Use visibleRect to compute visible character ranges; add textRange(in:) helper

- Derive visibleCharacterRanges and accessibilityVisibleCharacterRange from
  contentView.visibleRect via NSTextLayoutManager.textRange(in:) instead of
  viewportRange for more accurate results.
- Add NSTextLayoutManager.textRange(in:) to map a rect to a text range.
- Minor cleanup: rename local var to viewportLayoutController and make
  liveResizeLayoutSuppression private.

Author: krzyzanowskim

Sources/STTextViewAppKit/STTextFinderClient.swift

@@ -140,14 +140,15 @@ final class STTextFinderClient: NSObject, NSTextFinderClient {
 
     /// An array of visible character ranges.
     var visibleCharacterRanges: [NSValue] {
-        guard let textLayoutManager = textView?.textLayoutManager,
-              let viewportTextRange = textLayoutManager.textViewportLayoutController.viewportRange,
+        guard let contentViewVisibleRect = textView?.contentView.visibleRect,
+              let textLayoutManager = textView?.textLayoutManager,
+              let visibleTextRange = textLayoutManager.textRange(in: contentViewVisibleRect),
               let textContentManager = textLayoutManager.textContentManager
         else {
             return []
         }
 
-        return [NSRange(viewportTextRange, in: textContentManager).nsValue]
+        return [NSRange(visibleTextRange, in: textContentManager).nsValue]
     }
 
     func rects(forCharacterRange range: NSRange) -> [NSValue]? {

Sources/STTextViewAppKit/STTextView+Accessibility.swift

@@ -113,8 +113,8 @@ extension STTextView {
     // NSAccessibilityStaticText
 
     override open func accessibilityVisibleCharacterRange() -> NSRange {
-        if let viewportRange = textLayoutManager.textViewportLayoutController.viewportRange {
-            return NSRange(viewportRange, in: textContentManager)
+        if let visibleTextRange = textLayoutManager.textRange(in: contentView.visibleRect) {
+            return NSRange(visibleTextRange, in: textContentManager)
         }
 
         return NSRange()

Sources/STTextViewAppKit/STTextView+Scrolling.swift

@@ -12,15 +12,15 @@ extension STTextView {
 
     @discardableResult
     func scrollToVisible(_ textRange: NSTextRange, type: NSTextLayoutManager.SegmentType) -> Bool {
-        let controller = textLayoutManager.textViewportLayoutController
+        let viewportLayoutController = textLayoutManager.textViewportLayoutController
 
         // Ensure layout for the target range before computing its rect
         textLayoutManager.ensureLayout(for: textRange)
 
         // If the range is outside the current viewport, relocate the viewport anchor
         // so that TextKit2 lays out around the target location (O(1) jump)
         let isInViewport: Bool
-        if let viewportRange = controller.viewportRange {
+        if let viewportRange = viewportLayoutController.viewportRange {
             if textRange.isEmpty {
                 isInViewport = viewportRange.contains(textRange.location)
             } else {

Sources/STTextViewAppKit/STTextView.swift

@@ -619,7 +619,7 @@ open class STTextView: NSView, NSTextInput, NSTextContent, STTextViewProtocol {
         }
     }
 
-    var liveResizeLayoutSuppression = false
+    private var liveResizeLayoutSuppression = false
     private var inLayout = false
     private var needsRelayout = false
 

Sources/STTextViewCommon/Extensions/NSTextLayoutManager+Selection.swift

@@ -93,4 +93,13 @@ package extension NSTextLayoutManager {
         }
         return attributedString
     }
+
+    /// Return text range that intesect the rect
+    func textRange(in rect: CGRect) -> NSTextRange? {
+        if let startLocation = self.caretLocation(interactingAt: CGPoint(x: rect.minX, y: rect.minY), options: .allowOutside, inContainerAt: documentRange.location) {
+            let endLocation = self.caretLocation(interactingAt: CGPoint(x: rect.maxX, y: rect.maxY), options: .allowOutside, inContainerAt: documentRange.location)
+            return NSTextRange(location: startLocation, end: endLocation)
+        }
+        return nil
+    }
 }