.enclosingScrollView!, orientation: .verticalRuler)
-        self.clientView = textView
-        self.ruleThickness = 50
-
-        NotificationCenter.default.addObserver(
-            self,
-            selector: #selector(textDidChange(_:)),
-            name: NSText.didChangeNotification,
-            object: textView
-        )
-    }
-
-    required init(coder: NSCoder) {
-        fatalError()
-    }
-
-    @objc private func textDidChange(_ notification: Notification) {
-        needsDisplay = true
-    }
-
-    override func drawHashMarksAndLabels(in rect: NSRect) {
-        guard let tv = editorTextView,
-              let layoutManager = tv.layoutManager,
-              let textContainer = tv.textContainer else { return }
-
-        let palette = Theme.current
-
-        palette.mantle.setFill()
-        rect.fill()
-
-        let visibleRect = scrollView!.contentView.bounds
-        let visibleGlyphRange = layoutManager.glyphRange(
-            forBoundingRect: visibleRect, in: textContainer
-        )
-        let visibleCharRange = layoutManager.characterRange(
-            forGlyphRange: visibleGlyphRange, actualGlyphRange: nil
-        )
-
-        let text = tv.string as NSString
-        var lineNumber = 1
-        var index = 0
-        while index < visibleCharRange.location {
-            if text.character(at: index) == 0x0A { lineNumber += 1 }
-            index += 1
-        }
-
-        let attrs: [NSAttributedString.Key: Any] = [
-            .font: Theme.gutterFont,
-            .foregroundColor: palette.overlay0
-        ]
-        let resultAttrs: [NSAttributedString.Key: Any] = [
-            .font: Theme.gutterFont,
-            .foregroundColor: palette.teal
-        ]
-
-        var charIndex = visibleCharRange.location
-        while charIndex < NSMaxRange(visibleCharRange) {
-            let lineRange = text.lineRange(for: NSRange(location: charIndex, length: 0))
-            let glyphRange = layoutManager.glyphRange(forCharacterRange: lineRange, actualCharacterRange: nil)
-            var lineRect = layoutManager.boundingRect(forGlyphRange: glyphRange, in: textContainer)
-            lineRect.origin.y += tv.textContainerInset.height - visibleRect.origin.y
-
-            if let result = evalResults[lineNumber - 1] {
-                let resultStr = NSAttributedString(string: "→ \(result)", attributes: resultAttrs)
-                let resultSize = resultStr.size()
-                let resultPoint = NSPoint(
-                    x: ruleThickness - resultSize.width - 4,
-                    y: lineRect.origin.y
-                )
-                resultStr.draw(at: resultPoint)
-            } else {
-                let numStr = NSAttributedString(string: "\(lineNumber)", attributes: attrs)
-                let size = numStr.size()
-                let point = NSPoint(
-                    x: ruleThickness - size.width - 8,
-                    y: lineRect.origin.y
-                )
-                numStr.draw(at: point)
-            }
-
-            lineNumber += 1
-            charIndex = NSMaxRange(lineRange)
-        }
-    }
-}